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fufficient, alone, to affign the place, which human nature ought to hold in this grand scale."
The thirteenth book treats of the researches and observations relative to the planets and the progrefs of aftronomy, fince the difcoveries of Newton, or from the year 1687 to 1730. The fourteenth contains researches relative to comets and ftars, and the progrefs of aftronomy during the period last mentioned.
This volume is terminated by M. BAILLY's discourse concerning the nature of luminous and obfcure bodies in the univerfe, and a vocabulary defigned to explain certain astronomical terms, which may escape the knowledge of numbers, whom the beauty, perfpicuity, fcience and amenity, that jointly adorn this excellent work, will engage to peruse it.
AR T. VII.
Lettres du Docteur DEMESTE, Correfpondant de la Societé Royale de la Medicine, au Docteur Bernard, &c. Sur la Chymie, &c.-Letters concerning Chymiftry, Chriftallography, Decimafticks*, Lithology, Mineralogy, and Natural Philofophy in general, addreffed to Doctor BERNARD, firft Profeffor of Phyfic at Douay, and Fellow of the Royal Society of London, by Dr. DEMESTE, Correfpondent of the Royal Society of Medicine, &c. with this Infcription: Novus rerum nafcitur ordo. Vol. I. Paris. 1779.
HESE letters are the production of a mafterly writer, and an accurate obferver.-Perfpicuity and precision, method and order, diftinguish the manner in which the Author expreffes his ideas; but his difcuffions, like many others of modern times, fhew us, that phyfical theories are as little afcertained, and are not a whit more fufceptible of evidence in the analytic line, than metaphysical ones.
The title fhews the kind of entertainment, which the philofophical, and more especially the chymical Reader, is to expect in thefe letters. The firft difcuffion we meet with turns upon elementary fubftances, among which fome will be furprised to find, neither fire, nor air, as our Author adopts the hypothesis of Sage, confiders these as mixed bodies, of which the former (compofed of phlogiston and elementary acid) contributes to the formation of the latter, by a combination with the aqueous principle. You fee, gentle Reader, how far the air is from being an element, or fimple principle, upon this hypothefis; it is fo far from being fimple, that it is a double-compound. This notion is illustrated and confirmed with great fagacity and depth of reasoning in three of the letters that compofe this volume, to which we refer the curious Reader.
These elements, which we ftill look upon as dusky beings after all these illuftrations, lead our Author to treat of affinities,
* A new French term for experimental chymistry, and more especially mineralogical experiments.
another phenomenon, that has been fometimes gently bending the tongues and pens of our phyfical theorifts towards the profound language, that procured veneration to occult causes fome centuries ago. It is the doctrine of M. de Buffon, whofe genius is of the comprehenfive and combining kind, that the laws of affinities are the fame with that general law by which the celeftial bodies act upon each other, and that they (affinities) exert their powers in the fame proportions of maffes and diftances. Sage, in the year 1773, compofed a table of affinities upon this principle of gravity; but a farther obfervation of M. de Buffon, if it be true, renders this principle inadequate to the phenomena, and confequently uncertain and ambiguous: the observation is, that figure, which in the celeftial bodies has little or no influence on the law of their action on each other, because their distance from each other is great, has an extenfive influence, and does almost all, in the affinities between bodies, whofe diftance from each other is fmall or null. Now this obfervation difconcerts the hypothefis of fpecific gravity; for if the degrees of affinities depend abfolutely upon the figure of the conftituent parts of bodies, these degrees muft, like the figures, vary ad infinitum, even where the fpecific gravities are the fame. The different operations of different falts on various fubftances, and the different cryftallizations, that are obvious to the eye of an attentive obferver, will not permit our Author to call in queftion this obfervation of M. de Buffon. He affirms, nevertheless, that our perfect ignorance of the figure of the conftituent parts of bodies, which the philofopher of Paris has been fo gracious as to acknowledge, obliges us, in our enquiries after the causes of particular affinities, to confine our researches to the different proportions and relations which take place between the specific gravities of the particular fubftances. That is to fay-we do not know the true caufe; and therefore muft take up with fuch a caufe as we can come
Simple affinity is the tendency of two homogeneous bodies to mutual union and cohefion, and the more that the fubftances are homogeneous, the more powerful is the cohesion or attraction; nor, according to our Author, can there be any affinity between two heterogeneous fubftances, unless a third fubftance intervene, which has fomething analogous to, or in common with, them both. It is thus that oil and water may be united by the intervention of an alkali:-It is true, continues our Author, that we frequently fee fubftances, that do not appear to us at all homogeneous, blended together, with eafe, in the most perfect union; but, on clofe inquiry, it will be found, adds he, that thefe fubftances have fome parts that are analogous to each other, and even homogeneous, though in all their other parts they are heterogeneous in the highest degree. Such are the APP. Rev. Vol. lx. diffolvents
diffolvents and chymical menftruums, which act palpably on fubftances with which they feem to have no analogy; but no menftruum, according to our Author, can diffolve a substance, with the principles of which it has no fort of analogy or homogeneity; and if acids act in this manner upon metals, it is because the phosphorus, which is the principle of metallifm (if we may ufe that term), contains an acid.
The relation, then, of analogy or homogeneity, that different fubftances have with their menftruums, and these latter with their fubftances, is what the Chymifts more especially diftinguish by the name of affinity, and the different degrees of this relation seem to be derived from the laws of gravity. Our Author therefore treats the fubject of affinity, thus defined in its nature, and determined in its degree, by reducing it to two general laws, ift, the relation or analogy of different menftruums to the fame substance; 2dly, the relation of different fubftances to the fame menftruum. The detail into which our Author enters in the illuftration of these laws is methodical, clear and interesting, and it occupies the first ten letters of this volume.
In the eleventh and twelfth he treats of aeriform fubftances, which are known, at prefent, under the denomination of gas. We find under this article, the relation of a fact, which proves, in a very striking manner, the anti-feptic quality of fixed air or the mephitic acid. At Latera (fays our Author), near Bolfena in Italy, a goat which had died in the vapour of a non-inflammable moffet, was obferved to remain found and entirely exempt from putrefaction during the space of five or fix months.
In the two following Letters DR. DEMESTE treats of phofphoric and faline fubftances, with his ufual fagacity; and then proceeds to lithology, or the history of stones. Linnæus was the firft who perceived that there can be no cryftallization without a faline principle, and therefore ranged cryftallized stones in the clafs of falts. Sage generalized ftill farther the idea of Linnæus, and being convinced by the analytic procefs, that all the earths and ftones of which our globe is compofed, refult from a combination of one or more acids with an alkaline or terreous bafis, he concluded from thence that they must be real, faline mixts, though void of taste and favour, and almoft all indiffolvable in water*. M. Romé de L'Ifle, by his cryftallographical obfervations, has also confirmed this hypothefis, and fhewn the analogy there is between falts and ftones. Our Author adopts the divifion, made by M. Sage, of lithology into fix claffes, but
Our Author fays almost all,-for the gypsum or plafter stone, of which there are fuch immenfe quarries, is really, notwithstanding the general opinion, fufceptible of folution in a large quantity of
does not arrange ftony fubftances in thefe claffes in the fame manner with that famous mineralogift.He defcribes with the greatest accuracy all the cryftals hitherto known; his defcriptions, indeed, are not accompanied with figures, but he makes amends for this by referring the Reader to those which are to be found in the plates of M. Romé de l'Ifle's excellent effay (as it is modeftly called) concerning cryftallography. These figures our Author points out exactly, and they are of great ufe in the perufal of thefe letters, in which the Reader will find new afpects of the proceedings of nature in this branch. Besides, the utility of these cryftallogical researches will appear greater than may be imagined at firft fight, when it is confidered, that they furnifh confequences and refults, which explain the formation of thofe rocks of the granit kind, which the most celebrated naturalifts, at prefent, confider as a mafs that fuftains all the other rocks known to us. This part of the work before us is particularly curious, and in no other does the Author appear more master of his fubject.
Upon the whole, the principles of M. Sage appear under the pen of our Author to more advantage than they do in his own writings; they are unfolded with more perfpicuity and extent, and affume the air of a fyftem: the phosphoric acid acts here a capital part; it forms the bafis of metals, precious ftones, the fluor fpars, and is the principle of vitrification, according to Meffrs. Sage and Demefte. It cannot be denied that certain appearances favour thefe opinions, fuch as the zinc's yielding a flame, the diamond's exhibiting a flame alfo when exposed to a hot fire, the fufible fpath's yielding a phosphoric flame, when thrown upon burning coals, and the fixed alkali's producing glafs with quartz: nevertheless the doctrine of these ingenious men will require farther proofs and experiments, in order to its complete cftablishment on the ruins of former opinions.
The second volume of this work, in which nature is to be confidered in her different aspects, mineral, vegetable, and animal, is in the press, and a speedy publication is announced.
Penfieri intorno a vari Soggetti di Medicina Fifica e Chirurgica, &c.— Thoughts concerning different Subjects of a Medical Kind, that have a more immediate Connection with Chirurgery and Natural Philofophy, in Three Differtations, by DR. FRANCIS BERLINGHIERI, Profeffor of Medicine, &c. in the University of Pifa. 8vo. Lucca. 1778.
T often happens, that after a laborious application to the ftudy of the theory of medicine, a fagacious and learned physician is at a lofs in regard to the ufe and application of those remedies, whofe effects are the moft fully afcertained, and which are the
moft frequently employed in the art of healing. This uncertainty is partly owing to the ftill prevailing ignorance of feveral of the moft minute and effential parts of the animal economy, and which has engaged our Author to confider (in the first of thefe differtations) the obstacles to the improvement and progress of the practice of phyfic, that arife from the mechanism of the human body, and the erroneous methods of studying it. In treating this delicate and difficult fubject, DR. BERLINGHIERI fteers with fagacity and judgment between the credulity of the medical bigot, and the folly and impertinence of the medical fceptic. He acknowledges his ignorance, and that of his brethren, with refpect to many objects, in which the poor patient believes them enlightened, and trufts in them with an implicit faith, and a foolish face of admiration and confidence; and he is not ashamed to advance the following propofition, fo humiliating to the fons of Efculapius, that the numerous and ftriking difcoveries in anatomy, fo much celebrated in the laft and prefent centuries, have not, as yet, contributed in the leaft to the progrefs and improvement of medical practice. He unveils, in a great many refpects, the defects of medical fcience; and, though he may do real fervice to truth by this modefty and candour, he takes away much illufory comfort (ftill it is comfort) from the fick, who look up to their medical Popes, as clothed with infallibility, and cooperate fuccefsfully with them in the cure, by the effects of this confidence. He obferves particularly, that the indications derived from the fenfible qualities of the blood and the motions of the pulfe, are by no means fure guides, either with respect to the knowledge of the nature or caufes of diseases. And after many reflections of this kind, relative to the theory and practice of phyfic, he proposes fome attempts to correct the noxious qualities of the air in unhealthy places, and more especially in that district of Tuscany which is known under the denomination of Maremmes; and concludes his differtation by a judicious plan for directing the ftudies of the medical youth in the hospitals.
The fecond Differtation is thus entitled: Concerning the natural and morbific Fire of the human Body, and certain Difeafes which are produced by it. DR. BERLINGHIERI demonftrates, or, at leaft, proves, that in the human body, while alive, there is an inflammation of a peculiar character, which, when it does not exceed a certain degree, nourishes life and health,-that this inflammation, and the heat that refults from it, are not produced by the friction which the fluids meet with in paffing through their tubes-that this inflammation augments confiderably in thofe parts where the tumour (called inflammatory) is engendered-that this inflammatory tumour can only form itfelf in the nervous parts, and confequently has never its feat in the membrana adipofa, or cellular fubftance, which is, on the contrary, very frequently