pulation diminishes here daily. At that time the number of inhabitants amounted to 116,000 men; but at prefent we should not certainly find an equal number there. It would be neceffaryto re-establifh harmony in all the orders of the ftate, confounded together. The right of nobility has been taken away by the Genoefe from the moft ancient families, fo thatthere is now fcarce any difference between those who have formerly been gentlemen, and the peafants. There were no more offices, no kind of education for children; and the republic would not admit them to any ecclefiaftical or military dignities. Their new chief has repaired all thefe diforders as well as he was able, that is to fay, he has prevented them from increafing as much as they otherwife would. His precarious authority, ever tottering-his life even every inftant in dangerhave not permitted him to do all the good he wifhed, and of which his genius and wisdom rendered him capable.

As for the reft, you may eafily conceive, Sir, by this account, from whence arifes the invincible hatred of the Corficans against the republic: the latter feenis to have exerted every effort to deftroy these people; they had even forbidden them every kind, of trade annually feized upon their oils and other commodities at a very low price, and made them pay very dear for falt, iron, copper, and the other articles they might want. In a word, they were treated more like favages, whom it was intended to exterminate, than like fubjects who were to be protected. It is to be

hoped that our character of mildnefs, the wifdom of our govern ment, and the goodness of our laws, will repair fo many evils, and will make the new kingdom of Corfica fenfible of the happinefs of living under the dominion of Lewis the well-beloved.

The Prefatory Introduction 10 Scheele's Chemical Obfervatiout and Experiments on Air, and Fire. Written by Sir Torbern Berg man (Knight of the Order of Wafa, Profelor of Chemistry is the Univerfity of Upfal, F. R. S. &c. &c.)

THE fcience of nature feems

to have three degrees. The firit fixes our attention to the out fides, and teaches us to collect external characters, in order to enable us to diftinguish various natural bodies; and this is the proper object of natural history. If we penetrate still deeper by our contemplation, and examine the general qualities of matter (its extenfion, impenetrability and i inertia) in regard to its peculiar relations; it is that which is commonly called natural philofophy

Phyfica). But chemistry is the innermoft part, fince it examines the material elements, their mixtures, and proportions to one au other. The first teaches us the elementary rudiments, the alphabet of the great book of nature; the fecond inftructs in fpelling; and the third, to read diftinctly. The two first therefore are no more than fubfidiary fciences. which conduct us to the laft, as the proper great object.

Since all fingle qualities of

doubt a great advantage, to be able to concentrate the powers of feveral ounces into a few grains. Did we exactly know, after chemical principles, the natural functions going forward in the body, the causes of diseases, and the effects of medicines; chemistry would moft certainly operate miracles.

:

But I foresee already what may be objected to this affertion with fome reason, viz. "Though fuch knowledge would be a moft excellent thing, it would however be rather the object of wishes than fuch as might be fuppofed or hoped for in the human body every operation goes forward very fecretly; nor is there any glafs window to admit the researches of the inquifitive: it is by no means right to play with the lives of men, and it would be highly unjuftifiable to endanger them by uncertain experiments, &c." I reply, this is perfectly right; at the fame time it by no means juftifies us in neglecting the right means of obtaining information; and still lefs in treating them with contempt. Whatfoever is difficult, is not therefore impoffible always. The more investigation and trouble an invention cofts, the more honour may be obtain. ed by it; efpecially if it has for its object, health, the most precious enjoyment a man can be bleffed with. If a man be only poffeffed of a truly fundamental knowledge, many things may be difcovered without the leaft danger. Higher chemistry has difcovered many and various new manipulations, and by recalling to our minds one or the other inftance, we shall be enabled to

judge what more may with reafon be expected.

Several kinds of diseases spread devastation over extensive countries, over people of all ranks and denominations; without being however infectious in themselves. Thefe cannot, properly speaking, be derived from the mode of liv. ing; which in those who are attacked with the evil, is widely different; there must therefore exift a general caufe, which af fects equally the richer and the poorer. The atmosphere is the fame for all; during feveral years its weight and temperature have been obferved; and this has furnished feveral explications, which however are not fatisfactory for the explanation of all its phænomena. Its conftituent parts therefore ought to be better known. The vapours and heterogeneous particles are different in regard to quantity, as well as to quality. Befides chemiftry teaches us, that this elaftic fluid furrounding our globe, is at all times, and every where, a compound of three very different fubftances, viz. of good air, foul air, and aerial acid. The first is called by Dr. Prieffley, if not wrongly, however fome what improperly, phlogisticated air. Mr. Scheele calls it with more rea fon empyreal air (fire air), fince this alone gives life to fire, when the other two kinds of air extin guifh the flame of a candle or fire. The laft kind is commonly called fixed air: but I flatter myfelf to have fatisfactorily proved by experiments, that it is a peculiar acid. The nature of the fir kind, has as yet been very little inveftigated; however by analogy it feems to be hardly any thing

but

but good air, which is corrupted either by a fuperfluity of inflammable fubftance, or perhaps by a want of it. It will however be ftill difficult to decide which of the two above propofitions is the true one. Of these three divifions, the aërial acid always bears the least proportion, and fcarcely makes the fifteenth part of the bulk of the atmosphere, at least on the furface of our globe: the foul air is always in the greatest proportion; and by far more, than the pure or good air.

The various effects of each of these three fubftances upon animal bodies, are ftill involved in impenetrable darknefs. The good air fit for refpiration, ought how. ever to be excellent in its operations, fince without it, it is im poffible to live. It has been be lieved, that it contained an indifpenfably neceffary vivifying food; which never has been provéd, at least it seems not to be of an electric nature. It might per. haps foon be poffible to decide by experiments, whether this good air carries off noxious, efpecially phlogiftic particles; fince the air which has been expired from the lungs, is unfit for refpiration, and is fimilar to that which has been phlogisticated. We fhall then likewife be informed, whether that which makes the greater part of the atmosphere, if it be infpired by itself, becomes fatal, for the reafon that it has been previously faturated with heterogeneous bodies, and is thence incapaciated for carrying off any particles from the lungs. Perhaps the aerial acid becomes an unfit vehicle for these articles, and is itfelf originally formed without VOL. XXIV.

them; however it is not yet afcertained in what manner this air acts; but thus much is certain, that it deftroys all irritability. I have, from animals killed by it, before they were grown cold, extracted the heart, in which it was impoflible to raise the least irritability, either with the most pow erful menftrua, or the fire, or fcalpels. If mufcular fibres were the chief caufe of the motion of the lungs, it would not be diffi cult to find out the ultimate cause of death; but fince its ftructure is formed of quite different fubftances, the greatest difficulties prefent themfelves. By experiments however it might be eafy to afcertain, whether the aërial acid and foul air act in the fané manner. It would therefore be neceffary to investigate, whether irritability (by all appearance fo very neceffary for the whole conomy of animal bodies) is not likewife destroyed in fuch animals as have been fuffocated and killed inftantaneously by that air, which had been corrupted by refpiration, fire, or other means. Since the air returning from the lungs, by expiration, is always blended with aërial acid; it would be neceffary, in order to avoid all ambiguity, entirely to free the foul air of the aërial acid by means of lime-water, before any experiments were made with it. I hope foon to have an opportunity of making them. If then, contrary to expectation, the refult fhews, that they both act in the fame manner, it would feemingly follow from thence, that thefe two fluids, fo very diftin&t in their nature, act however by the fame common unfitnefs, either G

for

for carrying off from the lungs the noxious particles, or introducing into them a vivifying pabulum. But, however noxious aëial acid is for found lungs, it is nevertheless of great utility in the prima via. Purulent lungs not only bear aërial acid, but they are even cured by it: and no fooner is the cure performed, than its inhalation becomes again dangerous. But though there be ever fo much left for investigation, we may apply that for ufe which has already been difcovered. It is for inftance well known, that the air of the atmosphere may be examined in regard to its fitnefs for refpiration; a discovery which bids fair to yield, in a very fhort time, the most important illuftrations. If fuch obfervations were made at the fame time in dwelling-rooms, infirmaries, and the open air, and were continued with fome degree of accuracy, we fhould certainly difcover the caufes of many phænomena, which hitherto have remained inexplicable. Thus much we know already; that wounds and ulcers are with difficulty kept from going into mortification in corrupted, foul air; whereas, on the other fide, the immenfely acute pains accompanying the cancer (that dreadful ailment) are in a few days not only mitigated and affwaged by the external ufe of aerial acid, but the loathfome aperture is alfo confiderably diminished. The compafs of a preface not only prevents me from entering into a fuller difcuffion of this important fubject, but also from producing more inftances of its utility; I cannot help however mentioning in a few words only, that the ob

fervations on aërial acid have al ready fpread a new light on the method of affaying and imitating, by art, medicated waters; and on their application and ufe in the cure of the fourvy, and other internal putrid difeafes. The true analyfis of the calculi from the kidneys and bladder, has enabled us to judge with precision of the beft remedies against the gravel. The discovery of the inner confti. tution of arfenic, made us better acquainted with the manner by which its dreadful effects are produced; and thereby the beft means were pointed out, both to extinguifh its poifonous quality, and likewife to mitigate and di rect its effect for better purposes. -How fimplified are at prefent many compounded remedies; and how fafe and little perilous, are many preparations of the most acrid and corrofive fubftances? How many abfurd mixtures, decompounding and counteracting themselves, have not of late been rejected? How many false theories of difeafes, and their caufes, are there not daily expofed, and fhewn to be without any foundation, by means of chemistry? Sugar was faid to contain lime, in order to account for certain ef fects afcribed to sugar; though it contains not an atom of it. The calculi of the kidneys and the bladder were faid to be calcareous; though they contain at the moft only one half of calcareous fubftance. And fo in many more inftances, which it would be too tedious to enumerate. Laftly, how would it be poffible to discover and to fubject to control the various noftrums, quack-medicines, cheats, neglects, and other monsters of

the