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any hilling, they will bed themfelves at that distance from the furface of the ground which gives them the greateft advantage to procure nourish-, ment; this deptu, I have obferved, is generally about four inches, and this. depth, the plaut finds by fomething which I will venture to call inft net, it feems to be fo much I ke, but in a lower degree, that principle, or rather faculty, in the lowest order of the brute creation.

If the earth in which you plant potatoes should be hard, and not yield to the preffure of the roots, it will then be neceffary to hill them, but great care should be taken not to earth them too much, never let them be covered above four inches, and this hilling muft, be given with difcretion, for if they have bedded themselves (as they will in mellow, land) four inches, and you add four inches more earth, you fuffocate the fruit.Take an example; potatoes, just before they bloffom, begin to form their bulbs, if you leave them now, the fruit will grow rapidly, but if you fhould add earth to the hill the young bulbs (for want of that air that can pervade four inches of earth) willperifhand others will fprout above, them; this will be the progress of nature, fo long as you continue to bur, den them with earth .Therefore, to procure an early crop of potatoes, be fure, to give them your last earth as foon as the plant is big enough to receive it, when they know (excufe the mode of, expreffion) you have left earthing them they will begin to vegetate and increase with great rapidity,but will not while you keep burdening and flifling them. Thus much (at prefent)as to the culture, a word relative to the time of gathering this crop maft conclude this effay. Every production of the earth. has its time of maturity, confequently the potatoe, if you harveft them before they are ripe, the juice will be crude; they will be unpleasant to the tafte and will not keep fo well as if fuffered, to grow longer; the fign of ripenefs in this fruit, is the turning and fading of the leaf and thrinking of the talk. It is remarkable in almost all bulbous, roots, especially the onion and potatoc, that they receive their hrt nourish ment from the root, and finish their growth by what they receive from the, top. I hope this will be received with

candor, as the time allowed me was very fhort, if this should be acceptable, you may perhaps hear further from

AGRICOLA.

On Education.

HAT menin the original con..

Tfitution of their minds, are nearly

upon an equality, has been afferted, by fome of the greateft men, who have. written in ancient or modern times. This was the opinion of Mr. Addifon, who feems to have ftudied human nature, and wrote with clearness, and precifion, upon every fubject, about which, he has employed his pen. Similar were the fentiments of the late Lord Chesterfield, who, in a peculiar manuner, made man his particular ftudy. I would not have it thought from thefe obfervaions, that I conceive there exifts a perfect equality in the rational powers of every individual of the human fpecies; for it must be plain, that there are, among our race, eminent and towering ima ginations, which as far exceed, in fublimity of fentiment, the common level of mankind, as there are bills and mountains in the natural world, rearing their lofty heads above the neighbouring plains. Thefe fublime fpirits imbibe the dews of heaven, and impart their bleffings to the country which they inhabit, and hence, become as ufeful to their fellow men, as, thofe mountains are, in beftowing fertility to the foil below them. But, would it not be as unreasonable to say that, because the land, in the neighbourhood of mountains, produced in much greater abundance, than that, at a diftance from fuch a fituation, that therefore, the hand of cultivation was not useful, in affifting the earth in general? And would it not be equally abfurd, to affert, that because there were to be found, here, and there, in the courfe of a century, men of uncommon genius, who were enlightned as it were, with a ray from heaven, to inftru&t and illuminate the age, in which they lived, that therefore, it was neceifary, for mankind to attend. to the rudiments of letters, or exert themselves in the education of youth.

That there is a confiderable fimilarity of mental powers, among men, is prets ty certain, notwithfunding the forego.

ingremark.We have feen men,of fo fu perior natural talents to their brethren who, from the circumftance of lofing a Jeg or an arm, or fome other bodily in jury, have been obliged to apply themfelves to the fludy of books, making very confiderable improvements in literature, and becoming able statesmen, skilful phyficians, eminent lawyers, or learned divines, who would have remained but for thefe feeming misfortunes, unknowing and unknown.

The utility of education, is a point which feems to be fo well eftablished, that it must appear, to thofe unacquainted with the prefent ftate of it, in the commonwealth, to be unneceffary fo ufe any arguments, to perfuade the inhabitants into a fenfe of its imporfance. But, to what caufe can it be attributed, that the country have neglected their ancient, laudable inftitution of grammar fchools? If the war was the fole caufe of this regle&, now that is over, why, in the name of good fente, can they emit this very important concern any longer? can they be contented, to have their children wanting in that knowledge, which is neceliary to preserve their freedom? Can you, ye inattentive parents! fee the more enlightened part of the community, with all their affiduity procuring the neceffary inflruction for the chidren, to render them emiment, and useful, and perhaps (though at present it may be foreign to their views) to make their children tyrants of your heirs; and maflers of that property which you have procured with labour and toil? And will you not take the only flep to prevent the confequences, which naturally attend fuch exertions?

I may not fuppofe the neglect of fur porting grammar fchools can be the effe& of parfimony; men, who have been excited to a fenfe of freedom, by the medium of that inftruction, the foundation of which was firft laid in the inftitution of grammar fchools, can never withhold from their offspring, the fame means of inftruction which was the bans of their own freedom and independence.

It will not do to perfuade your felves, or be perfuaded, that private academies will prove fufficient for the diffufion of knowledge. I am how

ever, ready to acknowledge the grea advantages enjoyed in private academies, by thofe pupils who have the good fortune, to be born of fuch parents or connected with fuch patrons, who have the ability, and inclination to procure fuch inftruction for thofe under their care, for these, under the tutelage of men of great ability and felected from the literati for this exprefs purpose, muft, like the intervale in the neighbourhood of the moun tains alluded to above, fhare largely, of that fertility, acquired by fuperior genius and eminence. However, fuch is the fituation of much the greater part of this land, indeed of every community, that it cannot be expected, that many can receive fuch peculiar advantages.

I knowit has been faid, that had not private academies been infiituted in the time of war, the fpirit of education would have been abolished. This feems to be begging the queflion; [ grant, that during the war, from a great variety of extraordinary causes, the zeal and attention to town fchools, remitted, in many places; but, had there been no such inftitution as aca demies, men of wealth and influence, would probably have procured inftructors in their respective towns.

The flate of Connecticut have, with great good fenfe, attended to this inftitution of schools, in all their towns, fo that at this feafon of the year, when our fchools in the country, were formerly but little frequented, a traveller can fcarcely pafs through a town in that fate but he observes the fchools thronged and generally attended by youth of both fexes. This intelligence I have from a gentleman, who has lately been through a great part of that country, and made the above remark, with that pleasure, which we fhould expect the fight would produce, in the mind of a true republican. But my fellow countrymen! fhould you continue your negligence and inattention, to this important inflitution in your advanced age, you may fee the Laurels of your youthful days wither on your brows; your filver locks may bow in cheifance to a tyrant's mandate, and your aged fhoulders may bend beneath a load impofed by fome haughty mafter. Defcription

Defcription of Experiments made with the Aeroftatic Machine, invented by Meffieurs De Montgolfier,&c.-From the Appendix to the fixty-ninth Volume of the Monthly Re

view.

E avail ourfelves of this op. portunity to lay before our readers a brief, hiftorical account of the very interefting difcovery which has of late attracted the notice of the

whole philofophical world ; and which our fanguine neighbours did not fcruple, at the very firft, to dignify with the name of AERIAL NAVIGA

TION.

Although the Author of this book be known to have warmly efpoufed the party of Montgolfier, in oppofition to that of Charles (for there are parties even concerning Balloons) yet his reputation, as a man of learning and veracity is fufficiently established, and the facts he here alledges are in general, as we have had opportunities to afcertain by collateral evidence, Rated with fufficient accuracy to juf tify us in taking him for our guide in

this narrative.

The Preface contains a fhort furvey of what projects have formerly been fuggefted for the purpofe of floating heavy bodies in the atmofphere; the principal of which are thofe of Lana, a Jefuit of Brefcia, and of Galien, a Dominican of Avignon, both which however were, upon well enablished principles, found by theory to be m poffible in the execution*. Due honour is paid to Mr. Cavallo of London, who, in 1732, feemingly with a view to this difcovery, tried to fill bags of paper and bladders with inflammable air; but failed in his attempts, by the unexpected permeability of paper to inflammable air, and the too great proportional weight of the common fized bladders. Had he then thought of employing gummed filk, or gold.

The impoffibility of Lana's projea was demonftrated by Hook; fee his Philofophical Collect ons, No. I. P. 28. And fince by Leibnitz. Gali en's never needed any confution.

beater's fkin, he probably would have plucked the very laurels that now adorn the brews of Montgolfier and Charles.

I. The honour of the difcovery is

certainly due to the brothers Stephen and Jofeph Montgolfier, proprietors of a confiderable paper manufacture at Annonay, a town in the Vivarais, about thirty fix miles fouth of Lyons: and their invention is the more to be adm red, as it is not the effect of the late difcovery of a permanent elaftic fluid lighter than the common are, but of properties of matter long known, and in the hands of the many acute philofophers of this and of the last century. They conceived that the effect they looked for might be obtained by confining vapours lighter than common air, in an inverted bag, or covering, fufficiently compact to prevent their evaporation, and fo light, that when inflated, its own weight, added to that of the inclosed vapour, might fall fomewhat short of the weight of the air which its bulk difplaces.

On thefe principles, they prepared matters for an experiment. They formed a big, or balloon, of linen cloth, lined with piper, nearly (pherical, and meafuring about 35 ferg in diameter *, its folid contents were about 22,000 cubic feet, a fpace nearly aqual to that occupied by 1980 lb. of common air, of a mean temparature, on the level of the fea. The vapour, which, by conje&ure, was about half as light as common air, weighed 990lb. The balloon, together with a wooden frame fufpended to the bottom, which was to ferve as ballaft, weighed 490lb. whence it appears that the whole muft have been about 500 lb. lighter than an equal bulk of common air. This difference of specific gravity, by which thefe bodies are made to rife, we shall henceforth, without warranting the propriety of the expreffion, call their power of afcenfion."

The 5th of June 1783, was fixeď on for the difplay of this fingular experi

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320 ment. The States of Vivarais, who were then affembled at Annonay, were invited to the exhibition. The flaccid bag was fufpended on a pole 35 feet high; ftraw and chopped wool were burst under the opening at the hottom; the vapour, or rather fmoke, foon inflated the bag, fo as to diftend it in all its parts; and,on a sudden,this immenfe mafs afcended in the air with fuch a velocity,that in lefs than ten minutes it appeared to be about 1000 toifes above the heads of the spectators. A breeze carried it about 1200 to fes from the fpot whence it departed; and then the vapour, either efcaping thro' fome loop holes that had been accidentally left in the conftruction, or being condensed by the coldness of the circumambient air,the globe defcended gradually on a vineyard, with fo little preffure that none of the flakes were broken,and carce any of the branches of the vines bent.

Experiments made with the Aeroftatic Machine?

II. The rumour of this fuccefsful Experiment foon reached the metro polis, and roufed the emulation of the Farifian philofophers. Without waiting for particular inftructions from the inventors, they reflected on a me. thed of their own; and refolved, inRead of vapour, to use inflammable air; the specific weight of which, when pure, they knew to be to that of common air nearly as ten to one *.

The procefs of producing this a'r, being very expensive, the author of the book now before us, fet on foot.a fubfcription; and having foon raised a fufficient fum, M. CHARLES, Profedfor of experimental philofophy, and and M. ROBERT, a mathematical infrument maker, were fet to work: and they conftructed a globe of luteAring (affetas) glazed over with, elaftic gum diffolved in fome kind of fpirit or effent al oil. After many difficulties and difappointments, which will ever attend firft,effays, they fucceeded, in two days, to fill this globe with inflammable air, produced from 1000 lb. of iron filings, and 498 lb of vitriolic' acid, diluted in four times its quantity

We munere at leaf commemorate the name of Cavendish; to whom it is acknowledged on all hands, the difcovery of the fpecific gravity of inflammable air, as well as of many other of its propertics, is folely due.

of water. This globe measured 12 feet 2 inches in diameter, its folid contents were 943 feet 6 lines cubic, and its power of afcenfion was found equal to 35 lb.

The 27th of Auguft 1783, having been fixed on for the exhibition of this experiment,the balloon was conveyed, in the preceding night floating in the air, from a court near the Place des Victoires, where it had heen conftrufted, to the Champ de Mars. Our author indulges Lis lively imagination in a lofty defcription of this nodurnal proceffion, which, he fays, moved along in the dead of night, attended by a party of guards, with lighted torches, and feemed fo awful, that the hackney coachmen who happened to be in its way, defcended from their feats, and devoutly proftrated themselves before the fupernatural being that advanced in fuch folemn flate.

The concourfe of people, on foot and in carriages, was fo immenfe in the Champ de Mars, that a large body of troops were drawn out to prevent difturbances. At five o'clock in the after noon, a fignal having been given by the firing of a mortar, the cords that confined the globe were cut, and it rofe, in lefs than two minutes, to a height of near 500 toifes. there entered a cloud, but foon appeared again, afcending to a much greater height; and at laft it was loft among other clouds.

It

Our Author juftly cenfures the conduct of this experiment; observing that too much inflammable air, and that even fome common air had been introduced into the globe, which being clofed on all fides, left no room for the expanfion of this elaftic fluid when it fhould arrive to a more rarified medium. We find, in fae, that it muft have burft in confequence of this expansion; fince, after having floated about three quarters of an hour, it fell in a field near Gonefs, a village about fifteen miles N. N. W. of the Champ de Mars. It must be allowed, that the mere evaporation of the air could not well have been the cause of its defcending fo foon. Many periodical papers have already entertained the public with ludicrous accounts of the aftonishment of the peasants who found it, and of the rough treatment it received at their hands.

III. It

III. It may easily be imagined, that thefe brilliant fucceffes annimated the zeal of all the curious in the metropolis; and that many effays were made to repeat the fame experiments upon a fmaller scale.

Our author, accord

ingly, in a third chapter, mentions a number of these fecondary attempts; upon which we fhall dwell no longer than only to observe, that they fucceeded with globes made of gold-beater's skin; and only 12 inches in diameter, which being thought the least that could be made to afcend, confidering that the proportionate weight of the materials increase as the bulk is diminifhed, were called minimums.

IV. M. Montgolfier junior, having arrived at Paris a few days before the experiment at the Champ de Mars, was defired by the royal Academy of Sciences to repeat the experiment of Annonay. He accordingly conftru&ed, in a garden, in the Fauxbourg St. Germain, a balloon of an elliptical form, 70 feet high and 40 feet in diameter. It was lined both infide and outfide with paper. Its power of afcenfion was found, upon calculation, to be about 1250 lb. it was filled in ten minutes by the burning of 50 lb. of ftraw and 10 lb. of chopped wool. It was loaded with a weight of 500lb. and afcended, faftened to ropes on the 12th of September, in the prefence of the deputies of the Royal Academy. But it proving a very rainy day, the whole apparatus was fo effentially damaged, that it was not thought proper to let it loofe.

V. We come now to the experiment made on the 10th of September, in the prefence of the King and Queen, the Court, and all the Parifians who could procure a conveyance to Verfailles. This balloon was 57 feet high and 41 in diameter. Its power of afcenfion, allowing for a wicker cage, containing a fheep, a cock, and a duck, which was fufpended to it, was equal to 696 lb. As only four days had been allowed for making this machine, it could not. therefore, be lined with paper. M. M. had predicted, that it would remain in the air about 20 minates; and, with a moderate wind, might float to a d.ftance of about 2000 toiles. But, belides fome imperfection in the conftruttida, owing to the great hurry in which it had been made, a

fudden guft of wind, while it was inflating, made two rents feven feet long near the top, which could not but in fome measure prevent the promised effect. It fwelled, however, in 11 minutes fufficiently to raise it above 240 toifes; it floated to the diftance of nearly 1700 toifes; and, after having been in the air about eight minutes, it fubfided gradually in the wood of Vaucreffon. The annimals in the cage were fafely landed. The fheep was found feeding; the cock had received fome hurt on one of his wings, probably from a kick of the fheep: the duck was perfeâly well.

VI. M. Montgolfier determined now to repeat the experiment under more favourable circumftances, and more at his leifure. He, therefore, made a new balloon, in a garden, in the Fauxbourg St. Antoine, which measured 70 feet in height, and 46 feet in diameter. A gallery of wicker was contrived round the apperture at the bottom; under which an iron grate or brazier was fufpended, and port-holes opened on the infide of the gallery, towards the aperture, through which any person cui robur et æs triplex circa pectus fuerit, who might venture to afcend, might feed the fire on the grate, and thus keep up the vapour, fmoke, or as we rather apprehend, the dilitation of the air, in this vaft cavity.

On the 15th of October, M. Pilatre deRofier, no doubt the most intriped philofopher of the age, placed himself in the gallery, afcended about 80 feer from the ground, and there kept the balloon afloat for fome time, by repeatedly throwing ftraw and wool upon the fire. In this experiment it was found, that the descent of a globe (provided no extraordinary accident happened to it) muft neceffarily be gradual; and that it will always light foftly upon the ground, fince, in fact, in every part of its defcent it enters a denfer medium; whence its velocity in falling, will rather be retarded than accelerated. On the 19th of October, M. P. de R. afcended a fecond time, about 250 feet. After continuing fiationary about eight minutes, a guft of wind carried the balloon among fome trees, where it intangled itfelf fo as to indanger its being torn to pieces. But.

M. Charles

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