kind, except now and then on the calyx of the leaves; and then I have observed, that the water gets mixed with the resinous juice of the bark, which coagulating bursts the pipes., These hairs are also very different from those which are fixed to the flying seeds, &c., for they resemble the coralines, and the bones of fish; indeed the exact likeness of these three different objects is very striking and curious, They hairs which surround the buds of trees, and are generally wound round them, are never inflated till wanted, and till a certain time in the formation of the bud: when black (as in fraxinus excelsior, juglans regia, and many others), the valves are admirably seen to open and shut in a large magnifier, admitting and passing the water through the black, lines.

their forms

That the hairs alter their forms, I have many proofs. Hairs alter, During great drought I have seen those, which were before plain pipes, swell into divisions between the valves, changing their form from that at e fig. 7, to that at f; and plainly proving the shape of the valves to be as fig. at g. On placing fig.8, Pl. II, in the solar miscroscope, after great bubbling and confusion, I took it out, and found the ribbon changed from the appearance it has at h to that at i. It appeared as if it had been before inclosed in another case, which case had melted away with the heat of the sun, and left the inclosed balls and 'ring uncovered. I have so often seen the same result from repeatedly placing it, that I cannot doubt that this is the case. The divisions k k are often found attached to different shaped instruments, ending sometimes in bells, sometimes in plain pipes; contracted, or inflated, as the occasion re quires. Nothing can be more common than fig. 9, which is always full of water; and fig. 10, which is found on the gas lium aparine. Extraordinary as is all I have related, it is not more wonderful than true. I am the first person that may be said really to have turned the solar microscope on the botanical world; is it then incredible, that I should have wonders to relate? did any person ever take a miscroscope in hand without it?

I shall now turn to the cryptogamian plants, equally taken Description of for perspiration, and described by all botanists as such, the cryptoMany of them resemble the powdered lichens, when they gamian plants,

Fruit known by its various changes ending in seeding.

Innumerable offices the hairs perform.

Different from the armature plants.

to go to seed, though at first appearing like a drop of water, which, even while your eye is on it, turns white, aud soon becomes hard and firm; changing to seed. These are found on the mint, the pea, and innumerable other plants, said to perspire much. That which Hales took for perspiration on the leaves of the sunflower is a sort of mushroom, extremely moist, shown at fig. 11, w; and that on the vine, fig. 12: but I must stop, or my sketches would never end. I observe that the cryptogamian plants on the rose, and many other plants, because red, are allowed not to be perspiration: but surely the proof is not in colour, but on the matter passing from flower to fruit and seed, which all this sort does in a day or two; yielding generally a sort of sirup, and equally nourished by the dews of the atmosphere: and certainly equally unfit with the hairs to be reconed perspiration. I flatter myself therefore, that this will serve to convince those who still doubt.

If I were to mention all the different offices to which the hairs are applied, it would be endless. To catch, convey, and mix, the powder of the stamen with the sirup of the pis til, they are peculiarly adapted, having in each hair a duct for conveying the mixed juices, when melted, to the canal in the pistil. All this is plainly seen, since in the solar microscope each hair is as large as a walking stick. How many various offices do the hairs perform in the corolla, calyx, and stipula! There is one peculiarly appropriated to this latter part, in all diadelphian plants, most curiously formed. How wonderful is the hair in wet plants! placed to guard the air vessels from being filled with insects, they exactly resemble swords, shoot in a circle and meet in the middle of the vessel as at fig. 7. How many an insect and water-fly have I seen run through by them! But this is not all, they have a sort of spring, which makes the hair strike down, and thus get rid of the creature it has threaded. When I give my letter on water plants, I shall show the mechanism of this hair, which is as wonderful as any of the preceding account.

This subject should not be made to interfere with the armature of plants, which is wholly of a different nature, and consists but of two sorts of thorns; the 1st like those of the rose, the acacia, the gooseberry, &c., is formed entirely of

the

the rind, and an excrescence of it; probably arising from an extreme tendency in that part to grow in the same manner as the quercus suber, the ulmus campestris, and many others, the rind of which is a sort of cork, always increasing. The 2d sort of thorn is that which in the cratagus is a disorder in the tree, to which some plants are peculiarly subject: a sort of missed bud, from the stoppage of the line of life, caused probably from the momentary check of the juices, on some sudden alterution of the weather; as I have observed, that, when the barometer and thermometer are without much variation, except the natural one of day and night in the latter, no thorns come out. I have measured at such a time a shoot three quarters of a yard long, without a thorn. But when in the spring alterations are frequent, the branches will be scarce two inches, and always ending in a long one: and on dissecting this, the line of life will be found to have stopped, before any other part of the plant.

duce the

subject more

I intended to give merely a sketch of this subject, till I Hope to introbetter understand how to inflate the hairs with a coloured liquid, and till I can more thoroughly comprehend their uses in detail. and management; for this indeed I should have waited, but that it was absolutely necessary to prove, that I would not have written against the perspiration of plant, without a complete conviction of the truth of my assertion: "that the whole system of perspiration could not be supported against the absolute proof the solar microscope adduces of its falsehood." If I were rich, I would certainly have the instru ments imitated in glass, properly magnified (if it could be done) as I think much might be learnt from it. It is the mechanism of nature: we talk much of its simplicity, but it surely consists only in not making use of more contrivance than is necessary; and when the mechanic powers are wanted, can we do better than study them from models so perfect, forms so wonderful? and though we could not succeed in forming a sort of air pump in a hair; yet it might serve to teach us to simplify our machines, and to rectify many of our mistakes.

Cowley Cottage,

July 29th, 1811.

Your obliged servant,

AGNES IBBETSON.

Inquiry concerning the

II.

Inquiry concerning the Natural Economy of Ants. In e
Letter from a Correspondent.

SIR,

To W. NICHOLSON, Esq.

AVING always observed, since I first commenced faknatural eco- ing your excellent publication, that you have constantly nomy of ants. paid the kindest attention to the inquiries of such as wish to be informed on the interesting subjects embraced by your plan, I feel almost confident of your permission to request, through the medium of your journal, the communication of such original facts and observations relative to the natural economy of different species of ants, as may have occurred to the notice of any of your numerous readers. It appears to me, that, striking as the habits of this genus of insects certainly are, the subject is, as yet, by no means generally well understood.

Your compliance with my request will be considered a particular favour.

I am, Sir,

Your obedient humble servant,

W. H. B.

Speedy alteration of the

stone used for building at Paris

III.

Report of a Committee, consisting of Messrs. Berthollet, Chaptal, Vauquelin, Le Breton, Vincent, and Guyton-Morveau, appointed by the Institute to inquire concerning the Process of the late Mr. BACHELIER, for the Composition of a preservative Stucco.

IT was in 1755 that Mr. Bachelier, struck with the speedy alteration of the stones employed in the principal buildings at Paris, and the inconveniencies of the process employed from time to time to renew their surfaces, proposed to the

Abridged from the Mag Enc. Dec. 1809, p. 241.

super

superintendant of the royal buildings to try a preservative prevented by a stucco. Accordingly three pillars in the court of the Lou- composition, vre were coated with this stucco for half their length, two facing the south, the other the west. These were still remarkable in july last for the uniformity of their tint, strongly distinguished from the dull gray and earthy aspect of the contiguous parts: but as the alterations made in completing the Louvre would necessarily destroy every trace of this experiment, the Institute appointed a committee to inquire concerning it, before it should be too late.

In company with Mr. Fontaine, architect of the Louvre, too thin to inthe gentlemen abovementioned examined the pillars, and jure the finest sculpture, found, that the stucco applied formed a coat too thin to injure the finishing of the most delicate sculpture; that it retained a uniform colour even in the parts exposed to the and unaffected by the weaaction of the wind, rain, and sun; that rubbing it with the ther. -hand made no impression on it; and that, if one of the three pillars exhibited a reddish yellow tint, there could be no doubt, from its appearance in other respects, that this was owing to some colouring matter added intentionally,

It could not be found on inquiry, that Mr. Bachelier Account of it from memory had consigned his process to writing, and the following was by the inthe best account his son could give of it from memory. ventor's son, "Its basis consists of the sifted powder of oystershells, previously washed and calcined to whiteness, mixed with the butyraceous and caseous part of milk. My father used the common cheese known by the name of fromage à la pie [skimmed milk cheese?]. He first separated all the wheyey part by pressure, and then left it fome time exposed to the air to dissolve or soften. In this state he mixed with it a quantity of calcined oystershells in fine powder. When this mixture was brayed on a stone, the cheese softened, and formed a very smooth and whitish liquid paste. To make the stucco he diluted this with a solution of alum in water; the quantity of water being proportioned according to the thickness of the coat intended to be applied."

with it from

Mr. Bachelier could say nothing of the proportions of Paper coated the ingredients, he only added, that, his father having which writing thought of employing this composition undiluted to cover could be ef. leaves of paper, from which writing was easily effaced by a

Wet

faced.