Essays Physical and Chemical; By M. Lavoisier, Translated from the French, with Notes, and an Appendix, by Thomas Henry (Paperback)

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER II. Of Mr. BOYLE's ARTIFICIAL AIR. WHAT Van Helmont called Gas, Boyle denominated artificial 4ir. Furnifhed with the new inftruments with which he has enriched Natural Philofophy, he repeated all Van Helmont's experiments in Vacuo, in condenfed Air, and in open Air. The greater part of his Experiments may be found in a work entitled Coniinuatio novorum Experimentorum pbyfico me- cbanicorum de gravitate et elatere eeris. Some others are difperfed in many parts of his works. - Boyle was fenfible, as well as Van Helmont; that moft vegetables, when diluted with a certain proportion of water, and placed in a fitua- tion proper for fermentation, difcharge a con- fiderable quantity of Air; that this Air dif- charges itfelf with more facility in the exhaufted Feceiver of an Air pump, than in compreffedAir; that every thing which impedes the pro- grefs of fermentation fufpends alfo the feparation of the air, and that fpirit of wine poflefles this property in a particular and eminent degree. These experiments, repeated in air much more condenfed than that of the atmofphere, afforded nearly the fame refults. He then tried the effect of placing the fermenting matter in an atmofphere of artificial air, and he found that in fome circumftanccs it accelerated, and in others retarded the fermentation. But one eflencial difference, between this air and that of the atmofphere, before obferved by Van Helmont and recognifed by Boyle, is that the latter is ncceflary to the e.xiftence of many animals, whereas the other, when breathed by them, proves inftantly deftructive. Mr. Boyle's experiments on this fubject demonftrate that artificial air is not always the fame, from whatever vegetable fub- ftance it may be feparated; and that the air which is produced by the explofion. of gunpowder...