6ih MEMOIR OF LOUIS JACQUES THENAED. 



condition, but 'without any abatement on bis part of heart or hope, Vauquelin 

 at length procured him a tutorship in an institution, and Thenard, though look- 

 ing but remotely to the exigencies of a lecturer's chair, felt the necessity of 

 reforming an accent and gesture which reflected the impressions of his native 

 province. For this purpose, as well as from a veiy decided taste, he attended 

 the theatre as often as his stomach would compromise for an abstinence suffi- 

 ciently long to justify an expenditure of thirty sols. One morning Vauquelin 

 said to him: "I am summoned to Rouen; my course has commenced; you 

 must occupy my place." Unavoidable deliciencies could not but make them- 

 selves perceptible, at the first lecture, to the new professor as well as to his 

 audience, but each succeeding one was marked by so much improvement that, 

 at the fifth, Thenard ventured to cast his eye over the throng and discovered 

 Vauquelin and Fourcroy, in a corner, smiling at his efforts. At the sight he 

 precipitately abdicated the chair. But from that time those eminent men 

 labored in concert for his advancement, and succeeded in securing him an assist- 

 ant professorship at the Polytechnic School. The earliest accession of a little 

 ease and leisure Avas but a signal to Thenard for the institution of original 

 researches. Beginning with 1799, when his first Memoir was presented to the 

 Academy, that body has known him, for more than half a century, to lay before 

 it, several times in each year, the results of inquiries wdiich have formed the 

 basis of striking improvements in science, the arts, and industry. Summoned, 

 one day, unexpectedly and not a little surprised, into the presence of the min- 

 ister of the interior, the latter said to him : "There is a deficiency in the supply 

 of ultramarine blue, Avhich is, besides, always scarce and very dear, and Sevres 

 stands in need of a material which can resist an intense fire. Here are fifteen 

 hundred francs; go and find me a blue which will answer the required condi- 

 tions." Thenard began to stammer an excuse. " I have no time to lose," said 

 Ohaptal, the minister in question, in a petulant tone. "Go and bring me my 

 blue as soon as possible." In a month from that time the rich tints of the 

 beautiful fabrics of Sevres bore witness to the success of the chemist. 



In 1803, Thenard had shown that the supposed zoonic acid Avas but an 

 impure acetous acid, and although Berthollet, then in the zenith of his reputa- 

 tion, Avas the discoverer of this acid, the circumstance produced no change in 

 the generous appreciation «Avhich the latter ahvays manifested for his young 

 competitor. Nor Avas this the only occasion on Avhich Thenard, firm in the 

 expression of his own couA^ctions, Avas called upon to contravene so imposing 

 an authority. When occupied Avith the oxidation of metals, he unhesitatingly 

 maintained the idea of oxides in fixed proportions in opposition to Berthollet, 

 Avho denied it. 



Thenard dcA'oted much attention to organic chemistry, and although later 

 inqiiirers have advanced beyond him, there still remains to his share the merit 

 of having clearly conceived and indicated the relations Avhich connect chemistry 

 with physiology. This science of life rests on an art in Avhich chemistry is 

 pre-eminent, on the high and delicate art of analysis. It was this art Avhich, 

 in its higher and more subtle applications, Condillac first introduced into phil- 

 osophy, and LaA^oisier tells us that he himself derived it from that acute thinker. 



In 1807 appeared researches of great interest on ethers. These, it Avas 

 known, are formed by distilling certain acids Avith alcohol, and this was all that 

 Avas knoAvn. Thenard announced several ncAv ethers; and, yet more, laid a 

 foundation for the theory of these agents, Avhich haA-e already revealed to us 

 some of their surprising effects on life, and doubtless hold in reserve others 

 more STirprising still. 



During this period of engrossing application, Thenard AA^as, early one morn- 

 ing, surprised by a \nsit from Vauquelin. "Up, in all haste," cried the visitor, 

 "and apparel yourself handsomely." Thenard, scarcely aAvake, asks an explana- 

 tion. " The laAv respecting pluralities forces me to resign my chair at the Col- 



