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3*5 Acentnt of a RmarkalL: Establishment 5/"Educstion at Paris.

omed to elude.—The Chevalier, in giving his pupils the charge of themselves, has found how to spare them lies, deceit, and all that apprenticeship of falsehood, to which children use themselves, to avoid constraint, and the arbitrary punishment of their teachers. If there is an opportunity of giving an useful lesson, or a good example, the Chevalier does not fail to make use of it.—A young soldier had been received into the invalids, who had quitted the service with the admiration of his corps. He was carrying bombs, in a garrison that was under siege, for the service of a battery, and had his right arm taken away by a ball, which also wounded one of his comrades. "Poorfellow! (saidhe)was not there alreadymiichief enough done, for you to be spared I" Then causing his load to be put on his left shoulder, he added, that he was bound to serve his country as long as he had an arm left. Paris was resounding with the praises of this young hero, when the Chevalier resolved that the presence of this brave soldier should excite the emulation of his pupils. After having related the tact, he adds, that this hero intended him the honour of dining with him, and that he invited all those of his scholars to meet him whose names were not set down in the registers for any fault; since to deserve to sit in company with a man who had so well fulfilled his duty, the party must never have neglected his own. The Chevalier retires, the council assembles, the registers are consulted, and many of the young people find themselves excluded. Not a complaint, rot a murmur, is heard. They receive the maimed soldier with military honours; he is informed of all that passed; and the Chevalier concludes by saying, that in order to reward the repentance and submission of those who had not been admitted, they might surround the table, and drink his health. It is not probable that this scene will ever cease to be engraved on the hearts

of these young people, or fail to leave deeper impressions than all the precepts of a superficial education.

5. It now remains to give some account of the economical pun of the plan, to which the Chevalier Paulet attaches himself very much: first, because frugality is beneficence; and, in the next place, he has observed, that whatever superfluous expence is retrenched,some vice receives a check. For instance, he has discharged from his house mercenary domestics, a certain source of corruption. The scholars having the care of the house by turns, learn early that useful occupations do not debase any one ; and they themselves buy most of the things for the public wants, which is an apprenticeship of life.— There is no authority or dependence among them but what is reciprocal, and consequently without danger.— Their dress is simple, but neat. In each division there are some who are intrusted with inventories of the linen and furniture, and these give an account to others, who are to examine and see that nothing is lost, and that all that is worn be repaired in time.— Each pupil is committed to the care of another, and when any negligence is observed, they not only blame the one immediately guilty, but him who in quality of inspector ought to take care of him.—The young gentlemen are not exempted from domestic employments ; they preside like the reit over the kitchen, with this distinction, that they do not put their hands to any thing.

When the Chevalier shall have improved his plan, and has in his house the necessary workmen, he will not have recourse to any strange tradesmen.—He has in particular resolved to give a large extent of land for cultivation, and to form a great number of gardeners ; not only to provide them with the resource of an useful occupation, but also to profit by their labour, and sell the productions of his garden in the metropolis. If he is deceived

On the Origin and Nature e/"Pumice-Stone. J t 7

in his calculations, his benevolence a- of his method.—He loves hi? pupils lone has seduced him into ertor. Al- too well not to be beloved by them.1-*ways animated by grand motives, he It was very interesting to observe their Teems to soiget all that he has done, sentiments differing with their ages. to think of what he may yet do. The They had no servile fear, but an ho* execution of his new plans requiring nest confidence animated their looks, adequate means, the king has granted They answer strangers who speak to him the annual sum of 32)000 iivres, them with a modest assuiance. Difto replace the interest of the capital satisfaction is less felt there than in ahe applies to his new buildings, the ny other place of education, because plan of which may serve as a model to the greater part of the youth ate emall establishments of this kind. ployed in what they chuse, and because This worthy man is entirely devo- their studies arc varied with useful reted to the cares of this large family; creations and walks. Their patron in' he thinks and acts only for his chil- terests himself in their amusements as dren. His equipage consists only in well as in their labours. "They mttfl be a little phaeton; and coarse linen and happy (says he) that they may be good." a mean coat compose his apparel. This All the pains he takes to finish what neglect of himself has something mo- he has so nobly begun, become pleaving and great j it shews forgetfulness sures. What pure happiness must this of himself, and a perfect indifference feeling man enjoy in the midst of these for all but his chief object.—Endow- many pupils, to whom, in lieu of mied with great activity, he undertakes scry, dereliction, idleness, vice, and every thing without contusion and with- its dangerous consequences, he gives out noise. He studies all tempers; a happy youth, a Virtuous education, he corrects the defects of youth with industrious habits, an advantageous patience; and encourages those that trade, and returns them back to sodo well by praises, not so much in- cicty, aster having made them good tended to excite self-love* as to ere- citizens!

ate a defire of surpassing themselves. The modesty of this good man is

As for those who do not succeed, he equal to his beneficence. His school,

never puts them to the biuih : "They established these fifteen or sixteen years,

are unhappy enough (fays he) in wans is hardly known at Paris. This ob

ing abiiities and application, and they scurity is his glory ; but it is fortunate

are punished enough by the shame of that he is taken from it, as it is ho

studying under their juniors." A well- ped that so tine an example will not

judged indulgence is the ground-work remain without imitators.

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the light variety of it, and consequently must have had a very imperfect idea of the whole species.

The essential character of pumicestones consists in their being osa white, or of a light-grey colour; in being cf a coarse grain; of a fibrous structure; in having long deep pores with a mining, vitreous, or silky appearance: they are, in general, lighter than the common solid lavas, and much less hard ; they never contain iron ; and it is to the absence of this metal that a part of their properties must be attributed. Moreover, pumice-stones differ from one another in density, solidity, and weight, and they are white In proportion to their levity. They may be divided into four species. The first, which are grey, have a close grain, their pores and fibres are not very obvious, they are of considerable weight and great solidity, and their fracture is somewhat g'assy. These are made use of, as they arc easily wrought, for the corner-stones of houses, and in the construction of walls ; the town of Lipari is almost entirely built of them. The second are likewise grey, but more porous than the preceding species ; their fibrous structure is more distinct, and they are lighter; but still they do not swim in water. They are employed in the construction of vaults, and great quantities of them are exported from Lipari, to be employed in the fame manner in the maritime cities of Naples and Sicily. The third are the light pumice-stones ; these are porous, and of a distinct fibrous texture; they have a silky appearance in their fracture, they swim in water, and, to a tolerable degree of consistence, add a rough grain that makes them proper for polishing marbles and metals: these only are the substances known as pumice-stone in other countries. The fourth species is a very white stone, exceedingly light, of a very loose texture, and of little consistence; it seems to have been driven to the iighest degree of rarifaction that

a substance is capable of, so as still tfl preserve some union among its pans. This variety is of r.o use. When ir falls into the sea, it swims, and is carried to great distances. It is often found on the shores of Sicily, of Calabria, and of Naples. We might peihaps make a fifth species that would comprehend the white ashes of Lipari, which have been formed of the fame fossils rarifieJ by fire, so as to destroy the connection and aggregation of their parts, by which means they receive a fort of volatilization, and are pulverized.

Pumice-stones seem to have flowed In a liquid form like lava, and to have made, like them, great currents, which are found at different depths incumbent upon one another round the groyp of mountains in the centre of Lipari. They are thus heaped up in immense homogeneous masses, on which they always open the quarries for the digging of stones fit for building: the heavy pumice is always undermost, and the lighter above. This arrangement shews another conformity with the currents of ordinary lava, for the porous lavas always occupy the superior pans; and this disposition likewise proves the identity of the nature of these heavy solid pumice-stones with those thai ate lighter, and that have less consistence, and demonstrates their great rarifaction or levity not to be an essential character of the genus: the pumicestones which are in the midst of the allies resemble the pieces of lava, whether compact or porous, that volcanoes throw out in detached masses.

The long fibre of the pumice-stooe is always in the diiection of the current; it depends on the semi-fluidity of this lava which runs to a thread like glass. M. d'Aubenton was tbe first who observed that the silky threads of these light pumice-stones were almost perfect glass. When we find pieces of pumice that have their fibres irregularly bent in every direction, we may conclude that they have been thrown out in detached masses, with* 329

On. the Origin, and Nature s/Tumice-Stone.

eut having been connected with any cuircnt.

It is very singular that the Island of Lipari and that of Vulcano, should be the only volcanoes in Europe that produce the pumice-stone in grcatqu.tr> tity, Etna yields none, Vesuvius very little, and that in detached pieces. It is not found in the extinguished volcanoes of Sicily, of Italy, of France, of Spain, or of Portugal. I acknowledge, however, that I am not well enough acquainted with the productions of Hecla in Iceland, to determine whether our stone is found there. The production of this substance must be attributed to a particular fossil which tolcano-s'seldom meet with, and which must be situated near the fires of these ttfo iflands: we must look for this fossil among the rocks that are destitute of iron, and consequently we mull exclude argillaceous schistus, horn-stone, porphyries, &c. Chalks and white calcareous stones, we may suppose, have furnished it in passing to the state of quick lime strongly calcined; but the fire could never give them the fibrous texture of the pumice-stones ; and, besides, it is not probable that these absorbent substances aie found in the heart of the primary mountains in which the feat of the sire of these volcanoes must be placed.

Being convinced that, in natural history and in natural philosophy, reasoning and conjecture are never to be put in competition with experiment and observation, for the want of which they seldom make amends, I applied myself to study with the greatest attention, and to examine the nature of puraicc-stones on the spot. I attended chiefly to those that are heavy, which, as they seem l«ss altered by the fire, may be presumed to preserve some characters of their primitive basis. I could trace in some of them the grain, the shining scales, and fissile appearance of the whitish, micaceous Ichistus which is found interposed in immense quantity in the midst of the

T

beds of granite that compose the mountains of the Val-Demona. I could perceive in others the remains of granite, in which were still distinguishable the three constituent parts, quartz, feldtspat, and mica ; and I observed that these three substances, which mutually serve as fluxes to each other, acquire by the action of sue, a species of vitrification between that of enamel and porcelaine, and which may be compared to a scoria pretty full of air bubbles (frits line pen bettrsoufflee.) I saw them acquire by degrees the loose and fibrous texture with the consistence of pumice, and I could no longer doubt that the laminated granitical and micaceous rock, and even the granite itself were the principal material* to which, when altered by fire, the formation of pumice-stones ought to be attributed.

These materials which, I suppose, have served as the basis of pumicestones, are not peculiar to the mountains of the Val-Demona, they are found abundantly in those mountains that are called Primary. M. d'Arcet, in his Memoirs on the action of a continued fire, informs us, that the talcs and micas are easily fusible; be tried a granite of Burgundy, which melted while it swelled a good deal in the crucible r this fusion, fays he, is beyond the state of scoria. He found, that a great number of heavy spars melted easily, and accelerated the fusion of other matters. The kaolin, which is made use os at Alengon in the making of earthen ware, is a kind of granite of three component parts, the scoria of which comes very near the state of the heavy pumice-stones. The granites of the Pyrenean mountains, and that which composes the famous pedestal of the statue of Peter the Great, undergo a demi-fusion, and form a grey opake, and sometimes a kind of bloated body according to the force of the fire applied. The granites of the Limonn and la Marchc are very fusible, and more or less resemble the Petunze of

t 2 of

Ejsiiy or. the Irritability of the Sexual Organs of Plants.

33°

os Saint Irie, which is made use of at the manufactory of Seve, where the feldifpat, whch serves a» a flux, contains a portion of clay superabundant to its nature. The scoria of all these granites is white, because they contain no iron; and if they weie ail exposed to a'fire, equal to that of volcanoes, they would produce pumice-stones of different kinds.

To this an objection may be urged, which it becomes me to obviate: Since the materials proper for forming pumice are so frequent in nature, how comes it that the Lipari islands are the only volcanoes that furnish in any quantity this singular production ? It maybe farther objected to me,that there h a contradiction in saying tlsat pumicestone exists almost in a single volcano only, while the greater part of the ancient mountains contain substances capable of acquiring this particular state of porous and bloated scoria which constitutes them, I answer, that it is very seldom that the furnace of a volcano is placed in the midst of granite; it is almost always situated in rocks of argillaceous schist, containing porphyries, petro-silex, flate, schorl, &c. matters which, when operated upon by fire, and much less altered than iB generally supposed, serve as the basis of the ferruginous black and red lavas which are met with in all volcanoes. It ■would appear that these argillaceous rocks contain in abundance, and perhaps exclusively, the combustible substances which maintain the inflammation of the subterraneous fires j the vitriolic acid, and the inflammable principle with which they abound, are perhaps the means made use of by nature

to produce these fires, the existence of which is perhaps a phenomenon as difficult to be accounted for as any other in Nature. I imagine it is owing ta accidental circumstances that the volcanoes of Lipari have found near the scat of their fires considerable strata, or beds of granite, placed amidst the rocks that supply them with fuel, in the fame manner as many beds of granite in the Pyrenees are included in schist and petro-silex. It is certain, that the volcanic fires of Lipaii must be situated in the very point of contact between these different substances, the schists and the granites, as their productions are io distimilar that some of them contain iron, while others are destitute of it. For the production of pumice, it is necessary that the granite be of a nature exceedingly fusible, and that the site of the volcano be more intense and more active than it generally is. The lava that issued from the sides of Etna in the year 1669, and that deluged Catagna, has for its basis a granite which has not been changed, and none of its constituent parts have been altered. This lava, exposed again to the heat of a fire sufficient to fuse to it, vitrifies, and assumes the appearence of an opake scoria somewhat porous, which resembles pumice; a certain proof that a more intense fire in the volcano would have changed that immense torrent of hv» into pumice-stones similar to those of Lipati. The vitreous character of the black lavas of Lipari, the quantity of lapis obsidianus which they contain, evidently shew that the inflammation in those iflands is more intense thai in, the Sicilian volcano,

Exfraft from an Ejsay on the Irritability of the Sexual Organs of Plants*** Read at the Academy of Sciences, by Yl£.Desfontainc8, I'rofesor of Bottnj at Paris.

THE faculty with whioh nature ed Irritability, This power of cou^ has endowed certain bodies of traction, which in animals presents moving, when they are touched, is call- phenomena so various and so aslonifli

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