SCIENTIFIC ACQUISITION.
The composition of the revolutionary spirit. -- Scientific acquisition its first element.
On seeing a man with a somewhat feeble constitution， but healthy in appearance and of steady habits， greedily swallow some new kind of cordial and then suddenly fall to the ground， foam at the mouth， act deliriously and writhe in convulsions， we at once surmise that this agreeable beverage contained some dangerous substance； but a delicate analysis is necessary to detect and decompose the poison. The philosophy of the eighteenth century contained poison， and of a kind as potent as it was peculiar； for， not only is it a long historic elaboration， the final and condensed essence of the tendency of the thought of the century， but again its two principal ingredients have this peculiarity， that， separate， they are salutary， and in combination they form a venomous compound.
I.SCIENTIFIC PROGRESS.
The accumulation and progress of discoveries in science and in nature. - They serve as a starting-point for the new philosophers.
The first is scientific discovery， admirable on all sides， and beneficent in its nature； it is made up of masses of facts slowly accumulated and then summarily presented， or in rapid succession. For the first time in history the sciences expand and affirm each other to the extent of providing， not， as formerly， under Galileo and Descartes， constructive fragments， or provisional scaffolding， but a definite and demonstrated system of the universe， that of Newton.[1]
Around this capital fact， almost all the discoveries of the century， either as complementary or as prolongations， range themselves. In pure mathematics we have the Infinitesimal Calculus discovered simultaneously by Leibnitz and Newton， mechanics reduced by d'Alembert to a single theorem， and that superb collection of theories which， elaborated by the Bernouillis， Euler， Clairaut， d'Alembert， Taylor and Maclaurin， is finally completed at the end of the century by Monge， Lagrange， and Laplace.[2] In astronomy， the series of calculations and observations which， from Newton to Laplace， transforms science into a problem of mechanics， explains and predicts the movements of the planets and of their satellites， indicating the origin and formation of our solar system， and， extending beyond this， through the discoveries of Herschel， affording an insight into the distribution of the stellar archipelagos， and of the grand outlines of celestial architecture. In physics， the decomposition of light and the principles of optics discovered by Newton， the velocity of sound， the form of its undulations， and from Sauveur to Chladni， from Newton to Bernouilli and Lagrange， the experimental laws and leading theorems of Acoustics， the primary laws of the radiation of heat by Newton， Kraft and Lambert， the theory of latent heat by Black， the proportions of caloric by Lavoisier and Laplace， the first true conceptions of the source of fire and heat， the experiments， laws， and means by which Dufay， Nollet， Franklin， and especially Coulomb explain， manipulate and， for the first time， utilize electricity. - In Chemistry， all the foundations of the science： isolated oxygen， nitrogen and hydrogen， the composition of water， the theory of combustion， chemical nomenclature， quantitative analysis， the indestructibility of matter， in short， the discoveries of Scheele， Priestley， Cavendish and Stahl， crowned with the clear and concise theory of Lavoisier. - In Mineralogy， the goniometer， the constancy of angles and the primary laws of derivation by Romé de Lisle， and next the discovery of types and the mathematical deduction of secondary forms by Haüy. - In Geology， the verification and results of Newton's theory， the exact form of the earth， the depression of the poles， the expansion of the equator，[3] the cause and the law of the tides， the primitive fluidity of the planet， the constancy of its internal heat， and then， with Buffon， Desmarets， Hutton and Werner， the aqueous or igneous origin of rocks， the stratifications of the earth， the structure of beds of fossils， the prolonged and repeated submersion of continents， the slow growth of animal and vegetable deposits， the vast antiquity of life， the stripping， fracturing and gradual transformation of the terrestrial surface，[4] and， finally the grand picture in which Buffon describes in approximate manner the entire history of our globe， from the moment it formed a mass of glowing lava down to the time when our species， after so many lost or surviving species， was able to inhabit it. - Upon this science of inorganic matter we see arising at the same time the science of organic matter. Grew， and then Vaillant had just demonstrated the sexual system and described the fecundating of plants； Linnaeus invents botanical nomenclature and the first complete classifications； the Jussieus discover the subordination of characteristics and natural classification. Digestion is explained by Réaumur and Spallanzani， respiration by Lavoisier ； Prochaska verifies the mechanism of reflex actions ； Haller and Spallanzani experiment on and describe the conditions and phases of generation. Scientists penetrate to the lowest stages of animal life. Réaumur publishes his admirable observations on insects and Lyonnet devotes twenty years to portraying the willow-caterpillar； Spallanzani resuscitates his rotifers， Tremblay dissects his fresh-water polyps， and Needham reveals his infusoria. The experimental conception of life is deduced from these various researches. Buffon already， and especially Lamarck， in their great and incomplete sketches， outline with penetrating divination the leading features of modern physiology and zoology.