1. What we mean by plants	13. Of the increase of grain and seeds
2. Their liquid parts	14. Of male and female plants
3. Their solid parts	15. Of the sleep of plants
4. Of the bark and animals	16. Of the agreement between plants
5. The wood	17. Of the generation of plants
6. The pith	18. Of their flowers
7. The root and branches	19. Their seeds
8. The leaves	20. Their fruits
9. The nutrition of plants	21. Of the perspiration of plants
10. Water not the nutriment of plants	22. Trees inverted will grow
11. The motion of the nutritive juice	23. Of the propagation of several plants
12. The descent and ascent of the sap	24. Of grain planted in various substances

I.BY plants we mean organized bodies, destitute of sense and motion, fixed in the earth, and drawing their nourishment from it by their roots. Touching these, we may consider, first, the structure of their parts, and then their nutrition and gene­ration.

2.The parts of which they are composed are either liquid or solid. The liquid are usually divided into juices and tears. The juice is to the plant, what blood isto an animal, and is various in the various kinds of plants. Tears are liquors which are emitted from them, whether they sweat out of them naturally, or are drawn out of them, either by art, or by the heat of the sun. Some of these remain liquid; others grow, by degrees into a firm consistence.

3. Plants consist of three dissimular, solid parts, the root, the trunk and the branches. In each of these we may observe three similar parts, the bark, the wood, and the pith.

4. To begin with the TRUNK. Here we may first observe the BARK; whose surface consists of little bladders, which surround the trunk like a ring. These, which are commonly filled with some kind of juice, being removed, there occur various ranks of woody fibres, curiously wrought in a kind of network, one row above another. The intervals also between those fibres, are all filled with little vessels. The use of the bark seems to be, not only, like skin, to cover the wood and pith, but also to concoct the: nutritive juice, and forward the growth of the plant. And as to the nutrition of the plant, it is probable the juice ascends from the root, through the fibres, and is sustained by the unevenness therein, till it is lodged in the vessels. In these the new juice being mixed, with that they contained before, is fermented, and rarified to such a degree, as is needful for its nourishment.

It has been a common opinion, that trees only live by the ascent of the sap in the bark, or between the bark and the wood. But this evidently appears to be a vulgar error, from the instance of a large, old elm, in Magdalen College Grove at Oxford, which was quite disbarked all round, at most places two feet, at some four feet from the ground. Notwithstanding this, it grew and flour­ished many years, as well as any tree in the grove. What is more, it was likewise without all pith, being hollow within as a drum. Add to this, that the plane and cork-trees, divest them­selves every year of all their old bark (as snakes do of their skins), and acquire a new one. Now during the change from one to the other, it is clear they are not nourished by the bark. Therefore there must be other vessels, besides those of the bark, capable of conveying the sap. It is probable, the bark may ordinarily do this; but that when the ordinary conveyance fails, some of the woody parts, which were all sap vessels once, resume their ancient office: so far, at least, as to keep the tree alive, though not to increase its bulk. Perhaps this is the use of the sap-vessels in the wood, different from that of those in the bark. These are designed for the continuation of a tree; those in the bark for its augmentation.

It seems the bark in fruit trees is principally designed for the augmentation of the tree itself, while the finer vessels of the woody part, strain and prepare the juices for the fruit. A gen­tleman near Cork, observing that his peachtree grew exceedingly, but bore no fruit, cut off the bark almost quite round, for the breadth of two fingers. The next year the tree hardly grew at all, but bore abundance of fruit.

Again. As animals are furnished with the cellular membrane, which invests and covers all the fleshy parts, and screens them from external cold; so plants are encompassed with a bark, complete with fleshy juices, by means whereof even the winter cold is kept off, and hindered from freezing the juices in the vessels. And those sort of trees, whose bark abounds with oil, remain green all the year round.

5.In the WOOD, likewise, there are observed concave fibres, woven as it were, of various vesicles, and stretching all the length of the wood, as do the fibres of the bark. These have intervals between them, in which are transverse vesicles, reaching to the very pith. There are other fibres, which run obliquely, and are far larger, but not so numerous as the former. In some trees there are also several rows of tubes, which emit a thick milky liquor.

6.The PITR is the middle of the wood. It consists of various rows of hollow globules, covered with a fine membrane. In some trees it contains a peculiar juice, which sometimes hardens, or grows black. In tender shoots the pith (which is frequently hexagonal) is not exactly in the middle; but is nearer the bark on the south side, than on the north side of the plant. It is a constant observation, that the pith lessens as the tree grows. Some have imagined it to be the heart of the plant; but this cannot be. For some trees will flourish and bear fruit after the pith is taken out. Besides this, there is in some trees a BLEA, a white and tender substance, between the bark and the wood.

7.The ROOT has nearly the same vessels as the trunk. Through it the juice passes that nourishes the plant. The roots of some plants are full of hollow threads, which transmit nourishment to the upper parts. This in other plants insinuates itself through the pores that are in the bark of the root. The branches of a plant agree with the trunk, in all the essential parts of its struc­ture.

If no moisture comes to the roots of trees they cannot grow; but if it comes only to the points of the root, though all the rest remain dry, they grow well: for the root shoots out yearly a sharp pointed tender part, somewhat like the Shari) bud on the end of a sprig, by which it not only enlarges itself in breadth, as the branches do above, but also receives its nourishment. And that tender part moves toward the soft and moist earth. So that to loosen the earth at the points of the roots, grealty helps the growth of all plants.

8.On the smallest part of the branches grow the LEAVES: of these we may observe, 1. The fibres of the leaf stand not on the stalk in an even line, but always in an angular or circular posture: and their vascular fibres or threads, are three, five or seven. The reason of this position is, for the more erect growth, and for the greater strength of the leaf: as also for the security of its sap. 2. The accurate position of these fibres, which often take in the eighth part of a circle, as in mallows: in some plants a tenth; but in most a twelfth. 3. The art of folding up the leaves before the eruption, is incomparable both for elegance and security. They take up the least room their form will bear: and are so Conveniently couched, as to be capable of receiving protection from other parts, and of giving it to each other.

Leaves consist of fibres continued from the trunk of the tree. They are clothed with an extremely thin pellicle, ‚which is covered with the finest down. Their skin or coat is only that of the branches extended, as gold is by beating. In the bud they are folded up, almost in the manner of a fan, sometimes in two, sometimes in several plaits. But if they are too thick to plait commodiously in two, and to be ranged against each other, or if they are too small a number, or their fibres too delicate; instead of being plaited, they are rolled up, and form either a single roll, or two rolls, which begin at each extremity of the leaf, and meet in the middle. There are also some plants, as fern in particular, which form three rolls.

The chief use of leaves seem to be, 1. To catch the dew and rain, and so convey more nourishment to the plant, than the root alone could do. 2. To take in air; (of which more hereafter;) and, 3. To minister to a kind of insensible perspiration, by which redundancies may be thrown off.

9. The nutrition of plants seems to be performed thus. As the earth abounds with particles of every sort, those which suit each plant, being dissolved by moisture and agitated by heat, enter the root through its threads or pores, ascend through the woody fibres, and being in the vesicles of the plant mixed with its native juice, and subtilized by fermentation, insinuate them­selves into all parts of it. Part of this nourishes the plant and forms the fruit; the residue transpires. But as all particles are not equally fit to enter the pores of every plant, neither can all be fermented into a juice proper to nourish it: the reason is plain, why every plant will not flourish in every soil.

It is remarkable, that trees of very different kinds, draw their whole sustenance from the moisture they find in the same piece of ground, and from the ambient air and dews. Hence we may infer, that the very contexture of their bodies form the first seed, are the natural limbers, where the common water and air are digested into so many different leaves and fruits.

We see also, that a handful of moss, sometimes above a span long, grows out of a small oyster-shell, without any earth, as do trees out of bare rocks. Hence we easily learn, that the seeds first, and then the roots, stems and leaves of trees, are the strainers which secrete and generate their peculiar saps and juices. These are at first little else than pure air and water, till they are concreted in peculiar salts, by more curious strainers, and inure subtle boilers than art has ever advised.

10. The ancients generally supposed the earth to produce vegetables: many of the moderns ascribe it to water alone. But it is a doubt whether the experiment was made with the nicety that is requisite. And it proves nothing, unless that water be quite pure from any’ terrestrial mixture; for if it be not, the plant may owe its whole growth to that terrestrial matter.

Who can find any water, newly taken out of the spring, which does not exhibit even to the naked eye, great numbers of small terrestrial particles, dispersed through every part of it These are of two general kinds. Some are of a mine ral nature, others of a vegetable. Of the latter some are fit to nourish one plant, or one part of it, and some another. All water is much charged with vegetable matter, which is fine, light and easily moveable. Spring water contains less of it than river water, river water more than rain water.

To which of these waters, or matter sustained therein, do vege­tables owe their growth In order to decide this, the following experiments were made. Several phials of the same shape and size, were filled with equal quantities of water. Over each was tied a piece of parchment, with a hole in it just large enough for the stem, of the plant, to prevent the water from evaporating, or ascending any way but through the plant. Several plants being exactly weighed, were then placed in these phials, and as they imbibed the water, more was added from time to time. Each glass was marked with a different letter, and all set in the same ‘window, from July 20, till October 1. Then they were taken out, the water in each phial weighed, and the plant with the leaves that had fallen off. It then appeared how much each plant had gained, and how much water had been expended upon it.

	Weight of plant put in	Weight whell taken out	Weight gained in 77 days	Expanse of the water	Proportion of the increase to the expense of water.
A. Spear-mint set in springwater	27	42	15	2558	1 to 170
B. Spear-mint set in rain water	28	45	17	3004	1 to 171
C. Spear-mint in Thames’ water	28	54	26	2493	1 to 95
D. Night shade in spring water	49	106	57	3708	1 to 65

The water ascends through the vessels of plants, as through a filtre, And a larger filtre draws more water than a smaller. Therefore, plants that have more or larger vessels, draw more than those that have fewer and smaller.

But the greatest part of the water imbibed by plants, passes through their pores into the atmosphere. Hence the least pro portion of water expended is to the increase of the plant, as 46 or 50 to one. In some it is 100, 200, nay, in one 700 times as much as the increase of the plant.

Nor does this water pass off alone, but bears with it many particles of the plant. The grosser, indeed, are not so easily borne up into the atmosphere, but are usually deposited on the surface of the flowers, leaves or other parts of the plant. Hence our honey-dews, and other gummous exudations. But the finer easily ascend into the atmosphere, and are conveyed to our organs for smell.

Great part of the terrestrial matter mixed with the water, ascends into the plants. After the experiment, there was much more of it in the glasses which had no plants in them, than in those that had. Indeed, this matter being so fine and light, attends water in all its motions: so that filtre it ever so often, some will remain.

The plant increases more or less, as the water it stands in, contains more or less of this matter. So the mint in the glass C. was of much the same bulk and ‚weight with those in A. and B. But standing in river-water, which contained more terrestrial matter than the spring or rain-water wherein they stood, it increased almost double to either of them, yea, and with less expense of water.

But all vegetable matter is not proper for the nourishment of every plant. Although some parts in all may owe their supply to the same common matter, yet others require a peculiar sort of matter, and cannot be formed without it. Yea, different ingre­dients go to the composition of one and the same plant. If therefore, the soil wherein a plant is set, contains all, or most of those ingredients, it will grow there, otherwise not. If there be not as many sorts of particles, as are requisite for the essen­tial parts, it will not grow at all. If they be there, but not enough of them, it will not grow to its natural stature. If the less essential particles be wanting, it will be defective in smell, taste or some other way. But though some land may not contain matter proper for some plants, yet it may for others. All this shews, that plants owe their increase, not to water only, but to a particular terrestrial matter: else there would be no need of manure, or of transplanting them from place to place. The rain falls on all places alike: on this field and that, this garden or orchard and another. Vegetables, therefore, are not formed of water. One plant drew up 2501 grains of this: yet increased only three grains and a half. The mint in B. took thirty-nine grains of water a day, which was much more than the whole weight of the original plant; and yet it gained not one fourth of a grain, in a day and night.

Water, then, is only a vehicle to the terrestrial matter, which forms vegetables. Where this is wanting, the plant does not increase, though ever so much water ascend into it. This is only the agent which conveys that matter to them, and distributes it to their several parts for their nourishment. It is fitted for (his office, by the figure of its parts, which are exactly spherical; therefore easily susceptible of motion, and consequently capable of conveying other matter that is not so voluble. Beside, the constituent particles of water are absolutely solid, and do not yield to the greatest external force: therefore their intervals are always. alike. By this quality water is disposed to receive matter into it: by the former, to tear it along with it.

It is farther qualified to be a vehicle of this matter, by the fineness of its particles. We scarce know a fluid in nature, except fire, whose constituent parts are so exceeding small. They pass pores which air itself cannot pass. This enables them to enter the finest vessels of plants, and to introduce the terres­trial matter to all parts of them; each of which, by means of peculiar organs, assumes the particles suitable to its own nature, letting the rest pass on through the common ducts.

11.As to the motion of the nutritive juice, some think it ascends by the wood, and descends by the bark. But it is not easy to shew, by what particular tubes it either ascends or descends. Neither after all our researches does it appear, what is the principle of this motion Whether there be any such thing as an attractive force in the plant itself; or whether it be performed on the mere principles of mechanism, by the expan­sion of the air contained in the juice, which moves and propels the particles of it into every part of the plant

However, that the sap in plants does circulate is made proba­ble by an easy experiment. On a branch of plain jessamine, whose stem spreads into two or three’ branches, inoculate in autumn, a bud of the yellow striped jessamine. When the tree shoots the next summer, some of the leaves will be striped with yellow, even on the branches not inoculated. And by degrees, the whole tree will be striped, yea, the very wood of the young branches.

It is probable the circulation is performed thus. The wood of plants consists of fine, capillary tubes, which run parallel with each other from the root, and may be looked upon as arteries. On the outside of these, between the wood and the inner bark, are larger tubes, which may do the office of veins. Now the root having imbibed juice from the earth, this is put into motion by the heat. Hereby it is rarefied and caused to ascend in the form of a steam or vapour; till meeting the mouths of the arterial vessels, it passes through them to the top, and to the extreme parts of the tree with a force answerable to the heat whereby it is moved. When it arrives there, meeting with the cold of the external air, it condenses into a liquor, and in that form returns by its own weight, to the root of the venal vessels.

12.That the sap does circulate, appears farther from hence, that the graft will either corrupt or heal the stock. Nay, it changes the very way of the growing of the root, which it could not do, but by sending down its sap thither. Crab-stocks grafted with fruit, which the soil does not like, will canker, not only in the graft, but the stock also. But graft them again with fruit it does like, and it will quickly heal. Farther: graft twenty young pear-stocks with one, sort of pear, and twenty with another. The roots of one sort will grow all alike, and so will those of the other. Yet ever-green grafted on trees which drop their leaves, as the ever-green oak of Virginia upon the common English oak, hold their leaves all the winter. Does not this shew, that the juices circulate in winter, as well as summer, even in the plants which drop their leaves Otherwise those grafted on them must soon die.

It seems that the sap does not rise by the pith: because some large trees are without that part, and yet continue to put forth branches. Indeed no pith is found in those branches of a tree, which exceed two or three years growth. And the pith which is in a branch of this year, is distributed into those boughs which are formed the next season.

Many believe, the tree does not receive its nourishment by the bark; because trees that have lost that part, continue to grow. But they suppose a tree has but one bark; whereas every branch has four distinct coverings. The two outermost of these may be taken from a tree without much damage. But if the two others be taken off, it will infallibly kill the tree.

Some affirm, that the sap neither rises nor falls in the woody part of the tree, because when a branch is cut, they cannot discern any sap issue out of it. Certainly they cannot; because those tubes are not large enough, to receive any thing more gross than vapour. The root receives chiefly in autumn its proper juices, which the warmth in spring raises into a vapour, that gradually ascends through those fine tubes, and by that means causes vegetation.

13. Some have objected to our Lord’s speaking of corn increas­ing a hundred fold, that this is impossible. So far from it, that a grain of barley, has been known to produce two hundred and forty-nine stalks, containing about eighteen thousand grains.

A still more curious experiment was made with turnip seed, at Sutton-coldfield, in Warwickshire. In less than three days after it was sown, the turnips were above ground. In three weeks the roots were as big as walnuts; in less than five weeks, as large as apples. August 12th, one of them weighed two pounds fourteen ounces. At the same time was weighed an ounce of the seed, which had been sown, and it was found to Contain fourteen thous­and six hundred single grains. This being multiplied by forty-six (the ounces that the turnip weighed) produces six hundred and seventy-one thousand six hundred, viz, the number of single grains required to equal the weight of the turnip. Hence it follows, that (supposing the increase was uniform) the grain when it was sown, weighing but of an ounce, increased in the following proportions:

1n six weeks — 671600]

A week — 111933]

A day — 15990}Times its own weight-.

Anhour — — 660]

Aminute— 11]

In June 1766, Mr. Miller sowed some grains of common red wheat. On August 8, a plant was taken up and divided into eighteen parts. Each of these was placed separately. ‘These plants having shot out several side shoots, by the middle of September, they were taken up and divided again. This second division produced sixty-seven plants. These remained through the winter. Another division of them made in the spring, pro­duced 500 plants. They were then divided no farther.

The whole number of ears, which by the process were produced from one grain, was 21109, and from calculation made by count­ing the whole number of grains in one ounce, might be about 576840.

14. Some plants are male and some female. Mr. Miller separated the male-plants of spinach, from the female. The seed swelled as usual, but did not grow when he sowed it. Yet it might have been impregnated another way, as appeared from another experiment. He set twelve tulips about six yards from any other. and as soon as they flowered, carefully took out the stamina. Two days after he saw bees working on other tulips, and coming out loaded with the dust. They flew into the first tulips, and left therein dust enough to impregnate them, which accordingly bore good seed. Thus we see the farina may be carried by insects, and lodged on flowers, which it is fit to impregnate.

Afterwards he bought and sowed some savoy seed, and planted out the plants, but was surprised at the production. For he had some red cabbage, sonic white, some savoys with red ribs, and a mixture of all together in one plant. The gardener assured him, he had carefully saved the seed. Being asked, where he had set the plants for seed, he shewed him, and said, he planted first a dozen white cabbages, next a dozen savoys, and then a dozen red cabbages. Is it not plain that here the effluvia of one sort impreg­nated the other For did each grain of the farina impregnate only its one kind, this mongrel sort could never be produced.

An instance of the same kind has been observed with regard to Indian corn: this is of several colours, as white and red and yellow. If each of these be planted by themselves, they produce their own colour. But if von plant the blue corn in one row, and white or yellow in the next, they will interchange colours: some of the ears in the blue corn-rows, are white or yellow, and some in the white or yellow rows, are blue. That this is caused by the effluvia of one impregnating the other, is manifest from hence:

Place a close, high fence, between the corn of different colours, and there, is no change of colour in any of them.

The HOLLY is described by all naturalists, as bearing herma­phrodite flowers. But by late observations it has appeared, that some trees bear-male, some female flowers. Yet there is a vast variety. In Chelsea garden, some hollies bear female, some her­maphrodite flowers. But some trees bear only male flowers; some only female, some only hermaphrodite. Others bear both male and female, both male and hermaphrodite, or female and hermaphrodite. And others bear male, female and hermaphrodite, all at the same time.

15. That the leaves of certain plants assume at night a disposition different from that of the day, is well known. This has been usually termed, the SLEEP. But to what is this owing Not to the variation of heat or cold, moisture or dryness. For how­ever these are varied, the same timing happens with equal regula­rity. It is LIGHT alone that occasions this change, which by the smallness of its particles, is capable of entering bodies, and by its activity, of producing great changes in them. It changes the position of the leaves of plants, by a motion it excites among the fibres. The natural position of the lobes in these leaves is droop­ing. This is their posture of repose. But vegetation is very imperfectly performed, while they remain in it. It is light which alters that position, by its quick vibrations.

In the evening, August 7, (in order to make a full experiment) Dr. Hill placed a plant of abrus, in a room where it had moderate day-light, without the sun shining upon it. The lobes of the leaves were then fallen perpendicularly from the middle rib, and closed together by their under sides. Thus they continued all night. Half an hour after day break, they began to separate, and a quarter of an hour after sun-rise, were perfectly expanded. Long before sun-set they began to droop again, and towards evening were closed as at first.

Next day the plant was set where there was less light. The lobes were raised in the morning, but not so much. And they drooped earlier at evening.

The third clay it was set in a south window, open to the full sun. Early in the morning the leaves had attained their horizontal situation: by nine o’clock they were raised above it, and con­tinued so till evening. Then fell to the horizontal situation, and thence gradually to the usual state of rest.

The fourth day the plant stood in the same place, but the sun did not appear. The lobes early attained their horizontal situation, but did not rise beyond it, and in the evening closed as usual.

These experiments, prove, that the whole change is occasioned by light only. To put this beyond dispute, in the evening of the sixth day, the plant was set in a book-case, on which the morning sun shone, the doors standing open. 1 he next day was bright. The lobes which had closed in the evening, began to open early in the morning, and by nine o’clock, they were raised in the usual manner. I then shut the doors of the book-case: on opening them an hour after, the lobes were all closed as at midnight. On opening the doors they opened again, and in twenty minutes they were fully expanded. This has since been many times repeated, and always with the same success. We can, therefore, by admitting or excluding the light, make the plant put on all its changes. Hence, we are certain, that what is called the sleep of plants, is caused by the absence of light alone, and that their various inter­mediate states are owing to its different degrees.

It has been supposed that the daily motions of the sensitive plant, were likewise owing to light and darkness; because it expands itself in the morning, and closes again in the evening. From the main branches of this plant spring several smaller ones; and from these others still less, which support the leaves ranged on each side, in pairs over against one another. Several other plants are of the same form, and all these close their leaves in the evening, and open them in the morning, which therefore is not peculiar to the sensitive plant. But this closes them at any time of the day, if touched, and soon after opens them again. You can scarce touch the leaf of a vigorous sensitive plant so lightly, as not to make it close. The large rib which runs along its middle, is as an hinge on which the two halves of the leaf move, when they turn upon being touched, till they stand erect, and by that means meet one another. The slightest touch gives this motion to one leaf; if a little harder, it gives the same, motion to the leaf opposite. If the touch be still rougher, the whole arrangement of leaves on the same rib close in the same manner. If it be stronger still, the rib itself moves upward toward the branch on which it grows. And if the touch be yet more rough, the very branches shrink up toward the main stem. The motion which has the greatest effect of all others upon ‘it, is the shaking one. Winds and heavy rain also cause this plant to close its leaves; but not gentle showers: the contraction being caused by the agitation of the wind, and the strokes given by the large drops.

The natural shutting and opening of its leaves at night and morning, are not so fixed, as not to be variable by many circum­stances. In August, a sensitive plant was carried in a pot into a dark cave; the shaking in the carriage shut up its leaves, so that they did not open for four and twenty hours, and when they did open, they closed no more for three days and nights. Being then brought again into open air, they recovered their natural motions, shutting at night and opening in the morning, as regularly as ever. While in the cave, it was as much affected by the touch as in the open air.

By this and many experiments it appears, that it is not the light that opens these plants, nor the darkness which shuts them. Neither is it owing to the increase of heat or cold. Indeed, great heat will effect them a little, but not in any considerable degree. Concerning the real cause, we may form many conjectures: but nothing certain can be known.

Nearly related to the sleep of plants, is that which Linnæus called the awaking of flowers. The flowers of most plants, after they. are once opened, continue so night and day, until they drop off, or die away. Others, which shut in the night time, open in the morning, sooner or later, according to their situation in the sun or shade, or as they are influenced by the manifest changes of the atmosphere. There are another class of flowers, which make the subject of these observations, that observe a more uniform law in this particular.

These open and shut constantly at certain hours, exclusive of any manifest changes in the atmosphere; and this with so little variation in point of time, as to render the phenomenon worth observation. Linnæus’s observation extends to near fifty species which are subject to this law. We will enumerate some of these, and mention the time when the flowers open and shut. The little blue convolvulus, or bindweed, opens its flowers between five and six in time morning, and shuts them in the after noon. The flowers of the day-lilly open about five in the morning, and shut at seven or eight in the evening. The lesser water-plantain, during its flowering-time, only opens its flowers each day about noon. The flowers of the proliferous pink, expand about eight in the morn­ing, and close again about one in the afternoon. Purple spurrey, expands between nine and ten in the morning, and closes between two and three in the afternoon. This little plant is common among the corn in sandy soils and flowers in June. Common purslain, opens its flowers about nine or ten in the morning, and closes them again in about an hour’s time. The white water-lilly grows in rivers, ponds and ditches, and the flowers lie upon the surface of the water. At their time of expansion, which is about seven in the morning, the stalk is erected, and the flower more elevated above the surface. In this situation it continues till about four in the afternoon, when the flower sinks to the surface of the water, and closes again. Yellow goats-beard, or go-to-bed-at-noon, (the latter of these names was given to this plant long since, on account of this remarkable property) opens its flowers in general about three or four o’clock, and closes again about nine or ten in the morning. These flowers will perform their vigiliæ, if set in phial of water, within doors, for several mornings successively. Sometimes they are quite closed, from their utmost state of expansion, in less than a quarter of an hour.

16. From what has been said it plainly appears, that there is a considerable agreement between plants and animals, as well with regard to their nutrition, as to the structure of their parts. Some extend this farther, arid think there is something in answerable to respiration in animals. They suppose the spiral fibres to be in the place of lungs, and to serve this very Purpose: that in each of these there is a spiral lamina, which is extended or contracted, as it is impelled this way or that, by the elastic air it includes: that these fibres ascending strait through the trunk, are dispersed through all the branches, and thence into the leaves, where they are woven together in a kind of net work.

By this means the more subtle parts of the air are strained through those spiral fibres, to keep the juices of the plant fluid, and perhaps to supply them with nitre or æther, to assist their fermentation.

The air enters vegetables various ways, by the trunk, leaves, roots and branches. For the reception as well as expulsion of it, the pores are very large in some plants. So one sort of walking canes seem full of large pin-holes, resembling the pores of the skin in the ends of our fingers. In the leaves of the pine, if viewed through a glass, they make an elegant show, standing as it were, in rank and file, throughout the length of the leaves.

Air vessels are found in the leaves of all plants, and in many are visible to the naked eye; for on breaking the chief fibres of the leaf, the likeness of a fine woolly substance, or rather of curious small cobwebs, may be seen to hang at both the broken ends. Now these are the fibres of the air vessels, loosed front their spiral position, and drawn out in length.

The pores in the leaves of plants are almost innumerable. Mr. Lewenhock found above a hundred and seventy-two thousand on one side of a leaf or box. The leaves of rue are as full of holes as a honeycomb. Those of St. John’s wort likewise appear full of pin-holes to the naked eye. But the places where those holes seem to be, are really covered with a thin and white membrane. Through a microscope the back aside of the herb mercury, looks as if rough with silver; and all the ribs are full of white, round, transparent balls, fastened by slender stalks, like so many grapes. A sage leaf appears ‘like a rug or shag, full of tufts of silver thrums, and embellished with round crystal beads, fastened by tender foot stalks. The prickles of a nettle are formed for acting just as the sting of animals. Every one of them is hollow, and terminates in a fine point, with an opening near its end. At the bottom of each prickle lies a pellucid bag, containing a clear liquor, which, upon the least touching the prickles, is ejected at the little outlet, and if it enters the skin, causes pain and inflammation by the pungency of its salts.

The leaves of plants are of great consequence to their lifer At these the air passes in, and goes through the whole plant, and out again at the roots. If the leaves have no air, the plant will die, as is easily proved by the air-pump: whereas if the leaves be left on the outside of tire receiver, parted by a hole cemented by wax, while these have air, the plant will thrive and grow, though its roots and-stalks are kept in vacuo. The leaves like­wise chiefly perform the necessary work, (but who can explain the manner !) of altering the water received at the root, into the nature of the juices of the plant. And hence it is, that the life of plants depends so immediately upon their leaves. The hus­bandman often suffers for the want of this knowledge. A crop of saint-foin is valuable; and its roots being perennial, will yield an increase for many years. But it is often destroyed at first, by suffering it to be fed upon by sheep. For if they eat up all the leaves, the root cannot be supplied with air, and so the whole perishes. Leaves being so necessary to all perennial plants, a reversionary stock of them is provided. The leaves of these plants are always formed in autumn, though not unfolded till the following spring. They then open and increase in proportion to the motion of the sap, and the quantity of nourishment the plant receives. These leaves also, though not yet appearing out of the bud, may suffice for’ the extremely small motion, which the sap of those perennial plants, that drop their leaves, has in winter.

But besides these autumnal leaves, there is another set formed in spring and expanding till midsummer. These are of infinite service to many sort of trees, particularly to the mulberry, as they save its life, when the first set of leaves have been all eaten by the silk-worms.

The analogy between the parts of plants and those of animals may now more fully appear. The parts of plants are, 1. The root, composed of absorbent vessels, analogous to the lacteals in. animals: indeed performing the office of all those parts of the abdomen, that minister to nutrition: 2. The wood composed of capillary tubes running parallel from the roots, although the apertures of them are commonly too minute to be seen. Through these, which are analogous to arteries, the sap ascends from the root to the top: 3. Those larger Vessels, which are analogous to veins; through these it descends from the top to the root. 4. The bark, which communicates with the pith by little strings, passing between the arteries. 5. The pith, consisting of trans parent globules, like the bubbles that compose froth.

The sap enters the plant in the form of pure water, and the nearer the root, the more it retains of that nature. The farther it goes, the more it partakes of the nature of the plant. In the trunk and branches it remains acid. In the buds it is more con­cocted. It is farther prepared in the leaves, as blood in the lungs, which being exposed to the alternate action of heat by day, and cold by night, are alternately dilated and Contracted.

Is not then the motion of the sap in plants, like that of the blood in animals, produced chiefly by the action of the air All plants have the two orders of vessels: 1. Those which Convey the nutritious juices. 2. Air vessels, hollow tubes, within which all other vessels are contained. Now the least heat rarifies the air in these air vessels, thereby dilating them, and so causing a per­petual spring, which promotes the circulation of the juices. For, by the expansion of the air Vessels, the sap vessels are pressed, and the ‘sap continually propelled. By the same propulsion it is comminuted more and more, and so fitted to enter finer and finer vessels: while the thicker part is deposited in the lateral cells of the bark, to defend the plant from cold and other injuries.

Thus is every plant acted on by heat in the day time, especially in summer; the sap protruded, then evacuated, and then exhaust­ed. In the night the air vessels being contracted by the cold, the sap vessels are relaxed, and disposed to receive fresh food. for the next day’s digestion. And thus plants do, as it were, eat and drink, during the night season.

The vessels themselves consist of mere earth, cemented by oil and water: which being exhausted by fire, air or age, the plant returns to its earth. Thus in plants, burnt by the ‘fiercest fire, the matter of the vessels is left entire: which consequently is neither water, air, salt, nor sulphur, but earth alone. The sap consists of some saline parts: others derived from air, rain and putrified plants or animals. Consequently in plants are contained, salts, oils, water, earth: and probably all metals too. In fact, the ‘ashes of all vegetables yield something which the loadstone attracts.

There is a considerable difference as to the time when different plants revive after the winter. No sooner does tire sun begin to warm the earth, than time vernal flowers appear, and the trees, one after another, open their buds, and clothe themselves with leaves. But why do many wood plants, as colts-foot, pile-wort, violets; and many garden plants, as snow-drops, assara-bacca, crocus, flower in the very beginning of spring, when we cannot by any pains or care, bring them to flower after the summer solstice Nay, these very plants, which are so patient of cold in spring, are in the autumn so very weak and tender, that they die on the first touch of frost, Why, on the ‘contrary, do thistles and many other plants, never flower’ before the summer solstice

In the same manner, trees observe fixed laws, and a certain order in their leafing. Does the cause lie in the different depth of their roots If so, shrubs would have leaves before trees of the same kind. But they have not. We can only say, the fact we know; but the reason of it we know not.

The order of the leafing of several trees and shrubs, observed in Norfolk, in 1755, was as follows:

1. Honey suckle, - - January15.

2. Goosberry,currant, elder, - - March 11.

3. Birch, weeping-willow, - April1.

4. Rasberry,bramble, - 3.

5. Briar, -

6. Plumb, apricot, peach, - 6.

7. Filbert, sallow, alder, - - - 7.

8. Sycamore, - - - - -

9. Elm, quince, - - - - - 10.

10. Marsh-elder, - - - - 11.

11. Wych-elm, - - - 12.

12. Horn-beam, - - - 13.

13. Apple-tree, - - - 14.

14. Abel, chesnut, - - - - 16.

15. Willow, - - - - -‚ 17.

16. Oak, lime, - - - - 18.

17. Maple, - - - - - - 19.

18. Walnut, plane, black poplar, beech, - 21.

19. Ash, Carolina poplar, - - - 22.

Indeed the leafing of several of these varies much, as the spring ‘is earlier or later. But others of them, be the winter ever so mild, do not put out before their time. This also depends on some secret properties, which man is not able to explain.

17. As to the GENERATION of plants, first the tree produces buds, which afterwards expand into leaves, flowers or branches. In the buds, entire plants are contained. A small stalk, consisting of woody and spiral fibres, springs out of the middle of the plant, wherein the bud inheres. It is involved in a thin bark, which may be divided into various leaves, lying one upon another like scales.

18. Buds are followed by leaves and flowers. In FLOWERS we may consider, 1. The calix or outer cup, designed to be a security to the other parts of the flower. Those whose leaves are firm and strong, as tulips, have no calix at all. Carnations, whose leaves are strong but slender, have a calix of one piece. Others have it consisting of several pieces, and in divers rounds. 2. The foliation or petala, the flower-leaves, which are properly the flower itself. In these, not only the admirable beauty and luxuriant colours are observable; but also their curious folding in the calix, before they are expanded.

It is remarkable, that many, if not most vegetables, especially those of a tender kind, expand their flowers, or down, every day, if it be warm, sun-shiny weather. But they close them as the evening approaches: and some, at the approach of rain. This is particularly done at the beginning of flowering, while the seed is young and tender: as is easily seen in the down of dandelion, and eminently in the flower of pimpernel. These serve as a weather glass to the countryman: by the opening or shutting of these, he can tell without any danger of being deceived whether the weather will be foul the next day.

The flower is as it were the womb, which contains the eggs or seeds of plants, and in due time brings them forth. It is near the bud, and lies hid with it during the winter, till it is brought out by the heat of the summer. The most simple plants bear a bud, which contains a seed of an oval figure. We may easily distin­guish from the flower itself, the leaves of the covering which. involves the bud. From these arise the leaves of the flower, serving for the last concoction of the sap; in which are both woody and spiral fibres, with various rows of utricles. In the middle of flowers, filaments and little pillars arise, whose extre­mities’ are covered with a kind of dust. These pillars are hollow, and have vesicles full of liquor, and the rudiments of seeds, which gradually grow and harden.

That dust is of two kinds, male and female. The male dust is formed in the top of the filaments, where, when it is ripe, it bursts its case, and is split on the heads of the pillars, and thence conveyed to the utricle or matrix thereof, to impregnate the female dust contained therein.

Thus dust in any one plant being viewed with a microscope, every particle is of the same size and figure. But in different plants, the colour, size, and figure are widely different. In some it is clear and transparent as crystal; in others white and opake: in some blue, purple or red, and in others, flesh-coloured. And its colour varies in the same species, suppose tulips, accord­ing to the colour of the flower.

The most general figure is the oval, more or less sharp at the ends, with one or more furrows running lengthways. But the seeds of melilot are cylinders. Those of the pansy are prisms, with four irregular sides. Others represent two crystal globules fastened together. Those of the jonquille are in the form of a kidney. But indeed varieties are not possible to be numbered. The office of the blossom is partly to protect, partly to draw nourishment to the embryo, fruit or seed. The gourd, pumpkin, melon, cucumber, and most bearing trees, have both male and female blossoms on the same plant. Male-blossoms, (usually called cat-skins) may be distinguished from female, by having no pistil or rudiment of fruit about, them; but only a large thrum, covered with dust in their middle. The female blossoms have always a pistil within the flower leaves; and the rudiments of the fruit are always apparent, at the bottom of the flower before it opens.

But there is a species of willow, which appears to change its sex every year. One year it produces male blossoms, and female blossoms the next.

19. The when it is ripe, is enclosed in a peculiar covering In some plants it so increases, as to become a fruit. And in these also we find fibres and utricles dispersed with endless’ variety.

Various are the methods which the wisdom of God takes for sowing seeds of various kinds. Those of arum and poppy are heavy enough to fall directly to the ground. Others that are light, have hooks to stop them from straying too far from their proper place. So have agrimony and goose-grass, the one wanting a warm bank, the other a hedge for its support.

On the other hand many seeds have wings, that the wind may carry them off the plant, and may scatter them asunder; that they may not fall together, and come up too thick. The kernels of pines have very short Wings, just enabling them to flutter on the ground. But some seeds have many long feathers, by which they are wafted about every where.

Others are lodged in elastic cases, which dart out the seed to the convenient distances. Thus wood-sorrel, having a running root, needs to have its seed sown distant from each other. And this is done, by means of a tendinous cover, which when it begins to dry, bursts open on one side in an instant, and is violently turned inside out. The seed of imarts-tongue ‘is dispersed in a different manner. It has a spring wound round its case; when it is ripe, this suddenly breaks the case in two halves, and so throws out the seed. Equally remarkable is the way wherein fern-seed is scat­tered. If a quantity of this be laid on a paper, the seminal vesicles burst, and are seen by a microscope projecting the seeds to a considerable distance.

The seeds of the several species of fern, were wholly unknown to the ancients. But it is now well known, that in the female fern, the whole surface of the leaf on the under-side is covered with a congeries of seeds, so that they guard one another, and need no other covering. And in the common male fern, there are found at the proper seasons several brown spots placed in a very regular manner. These are a fungous matter, round which the small seed vessels are inserted.

The fruitfulness of plants, in producing seeds, transcends all imagination. An elm living a hundred years, ordinarily pro­duces thirty-three millions of seeds. Add, that if its head be cut off, it puts forth as many branches within half an inch of the place where it was cut as it had before. And at whatever height it is cut off, the effect will be the same. Hence it appears, that the whole trunk, from the ground to the rise of the branches, is full of embryo-branches, each of which will actually spring forth, if the head be lopped off just over it. Now if these had sprung out they would have borne an equal number of seeds with those that did. These seeds therefore are already contained in them: and if so, the tree really contains 15840000000 seeds, wherewith to multiply itself as many times. But what shall we say, if each seed contains another tree, containing the same number of seed and if we can never come, either at a seed which does not contain trees, or a tree which does not contain seed

Timber trees of any kind, might certainly be planted to more advantage than they generally are There is a forest two miles from St. toe, in Normandy, planted chiefly with oaks, many of which are but of a moderate height, though of a large circumference. But near its entrance from St. Loc, there is a plantation, about twenty-five years old, wherein none of the oaks are under seventy, and some a hundred feet high. They are set so close, that they almost seem to touch one another, and are no more than four or five inches in diameter. This timber is of great use, both for making charcoal, and many other purposes. And the owners may reap four crops of them in a hundred years.

This forest belongs to the king of France, who ordered the ‘plantation to be made by way of trial. And his ministers have caused several of these trees, a hundred feet high, to be trans­planted, to leave standing proofs of the wonderful effects o the experiment.

As to sowing, the perfection of agriculture consists in setting plants at due distances, and giving a sufficient depth to the roots, that they may spread and receive due nourishment. Yet this is little regarded; but all sorts of grain are sown by handfuls east at random. By this means four parts in five of the seed is utterly lost. To remedy this, a Spanish gentleman contrived an engine (described in the philosophical transactions, under the name of the Spanish sembrador) which being fastened to the plough, the whole business of ploughing, sowing and harrowing, is performed at once; and the grain is spread at equal distances and equally deep in the furrow. An experiment being made, land which usually produced five fold, by this means produced sixty fold. One stalk is all that springs immediately from one grain: but on the sides of this, near, if not within the ground, issue several lateral stalks. And some of these send forth roots, whence one or several other stalks spring, if they are early formed, the soil good, and the weather favourable. By this means one grain of wheat planted in a garden has produced ninety, yea, a hundred ears. If then each ear, taking one with another, contains fifty grains, a single grain may produce five thousand. Nay, a gentleman in Yorkshire, who made the experiment in his garden, some years ago, counted upwards of eight thousand grains which sprung from a single one.

After all that has been’ said and wrote for so many centuries, on the generation or propagation of plants and animals, a late author, to whom the French naturalists in general subscribe, totally denies the whole, and censures all who pretend to discover any animalcula in the semen of animals. He will by no means allow, that every animal or plant, proceeds from an egg lodged in the parent plant or animal. On the contrary, he supposes, “there are in matter certain organical parts, disposed for the formation of animal and vegetable substances, which by coalition constitute the first stamina of all animal and vegetable bodies. These are simple, uniform, common to all, and consequently to be found more or less in every portion of the nutritive juice. From thence they are digested, and when the subject becomes adult, secreted for the formation of the seed of every plant and animal. These organical parts, moving when disengaged, and thence imagined to be alive, are extremely simple in their compo­sition, being perhaps, only elastic springs, more or less com­pressed, more or less diversified in the direction of their force.

All microscopic animals, so called, are indeed no other than such organical particles. Seeds maccrated in water, first disunite into small particles, which soon after move and seem alive, though they are not so. The same may be observed of the juices of animals, as mutton gravy and the like. And as to the common imagination, that the male semen, while in the vessels, contains millions of animalcula like tadpoles, it is certain, they are pro­duced, after the evacuation of the fluid, and rise from principles contained therein, by a real vegetation, and a subsequent change from the vegetable to the animal life.

“ Semen immediately evacuated is an homogenuous fluid. In a few minutes it begins to separate, and after this a kind of vegeta­ble filaments grow in it, and shoot out ramifications on every side. These open and divide into moving globules, which trail after them, something like long tails; which are in truth only strings of the viscid matter, from among which the globules were sepa­rated. By degrees the globuics get rid of them, and then move at case.

“This vegetable power of shooting into filaments, is in all animal and vegetable substances, down to the least microscopic point. And to this is really owing, all that is called animal life, in the fluids produced from vegetables.

“In all our observations on these substances, the whole quan­tity of matter, after a separation of some volatile and saline parts, always divides into filaments, and vegetates into numberless zoo­phytes, which afterwards yield all the species of microscopic animals. After this, those supposed animals themselves subside to the bottom of the liquor, become motionless, resolve into a gelatinous fliamentous substance, and then afford new zoophytes, or animals of.a smaller kind.

“Hence we may observe, that every animal or vegetable sub­stance, advances as fast as it can, to resolve into one common principle, which is the source of all: a kind of universal semen, from which each atom may again ascend to a new life. These animalcula then in the semen of animals, and in the infusions and juices of animal and vegetable substances, are not of the nature of any other beings, nor to be ranked with them. They constitute a class apart from all others, the characteristic of which is, that they neither are generated, nor subsist by nutriment, like other plants or animals, nor do they generate in the ordinary way.”

What then becomes of this whole boasted branch of modern philosophy If this be so, most of our micfoscopic discoveries vanish: into air.

Blue flowered gentianella requires wet weather to be sown in. As socn as any rain touches the seed-vessels, they burst open and throw the seed on each side. Cardamines burst their pods and dart out their seed on a light touch of the hand: nay, the carda­mine impatiens does so, even by the approach of the hand. Other seeds by their agreeable taste or smell, invite birds to feed upon them, who drop them again, fertilized by passing through their body. So mistletoe is usually sown.

The berries of mistletoe have within their viscid pulp, a kernel covered with a thin, whitish skin. One placed these berries within the bark of oak, ash, beech, pear, and apple trees, by making several cuts in the sides of the trees, but the whole berries would not stay in any of them. And when he broke them, the seed always slipt out ofthe edge of the cut, and there stuck to the bark by its viscous covering. He stuck one seed to the bark without cutting at all, which succeeded best, and yielded two plants. The viscous matter drying away, drew the seeds close to the bark, and on these, with two more on an appletree and one on a pear-tree, there began in spring to shoot out at the end of the seed next the eye of the berry, a small deepgrecn shoot, like a little clasper of a vine. At first it rose upwards, then turning again, swelled out somewhat bigger round the end: yet leaving the tip quite flat, forming as it were a foot to stand upon. This foot in June came to the bark, and fixed itself thereon. Being thus fastened at both ends, it formed a little arch, whose diameter was as long as the seed. Thus it remained till March following. Then the other end let go its hold, and raising itself upward, became the head of the plant, while the end which sprung out first, became the root, It is not uncommon for the seeds of ever­greens to be two years before they spring out of the ground. But this was surprising, the change of the ends, first one shooting out, and then the other. Yet we find nature is uniform, and even in this strange plant, acts as in other vegetables, first carrying the sap to form the root, then turning the course of it back again, to send out the upper part of the plant. The strange St circumstance is, that the rooting end should first shoot into the air, and then turn down to find a place to fix on. This it is, which has kept the world so long in ignorance about the growing of this seed. For by requiring a new, smooth part of the bark whereon to fix the rooting part, it has frustrated all attempts of sowing it as we do other seeds.

In strawberries and rasberries the hairs which grow on the ripe fruit, are so many tubes leading to the several seeds. And therefore we may observe, that in the first opening of the flower, the whole inward area is like a little wood of these hairs: and when they have received and conveyed their globules, the seeds swell and rise in a fleshy pulp.

The manner wherein mosses in general seed, is exceedingly little understood. But in one species at least, it may be clearly explained, from a number of observations. The head of this moss appears to the naked eye, smooth and of a pale, brown colour. The top of this is bounded by an orange coloured ring, which is a calix, containing sixteen pyrandal stamina, loaded with a white farina These bend toward each other, and when the head is nearly ripe, almost meet in a point at their tops. Immediately under the arch formed by these stamina, is placed a slender, hollow pistil, through which the farina makes its way, and is dispersed among the seeds in the head. The external membrane of the head, is a continuation of the outward covering of the stalk. A section of the head shews, that this membrane includes a seed vessel so large as to fill it every way. This is filled with perfect and beau­tiful seeds. They are round and transparent when unripe, but afterwards they are opake, and of a beautiful green. The number of seeds in one of these heads, is not less than 13,800.

The seed vessels of mahogany trees are of a curious form. They consist of a large cone, which splitting into five parts, dis­close their winged seeds. None would think, that so tall and so large trees could grow on solid rocks. They are four feet and upwards in diameter. The manner of their growth is as follows. The seeds fly along the surface of the ground, and some falling into the chinks of the rocks, strike root, then creep out upon the surface, and seek another chink. In this they swell to such a size and strength, that the rock splits and makes way for the root to sink deeper. And with this little nourishment the tree in a few years grows to that stupendous size.

The progress of germination was accurately observed by Mal pighi, in the seed of a gourd. The day after it was committed to the ground, he found the outer coat a little swelled: and in its tip a small cleft appeared, through which the sperm was seen. The second day the outward coat was much softer, the inner torn and corrupted, the germ somewhat longer and more swelled, and the beginning of the root appeared. The third day the root had made itself a passage through the coat, near the former cleft. The germe and seethleaves also were now grown much bigger. On the sixth more of the seed-leaves had broken through, and were found thicker and harder. The root had shot out many fibres, and the stem grown a finger’s length. About the twenty first day the plant seemed complete, from Which time the seed­leaves began to droop, till they died away.

20. The parts of different FRUITS are different: but in all the essential parts of the fruit, are only continuations of the fibres, observed in the other parts of the tree. And there is a direct communication between the fruit and the remotest part of the tree. Thus an apple cut cross-ways appears to consist of four parts. 1. The skin, derived from the outer bark of the tree. 2. The pulp, which is an expansion of the inner bark. 3. Ramifi­cations of the woody part of the tree, dispersed throughout the pulp. To these are fastened the coats of the kernels; and these being at first extended to the flower, part of them directly and part obliquely, furnish it with its nourishment. But the fruit increasing intercepts the aliment; and then the flower is starved and falls off.’ 4. The core which is a production of the pith of the plant, strengthened by fibres of the wood intermixed. This is ‘a case for the kernels, filtrates the juice of the pulp, and conveys it to them.

Fruit serve not only for the food of animals, but to guard and nourish the seed enclosed; to filtrate the coarser part of the nutritious juice, and transmit only the purest for the support and growth of the plantule.

In every sort of grain, wheat, barley or any other, there are three particulars observable: 1. The outer coat, which contains all the rest. This in the same species’ of grain, is of a very different thickness in different years, as also in different soils.

2.The germe or bud. This is always hid in the grain, and is the plant in miniature. And, 3. The meal, which is enclosed in the skin that surrounds the germe, and gives it nourishment, when first put into the earth, before it is capable of drawing it from the earth itself.

The whole structure of the plant which produces these grains is equally admirable. The chaffy husk is well adapted to defend the grain, as long as that is necessary, and then to let it fall. The stalk, hollow and round, is at once light and strong, capable of sustaining the ear, without absorbing too much of the juices destined for its nourishment. And the beards are a defence against the birds, that would otherwise destroy the grain before it ripened. The covering of the grain is formed of fibres, which meet in a line and form a kind of furrow. This is the place at which the seed, when moistened, is to burst open. Were not these means prepared for the germe’s coming out, the toughness of the outer coat, would have kept in both the meal and the germe, till they had rotted together.

Nor is this the only use of this place of opening. The grain is designed not only for feed, but for food also. Men have art enough to erect machines for reducing it. to powder. But the birds eat it as it is, and it would pass them whole without doing them any good, were it not, that when it is moistened, it bursts open at the furrow and yields them nourishment

The meal is composed of an infinite number of round, white, transparent bodies. These enclose the young plant, and by their figure, being easily put in motion, as soon as affected by the heat and moisture of the earth, they insinuate into the vessels of the plant, and give it increase, till it is in a condition to feed on the Juices of the earth. The same process of nature is observable, when grains of corn grow out of time, on being thrown carelessly together, in a moist place.

21. Plants do likewise perspire. To find the quantity imbibed and perspired by plants, Dr. Hale took a pot with a large sun­flower planted in it, and, by various experiments, found the greatest perspiration, in a very warm day, to be one pound fourteen ounces; the middle perspiration one pound four ounces. It perspired three ounces in a warm night, when there was no dew. If small dew fell, it perspired nothing; if a large dew it gained two or three ounces.

The weight of the flower was three pounds: the weight of a well sized man is one hundred and sixty. The flower perspires twenty-two ounces in twenty-four hours: the man about twenty­five: beside six ounces, which are carried off by respiration from the lungs.

A middling man eats and drinks in twenty-four hours, about four pounds ten ounces. The plant imbibed and perspired in the same time twenty-two ounces. But taking bulk for bulk, the plant imbibes seventeen times more food than the man. For, deducting five ounces for fæces, there will remain but four pounds five ounces, which enter the veins, and pass off in twenty-four hours. And since taken bulk for bulk, the plant imbibes so much more food than the man, it was necessary by giving it an extensive surface, to provide for a plentiful perspiration, since it has no other way of discharging superfluities as a man has. It was necessary likewise, that the plant should imbibe a larger quantity of fresh fluid than the man, because the fluid filtrated through its roots does not contain so many nutritive particles, as the chyle which enters ,our veins.

But there is a latitude of perspiration both in men and plants. In this flower it varied from sixteen to eighteen ounces during twelve hours day, as it was watered less or more: in a healthy man it varies from a pound and a half to three pounds.

Evergreens perspire far less than other plants. In proportion, they need less nourishment: hereby they are better able to bear the winter: like insects, which as they perspire little, live the whole winter without food.

In order to try whether any sap rose in winter, he made various experiments: from all which it appeared, it does rise then also, but in small quantities. And hence we see why an evergreen grafted on an oak, will remain verdant, when the oak leaves drop. Perspiring less, it needs less nourishment than the oak, and so is sufficiently fed by the sap that rises even in winter.

In summer, when hot sunshine follows a shower, the vines in the middle of a hop-ground are often scorched up, almost from one end of a large ground to the other: at the same time the vapours ascend plentifully. The scorching of the vines seems to be caused by these scorching vapours, which ascend most in the middle of the ground, the air there being more dense, and consequently hotter than on the outsides.

The white clouds likewise which appear in summer time, occasion a vehement heat, by reflecting many of the solar rays, which otherwise would not touch the earth. And if the sun be on one side, and the clouds on the other, they are perfect burning-glasses.

Sometimes there is a kind of hollow clouds, full of hail or. snow. During the continuance of these, the heat is extreme, since by such condensation they reflect more strongly. By these likewise, those blasts may be produced, as well as by the reflec­tion of dense vapours.

The sunflower being tender, if the sun rises clear, faces to the east. The sun continuing to shine, at noon it faces to the south, and at six in the evening to the west. The cause is, that side of the stem which is next the sun, perspires the most, and thereby shrinks.

What degree of heat will plants bear The common tempe­rate point in the thermometer is , eighteen degrees. The external heat of a human body, will raise it to fifty-four degrees. Very hot sunshine will raise it to eighty-eight. Plants endure a consider­ably greater heat than this, near the line, for some hours a day. But the hanging of the leaves of many of them shews, they could not long subsist under it.

The winter heat is from the freezing point to ten degrees; the vernal and autumnal, from ten to twenty. The May and June heat is from seventeen to thirty, in which the generality of plants flourish best. The heat of July is, in the shade, about thirty-eight degrees; in the sunshine, at noon, about fifty. The heat of a hotbed, when too hot for’ plants, is eighty-five or more: and near this is the heat of the blood in high fevers. The due heat of a hotbed is fifty-six degrees; and the same heat hatches eggs.

A continual steam is ascending during the summer; the sun­beamsgiving the moisture of the earth, at two feet depth, a brisk, undulating motion, which rarified by heat, ascends in the form of vapours And the vigour of warm and confined vapour, such as that is which is two or three feet deep in the earth, must be great, and penetrate the roots with some vigour; as we may reasonably suppose, from the vast force of confined vapour in the engine for raising water by fire.

Though vegetables have not, like animals, an engine which, by its alternate dilatations and contractions, drives their juices through them, yet has nature contrived other means, powerfully to raise the’ sap and keep it in motion. And their. root- are covered with a very fine thick strainer, that nothing may enter but what can be readily carried off by perspiration.

That there is a lateral communication of the sap-vessels in plants, as of the blood-vessels in animals, plainly appears from. the experiment of ina.rching trees. For when three wall-trees are thus incorporated, the root of the middlemost may be dug up, and the tree will grow, still, as receiving nourishment from the trees with which it is Connected.. And hence elders, willows, vines and most shrubs, will grow ‘with their tops downward in the earth. For the same reason, if you frequently, in an evening, ‘wash the bodies of new planted trees, they will grow quicker and better than any others of the same plantation.

22. If the top of a VIBURNUM is planted in the ground, it becomes roots, and the roots turned up become branches; and the plant grows exactly as well as it did in its natural position, whether the vessels which fed the branches have changed their course, or whether the juices go up and down the same vessels.

23. I cannot better conclude this chapter, than by ti-acing the analogy between the propagation of animals and that of vege­tables. The roes of fishes, the eggs of insects, birds, and all other animals nearly resemble each other. They are compact bodies of such forms as best suit their natures. They all have integuments, nobly contrived for their preservation, with firm coverings to secure them from outward injuries. Those to be kept in the body have coverings also; but soft and membranous. Every kind contains its peculiar substance, differing from that of every other kind. And all these characters belong also to seeds of every kind. They have their coverings, more or less compact, according to their’ necessities. Their forms are convenient. The substances they contain are specifically different from each other: and their offspring proceeds from them in the same manner, as animals proceed from their eggs.

But beside the substances peculiar to each seed, there is a peculiar organization treasured up in each, which is the rudi­ment of the future plant, capable of being propagated into such a plant as it sprung from, and no other. So in every one of the nut-kind, there is a visible organization, peculiar to each species. And if such an organization appear in every seed, which is large enough to be viewed clearly, we cannot reasonably doubt of their existence, even in those which are so small as to escape our sight. There are multitudes of seeds, which produce large plants, and yet appear only like dust, and a vast number, which we cannot see, but by the microscope. And yet these doubtless have all their peculiar forms, and their organizations as well as the larger.

But from what are these organizations produced Row does’ every plant or animal bring forth a fresh one after its kind A little of this we may understand, if we trace a tree and arm animal through every stage from the egg to their utmost growth.

See a young tree pushing out its leaves and flowers, till it has extruded an entire set of boughs and branches. One part regularly opens after another from the first shoot till it comes to per­fection. Then, and not before, it produces seeds, containing the rudiments of the trees ‘like itself. The fibres of its general organization grow into little knots, some to form leaves, some the calix; some the petals, some the pistil and utricle, some again the little seeds, each growing from its own pedicle. For the male parts, other fibres are formed into stamina, and from these terminate into apices: and again from these others termi­nate into the minute grains, commonly called the farina fæcun­dans; each grain growing on its own pedicle, just as the leaves or fruits of trees.

See an animal, exactly in the same manner, unfolding itself by degrees, till its parts are explicated entirely, and it is complete in every organ. Then, and not before, each female is capable of producing eggs, each being a continuation of the general organ­ization, and growing upon its own pedicle Each male, likewise, when at its state of perfection, is capable of producing from itself the fecundating matter, necessary for the propagation of the species.

Let us again view a full grown tree or plant, putting forth its parts for fructification. Observe the apices on the stamina, loaded with the globules of the farina fæcundans, the pulp of each globule containing an exalted, fluid, and conveying it to one of the papillæ of the pistil. The utricle is now filled with green, soft seeds, ready to be impregnated by the globule, and con­taining a fluid, which afterward becomes a hard covering to each. And within this the little organization gradually increases.

As then a refined fluid from the seminal matter of the male, impregnates the organization in the egg of a female animal, mingles with the subtle fluids contained therein, and promotes its growth and progress: so the refined part of the pulpy fluid contained in the globule, impregnates the organization in the seed of a plant, mixes with its juices, and gradually promotes its growth into a perfect plant. And doubtless both the impregnating effluvia of animals and vegetables, and the innate juices of the organization, have qualities peculiar to themselves. Hence the offspring of a black and a white parent, is of a colour between both. And thus if the farina of one sort of flower impregnate the egg of another, the colour of the flower produced thereby is variegated proportionably.

The juices imbibed by a plant, being composed of innumerable various substances, after every part has attracted its kindred particles, the superfluous ones are carried off by perspiration: chiefly by the leaves, which are the emunctories, that throw off those juices which have no kindred particles in the plant. Accordingly, when the warm sun begins to rarify the fluids, which during the winter were condensed and inactive, the new leaves then begin to put forth, from their several organizations. When winter comes, as no more fluids ascend in trees, so there is no perspiration. Consequently most of them need leaves no longer, which therefore fall off. Nor are they succeeded by others, till the vegetable begins to receive fresh nourishment, and has occasion therefore for excretory vessels to carry off superfluities. Just so the superfluous juices, in animals, are con­tinually carried off by perspiration: an obstruction of which is equally pernicious to animals and vegetables.

But is there any thing in the vegetable kingdom analogous to that strange animal the polypus, which multiplies by being cut in pieces There is. View, for instance a young willow. This is an organized body, capable of growing, till it comes to its perfect growth by means of the vegetative principle. The polypus is an organized body, capable of being extended till it comes to its perfect growth, and of feeding and loco-motion, by its animating principle. The willow as it grows, is gradually sending off new branches, which are its foetuses, proceeding from the organizations lodged in every part. The polypus, in like manner, gradually sends off new foetuses, from organizations placed in every part of it. If the willow be cut in pieces and planted, each piece will be explicated into a tree, and then send forth new foetuses, like its parent. And if the polypus be cut in pieces, each piece will be explicated into a polypus, and then extrude new foetuses: so that cutting it in pieces, is but antici­pating the propagation of those organizations in the pieces, which would, if let alone for awhile, themselves issue from the sides of the parent.

If we observe the extreme tenderness of this animal, liable to be wounded, nay torn in pieces, by any hard body, which is carried down the streams, or moved in the ponds, wherein they dwell: we see the Providential reason, for this contrivance to propagate them: as perhaps no other animal is of so tender a texture, and so easily destroyed, having neither sagacity to avoid danger, nor strength to bear the least violence.

Other trees have been propagated by a still more surprising way. One having caused some ashen pipes, that had brought water to his fountain twelve years, to be taken up, they were left in the yard, where they rotted almost entirely. But in their’ room there shot up a young forest of ashes, which are now about four feet high. There is no ash-tree within a great distance of the yard..’ Where then were the seeds from which they sprung

24. Mr. Bonet, of Geneva, was inclined to try whether plants would grow, when planted in moss instead of earth, So he filled several garden-pots with moss, and compressed it more or less, as lie judged the several plants might require a closer or a looser soil.

He then sowed therein wheat, barley, oats, and peas. And he found, 1. That all the grains thus sown, came to maturity later than those of the same sorts, which had been sown in mould. 2. That the stems from the seeds sown in moss, were generally taller than those sown in earth. 3. That there came more blades from the . grains sown in moss, than from those sown in the ground. 4. The grains sown in moss produced more’ plentifully than the others. 5. The grains gathered from the corn which grew in the moss, having been sown again, partly in moss and partly in earth, succeeded well in both.

He also planted in’ moss, pinks, daisies, tulips, jonquilles, and several other sorts of flowers. And all these succeeded full as well, as those of the same sort which he planted in mould. He also placed in moss, cuttings and layers of vines, all which grew up into vines. And these in awhile were larger than those which came from cuttings and layers planted at the same time in the ground.

Mr. Kraft sowed oats and hemp-seed in rich earth, in sand thoroughly dried, in shreds of paper, in pieces of woollen cloth, in chopt hay. He afterwards watered them daily, and they grew nearly as well in one substance as in another.

The husbandry of figs, as it.is still practised in many parts, is one of the greatest curiosities in nature. There are two sorts of fig trees, the wild and the garden fig tree. The wild bear three kinds of fruit, fornites, cratitires, and orni: and all these are necessary to ripen the garden fig. The fornites appear in August, and hold to November without ripening. Herein breed small worms, which turn to a kind of gnats, no where to be seen but about these trees. In November these gnats make a puncture in the cratitires, which do not appear till towards the end of Sep­tember, and the fornites gradually fall off, after the gnats have left them. The cratitires remain on the tree till May, and enclose the eggs deposited in them. In May the orni appear, which, after they grow to a certain size are pricked by the gnat issuing from the cratitires.

None of these are good to eat, but only to ripen the fruit of the garden fig tree in the following manner: In June and July, the peasants take the orni, when their gnats are just ready to break out, and carry them to the garden fig tree. If they do not mind the time exactly, the orni drop, and the garden fruit not ripening, for want of its proper puncture, will likewise fall soon after. Therefore they carefully inspect the orni every morning and transfer such of them as are proper. By this means the gar­den figs become ripe, in about six weeks after they have received the puncture of the insect. When they have dried them in the sun, they put them into ovens, to destroy the eggs of the gnats laid in them, from whence otherwise worms would be produced, which would consume the fruit.

What an expense of time and pains is here! Who can but admire the patience of the Greeks, busied above two months in carrying these prickers from one tree to another! But how do. these contribute to the ripening of the garden figs Perhaps by causing the nutricious juice to extravasate, whose vessels they tear asunder in depositing their eggs. Perhaps too they leave with their eggs some kind of liquor, proper to ferment with the milk of the fig, and make it tender. Figs in Paris ripen sooner, for having their buds pricked with straw dipped in oil.