9 o THE POPULAR SCIENCE MONTHLY. 



Linnaeus found botany a chaos and left it a rigid science ; yet 

 Linnaeus acknowledged his system to "be artificial. "Artificial 

 classes," says he, "are a substitute for natural till natural are 

 detected," thus anticipating the better method in a riper time ; 

 and by a curious coincidence in the very year of his death, 1778, 

 Antoine Laurent de Jussieu began writing his Genera Plantarum, 

 which contained the proposed classification. 



The honor of the invention of the natural method belongs to 

 Bernard de Jussieu, who made use of it in the arrangement of the 

 garden of the Trianon in 1759, rather than to his nephew, An- 

 toine, who elaborated, perfected, and published it. The classifica- 

 tion of the Jussieus was more philosophical than that of Linnaeus, 

 and eventually superseded, but did not destroy it ; it arose rather 

 as a superstructure upon Linnsean foundations, and built along the 

 lines which Linnaeus had already marked out. The Genera Plan- 

 tarum has been characterized by Cuvier as a work " which per- 

 haps forms as important an epoch in the sciences of observation 

 as the Chimie of Lavoisier does in the science of experiment." 



Antoine Laurent de Jussieu's Genera was scarcely finished be- 

 fore Paris ran mad. It was the time of the Revolution. Happily 

 for him that his profession as physician kept him busy in the hos- 

 pitals and out of public life during these terrible days ! The com- 

 parative obscurity of his life at this time allowed him to safely 

 pass through the bloody ordeal which destroyed equally inno- 

 cent and noble-minded men. There was no head which the guil- 

 lotine cut off that could not have been better lost than that of 

 Lavoisier. 



Black, Cavendish, and Priestley, in England, and Scheele, in 

 Sweden, had been making invaluable discoveries in chemistry, 

 but chemistry was still in disorder. Lavoisier's mental equip- 

 ment placed him at the fore-front of the scientific experimenters 

 of his day, and there was no one so well qualified to perform his 

 chosen work in chemistry as himself. 



In 1778, in a memoir to the Academy of Sciences, Lavoisier 

 questioned the existence of " phlogiston," and attributed to oxy- 

 gen the acidifying principle. A second memoir, in 1784, on the 

 analysis of water, confirmed his position. In conjunction with 

 other French chemists, he substituted for the cumbersome chemi- 

 cal terms a nomenclature of such scientific accuracy that, with 

 slight modifications, it continues to the present day. Its way thus 

 prepared, his Traite* eldmentaire de Chimie, which contained his 

 innovations and came out in 1789, proved a death-blow to the 

 phlogiston doctrines, and prepared the way for modern chemistry. 

 A chemist of such qualifications was very naturally called into 

 requisition by the state. He increased the explosive quality of 

 gunpowder, devised a system of weights and measures, and served 



