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filled above two hundred pages with a collection of observations, which may be found, though not indeed in so 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 disapproves of drastics, and thinks the milder catharties are not only less 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 ascribes no great virtue ; and is of opinion that sudorifics are not to be given, unless nature should indicate an effort to shake off the disorder in this way. He advises an early performance of the Paracenthesis Thoracis; and, from various writers, gives instances in which it effected a complete cure. His directions for palliating the sufferings of the patient in the Jaft ftage of the disease, are minute, and indicate an humane perseverance in the duties of his profession, by endeavouring, even to the last moment of life, to alleviate the pains which medicine cannot remove. Answer to a Question proposed by the Society concerning the Irregu

larities of the Satellites of Jupiter. By the ABBE PAUL FRISI.

The object of this ingenious aftronomer is to reduce the analytic theories of Meff. Bailly and LA GRANGE 10 a more fimple and convenient form, by means of the synthetic calculus. Dissertation on the most convenient Method of applying M. Volta's

Condenser to the Purpose of investigating the EleEiricily of the At. mosphere. By JACOB VAN BREDA, M. D. Member of the Philosophical Societies of Rotterdam and Utrecht.

After trying several substances, both fimple and compound, for his electrical condenser, Dr. BREDA found that nothing answered this purpose better, than a plate of gyp, or plaisters of Paris, the surface of wbich was covered firtt with lioleed oil applied boiling hot, and afterward with a very thin coat of varnith. The apparatus, by whicb this inftrument is applied to examine the electricity of the atmosphere, is here minutely described, and the description illustrated with a plate. It is fufficient to observe that, by means of a wire, or wet packthread, the upper plate of the condenser must be connected with a pointed conductor of lightning, which should be at fome distance from any building, and be, at least partially, insulated ; a fall wire must connect the conducting plate of the condenser with a stand, on which, under a glass receiver, are two electrometers; the one with a graduated arch like that of Mr. Henley, but more light and sensible, the other constructed of a fingle thread and pith-ball. From the observations made with this apparatus, it appears that the electricity of the air, during a thunder-storm, was much oftener found to be negative than positive.



Memoir on the following Question, "What must be thought of that

gradation, which many philosophers, both ancient and modern, have supposed 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 observes in it." By J. A. De Luc, Reader to the Queen of Great Britain.

We have been particularly careful to give a literal translation of this question, from the programma of the Society, because the directors inform us in a note, that this memoir being deemed unsatisfactory as an answer to the prize question, the gold medal was not adjudged to its author : that a silver one however was presented to him, on account of some 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 said, they have exhibited a striking instance of their own fallibility. If this memoir be not an answer, nay, if it be not a very accurate and decisive answer to their question, we know not what the Society can deem such. 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 metaphysical. But this limitation is not expressed in the terms in which the question is proposed; beside, M. De Luc has very plainly proved that it is a metaphysical propofition, and cannot be accurately answered in any other way. This we think will fully appear from a short account of the memoir, for which, we are certain, our philosophical readers will deem themselves obliged to us.

The question, as here proposed, says M. DE Luc, is ad. dressed to the philosopher. The naturalist classes natural beings as they are perceived by man, and, from him, the philosopher must receive his firft lessons. Without fa&ts, there can be no philosophy. But to reduce facts under general heads, to establish fundamental principles for the examination of particuJar theories, to foresee what future improvement we may expect in science, is beyond the province of the mere naturalist; this is the talk of the philosopher. The question, as here stated, relates not to minute disquisitions, nor to facts, nor to systems of phyfiology ; but solely to the system of some philosophers, who conceiving only abftract ideas of beings, supposed it either necessary or fit, that they should be connected with each other by an insensible gradation.

The question is naturally divided into two parts, each of which is here separately considered ; but M. de Luc judiciously inverts the order in which they stand, and examines, in the first part of his memoir, whether such a gradation can really


be inferred from observations already made, and whether, by continuing these observations, we may expect to discover, with certainty, the a&ual existence of this gradation.

The distribution of natural bodies into three diftinét king. doms is one of the first ideas that occurs; but this, which might be supposed Gimple and easy, is attended with uncertainty, from the difficulty of exactly determining the line which separates each of these kingdoms from the other. If we are ignorant of the mechanism of nature in the formation of some of those be. ings, 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 consequence of more accurate observations, the mineralogist and the botanist have beco enabled to decide their respective claims, concerning several of those beings which had contributed to this uncertainty, what season can we have to deny the existence of such a boundary? And since a greater degree of knowlege has, in many instances, removed these difficulties, which hence appear to have been owing to ignorance, why should 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 separates the animal from the vegetable kingdom, appears exceedingly uncertain. Some plants offer more figns of life than certain beings which are considered as animals. But is it not posible that those, in which we observe such figns of life, may really be animals, and that these, which appear less animated, may really be plants? This question at once deftroys the supposed continuity of the chain of beings; for a fyftem, which can be supported only by our ignorance, bas properly no foundation at all. · The intermixture of characters among different species of the fame kingdom, has also been urged in support of the gradation in question. There are men, we are told, who appear to be inferior in rational and moral character to some of the brute creation. And are we hence to conclude, that there is such 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 species is compared with any species among the brutes; the utmoft that can be in ferred from it, is the reiemblance of some individuals to each other, and even this inference is extremely fallacious, because founded merely on external appearances.

Let us suppose that some accident deprives a man of memory, or reduces him to a state of idiotism. 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 dedro, ed in him ; or whether it may not be only an alteration of


fome external part, that disables him from exerting these faculties, though they still exift? Now if these faculties still exist in him, though reduced to a state of inactivity; if they exist even in one born an idiot, though concealed by some defect of organization; there can be no real selemblance becween these individuals of the human species, and the most perfect species among the brutes, because none of the latter ever had those faculties, wbich man in a healthy ftate displays. Accidental circumstances may alter the appearance of man, but cannot change his nature: and it is the real nature of beings that must be considered, 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 observable among ipecies generaily considered : the mineralogift, the botanist, and the zoologist, find it not less difficult to Tubdivide their kingdoms, than to define their several boundaries. The least attention to these studies, thews the insufficiency of all our systems, with respect to the diftribution of the beings of each kingdom into classes exactly defined. But these systems are the effort of art, to supply the defects of our memory and the narrow limits of our capacities; true science must be acquired by contemplating the objects themselves. The philofophical naturalist, who will not be satisfied with a mere nomenclature, will at length confine his attention to the species, Those beings, in which all the apparent characters are alike, he will arrange under the same species; of those, in which he observes any new characters, however faintly these may appear, he forms new species ; nor will the number of thele discourage him ; because he knows that, in this way alone, he can acquire just ideas of nature : by pursuing this method, he will avoid the want of diftin&tion supposed in this argument; the cause of which must be fought, not in the nature of the objects, but in our inattention to form a sufficient number of distinct species, under which they may be arranged.

From these principles, M. de Luc judiciously concludes that an insensible 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 ascertain and define diftinctions; but the difference of character, on which these distinctions are founded, must be perceptible in order to be discovered; and where no such differences can be discerned, we have reason to conclude that there is, not gradation, but uniformity.

In the second part of his memoir, the ingenious author examines the question itself, and inquires, whether arguments à priori can be advanced to justify the supposition of an insenuble gradation of beings. He observes, that atheifts are un



worthy of a philosophical answer, because their fyftem, if such it can be called, is founded on no philosophical principles. He therefore conftitutes Theism, as the foundation on which his reasoning depends. This fundamental principle at once evidently diffolves that continuity, which an infenfible gradation fupposes; for, whatever perfection we may ascribe to any created being, the distance between the creature and the Creator must still be infinite. Hence we are necessitated to confider the idea of an imperceptible gradation as relative only to created beings; but here a very obvious diftinction arises between fome which are endued with sensation, and others, which are infenfible. Against this divifion no objection can be urged à pofteriori, because it is founded on observation ; neither can it be argued à priori, that God could not create beings void of sensation, or that insensibility is incompatible with exiftence. Is it then possible to conceive that these two classes are connected with each other, without a solution of continuity ? Sensibility and insensibility are qualities dire&tly contrary, which, tberefore, necessarily exclude each other : the difference between two beings endued with sensibility, the one in the highest, the other in the lowest poffible degree, is nothing when compared with the difference between the latter and an insensible being. A difference in degree is always finite, but a difference in nature is infinite.

In the class of insensible beings, we diftinguish the vegetable from the mineral kingdom : between there, there is a very obvious folution of continuity. A vegetable is an organized bring which propagates its kind. Every being therefore of this class, is produced from one or two beings like itself: it is at firft small, and, from its organization, grows to a larger size. A mineral is a being produced individually by some physical cause, very different from itself, and, therefore, cannot produce its own kind. If these 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 cases : for if we could discover any insensible beings, which, without entirely belonging to either of these kingdoms, had the diftinguishing characters of both (which the Author confiders as impoffible), we should only discover a new kingdom, as diftinct from the former, as these are from each other : for it cannot be maintained that some common properties can conftitute this pretended continuity, where there are, at the same time, other properties entirely diftinctive.

M. de Luc proceeds to shew that, in each kingdom, the several species are really diftinct from each other, and observes that their difference becomes evident, if we define cach species


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