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filled above two hundred pages with a collection of obfervations, which may be found, though not indeed in fo many words, in almost every book on the practice of phyfic. His directions for the cure of the disease, though by no means new, are judicious. He difapproves of draftics, and thinks the milder cathartics are not only lefs dangerous, but more efficacious in promoting the evacuation of the water: the diuretics, on which he makes the greatest dependence, are fquills, and millepedes: to the neutral falts he afcribes no great virtue; and is of opinion that fudorifics are not to be given, unless nature fhould indicate an effort to shake off the diforder in this way. He advises an early performance of the Paracenthefis Thoracis; and, from various writers, gives inftances in which it effected a complete cure. His directions for palliating the fufferings of the patient in the laft ftage of the disease, are minute, and indicate an humane perfeverance in the duties of his profeffion, by endeavouring, even to the last moment of life, to alleviate the pains which medicine cannot remove,

Answer to a Question propofed by the Society concerning the Irregu

larities of the Satellites of Jupiter. By the ABBE PAUL RISI, The object of this ingenious aftronomer is to reduce the analytic theories of Meff. BAILLY and LA GRANGE to a more fimple and convenient form, by means of the fynthetic calculus.

Differtation on the most convenient Method of applying M. Volta's

Condenfer to the Purpose of investigating the Electricity of the Atmosphere. By JACOB VAN BREDA, M. D. Member of the Philofophical Societies of Rotterdam and Utrecht.

After trying several fubftances, both fimple and compound, for his electrical condenfer, Dr. BREDA found that nothing anfwered this purpose better, than a plate of gyp, or plaifters of Paris, the furface of which was covered firft with linfeed oil applied boiling hot, and afterward with a very thin coat of vari nith. The apparatus, by which this inftrument is applied to examine the electricity of the atmosphere, is here minutely defcribed, and the defcription illuftrated with a plate. It is fufficient to obferve that, by means of a wire, or wet packthread, the upper plate of the condenfer muft be connected with a pointed conductor of lightning, which fhould be at fome distance from any building, and be, at leaft partially, infulated; a fmall wire muft connect the conducting plate of the condenfer with a ftand, on which, under a glafs receiver, are two electrometers; the one with a graduated arch like that of Mr. Henley, but more light and fenfible, the other conftructed of a fingle thread and pith-ball. From the obfervations made with this apparatus, it appears that the electricity of the air, during a thunder-ftorm, was much oftener found to be negative than pofitive.



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Memoir on the following Question, "What must be thought of that gradation, which many philofophers, both ancient and modern, have fuppofed to take place among natural Beings; and what degree of certainty can we acquire concerning the reality of this gradation, and the order which nature obferves in it ?" By J. A. DE LUC, Reader to the Queen of Great Britain.

We have been particularly careful to give a literal tranflation of this queftion, from the programma of the Society, because the directors inform us in a note, that this memoir being deemed unfatisfactory as an answer to the prize queftion, the gold medal was not adjudged to its author: that a filver one however was prefented to him, on account of fome very good things contained in it; and that it is here printed in a smaller letter, not as an answer, but as a differtation.

By thus publishing this memoir, the directors have obliged the world at their own expence; for, with all due respect be it faid, they have exhibited a ftriking inftance of their own fallibility. If this memoir be not an answer, nay, if it be not a very accurate and decifive anfwer to their question, we know, not what the Society can deem fuch. The Directors now tell the world, that they required an answer deduced from natural hiftory, and give us to understand that they reject this, because it is metaphyfical. But this limitation is not expreffed in the terms in which the queftion is propofed; befide, M. DE LUC has very plainly proved that it is a metaphyfical proposition, and cannot be accurately answered in any other way. This we think will fully appear from a fhort account of the memoir, for which, we are certain, our philofophical readers will deem themselves obliged to us.

The question, as here propofed, fays M. DE Luc, is addreffed to the philofopher. The naturalift claffes natural beings as they are perceived by man, and, from him, the philofopher must receive his firft leffons. Without facts, there can be no philofophy. But to reduce facts under general heads, to eftablish fundamental principles for the examination of particular theories, to forefee what future improvement we may expect in fcience, is beyond the province of the mere naturalift; this is the talk of the philofopher. The question, as here stated, relates not to minute difquifitions, nor to facts, nor to fyftems of phyfiology; but folely to the fyftem of fome philofophers, who conceiving only abftract ideas of beings, fuppofed it either neceffary or fit, that they should be connected with each other by an infenfible gradation.

The question is naturally divided into two parts, each of which is here feparately confidered; but M. DE LUC judicioufly inverts the order in which they ftand, and examines, in the first part of his memoir, whether fuch a gradation can really


be inferred from obfervations already made, and whether, by continuing thefe obfervations, we may expect to difcover, with certainty, the actual exiftence of this gradation.

The diftribution of natural bodies into three diftinct kingdoms is one of the firft ideas that occurs; but this, which might be fuppofed fimple and eafy, is attended with uncertainty, from the difficulty of exactly determining the line which separates each of thefe kingdoms from the other. If we are ignorant of the mechanifm of nature in the formation of fome of those beings, which appear to be intimately related, on what shall we found our determination that no line of boundary can be drawn between them? If we know that, in confequence of more accurate observations, the mineralogift and the botanist have been enabled to decide their refpective claims, concerning several of thofe beings which had contributed to this uncertainty, what reafon can we have to deny the existence of such a boundary? And fince a greater degree of knowlege has, in many inftances, removed thefe difficulties, which hence appear to have been owing to ignorance, why fhould we maintain, that a ftill greater degree of knowlege, if attainable, may not enable us to define the exact limits of each of the three kingdoms of nature?

The boundary which feparates the animal from the vegetable kingdom, appears exceedingly uncertain. Some plants offer more figns of life than certain beings which are confidered as animals. But is it not poffible that thofe, in which we obferve fuch figns of life, may really be animals, and that these, which appear lefs animated, may really be plants? This question at once deftroys the fuppofed continuity of the chain of beings; for a fyftem, which can be fupported only by our ignorance, has properly no foundation at all.

The intermixture of characters among different fpecies of the fame kingdom, has also been urged in fupport of the gradation in queftion. There are men, we are told, who appear to be inferior in rational and moral character to fome of the brute creation. And are we hence to conclude, that there is fuch an infenfible gradation from the man to the brute, that no exact line can be drawn between them? But, in this instance, it will not be pretended that the human fpecies is compared with any fpecies among the brutes; the utmoft that can be inferred from it, is the refemblance of fome individuals to each other, and even this inference is extremely fallacious, because founded merely on external appearances.

Let us fuppofe that fome accident deprives a man of memory, or reduces him to a state of idiotifm. Are we acquainted with the caufe of this change? Do we know whether that, which, in other men, is the principle of memory or of judgment, is deftroyed in him; or whether it may not be only an alteration of


fome external part, that difables him from exerting these faculties, though they ftill exift? Now if thefe faculties ftill exift in him, though reduced to a ftate of inactivity; if they exift even in one born an idiot, though concealed by fome defect of. organization; there can be no real refemblance between thefe individuals of the human fpecies, and the moft perfect fpecies among the brutes, because none of the latter ever had those faculties, which man in a healthy ftate difplays. Accidental circumftances may alter the appearance of man, but cannot change his nature: and it is the real nature of beings that must be confidered, in order to form any well-founded determination concerning their rank in the universe.

It is further urged, that a great degree of confufion is obfervable among fpecies generally confidered: the mineralogift, the botanist, and the zoologift, find it not lefs difficult to fubdivide their kingdoms, than to define their several boundaries. The leaft attention to thefe ftudies, fhews the infufficiency of all our fyftems, with refpect to the diftribution of the beings of each kingdom into claffes exactly defined. But thefe fyftems are the effort of art, to fupply the defects of our memory and the narrow limits of our capacities; true fcience must be acquired by contemplating the objects themselves. The philofophical naturalift, who will not be fatisfied with a mere nomenclature, will at length confine his attention to the fpecies. Those beings, in which all the apparent characters are alike, be will arrange under the fame fpecies; of thofe, in which he obferves any new characters, however faintly the fe may appear, he forms new fpecies; nor will the number of these difcourage him; because he knows that, in this way alone, he can acquire juft ideas of nature: by purfuing this method, he will avoid the want of diftinction fuppofed in this argument; the caufe of which must be fought, not in the nature of the objects, but in our inattention to form a fufficient number of diftinct fpecies, under which they may be arranged.

From these principles, M. DE Luc judiciously concludes that an infenfible gradation of beings is not, and cannot be, demonftrated by arguments à pofteriori: because all observations, in proportion to their accuracy, have a tendency to afcertain and define diftinctions; but the difference of character, on which thefe diftinctions are founded, must be perceptible in order to be discovered; and where no such differences can be difcerned, we have reason to conclude that there is, not gradation, but uniformity.

In the fecond part of his memoir, the ingenious author examines the queftion itself, and inquires, whether arguments à priori can be advanced to juftify the fuppofition of an infenfible gradation of beings. He obferves, that atheists are un



worthy of a philofophical answer, because their fyftem, if fuch it can be called, is founded on no philofophical principles. He therefore conftitutes Theifm, as the foundation on which his reafoning depends. This fundamental principle at once evidently diffolves that continuity, which an infenfible gradation fuppofes; for, whatever perfection we may afcribe to any created being, the diftance between the creature and the Creator muft ftill be infinite. Hence we are neceffitated to confider the idea of an imperceptible gradation as relative only to created beings; but here a very obvious diftinction arifes between fome which are endued with fenfation, and others, which are infenfible. Against this divifion no objection can be urged à pofteriori, because it is founded on obfervation; neither can it be argued à priori, that God could not create beings void of fenfation, or that infenfibility is incompatible with exiftence. Is it then poffible to conceive that thefe two claffes are connected with each other, without a folution of continuity? Senfibility and infenfibility are qualities directly contrary, which, therefore, neceffarily exclude each other: the difference between two beings endued with fenfibility, the one in the higheft, the other in the loweft poffible degree, is nothing when compared with the difference between the latter and an infenfible being. A difference in degree is always finite, but a difference in nature is infinite.

In the class of infenfible beings, we diftinguifh the vegetable from the mineral kingdom: between thefe, there is a very obvious folution of continuity. A vegetable is an organized being which propagates its kind. Every being therefore of this clafs, is produced from one or two beings like itfelf: it is at first fmall, and, from its organization, grows to a larger fize. A mineral is a being produced individually by fome phyfical caufe, very different from itself, and, therefore, cannot produce its own kind. If thefe definitions of the vegetable and mineral be juft, the difference between them is abfolute. A being either is, or is not, organized for the purposes of propagation. The reality of this diftinction is not affected by our inability to apply it in all cafes for if we could difcover any infenfible beings, which, without entirely belonging to either of thefe kingdoms, had the diftinguishing characters of both (which the Author confiders as impoffible), we should only difcover a new kingdom, as diftinct from the former, as these are from each other: for it cannot be maintained that fome common properties can conftitute this pretended continuity, where there are, at the fame time, other properties entirely diftinctive.

M. DE LUC proceeds to fhew that, in each kingdom, the feveral fpecies are really diftinct from each other, and obferves that their difference becomes evident, if we define each species


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