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within him in the midst of the intellectual activity of Paris, and the 

 intention of returning to Champagne was abandoned. Thenard' s 

 ability as a teacher, and his power of elucidating science with a kind 

 of dramatic effect, suggested, it is said, by witnessing the performances 

 of Talma, induced Vauquelin to obtain for him the appointment of 

 Repetiteur at the E'cole Poly technique, where he first became ac- 

 quainted with Gay-Lussac. This happened about the year 1798. 

 Soon afterwards, Vauquelin deputed him to deliver some chemical 

 lectures for him at the E'cole Poly technique, celebrated then, as now, 

 for the ability of its lecturers. In this task he was eminently suc- 

 cessful, notwithstanding the disadvantage of a strong Champagne 

 dialect, which he overcame with difficulty. About this time, being 

 twenty years old, his labours, for which the E'cole Polytechnique 

 opened a field, attracted the attention, and earned the applause of 

 Laplace and Berthollet. The'nard's first publication, a memoir on the 

 combinations of antimony with oxygen and sulphur, appeared in 

 1800. Guyton de Morveau, one of the Commissioners appointed 

 to report upon it to the Institute, declared they recognized in 

 M. Thenard, at that time only twenty-three years of age, a chemist 

 practised in the most delicate manipulation, and possessed of all the 

 means of promoting the science, and that he ought to be encouraged 

 in a career upon which he had entered with such success. In 1801 

 M. Thenard obtained sebacic acid by submitting to distillation various 

 fatty substances. He discovered a new method of making cerusse, 

 which was carried into practice by Hoard; also a blue pigment, known 

 by his name, obtained by igniting hydrate of alumina with arseniate 

 or phosphate of the oxide of cobalt, and a very simple and practical 

 method of purifying oils and rendering them more fit for the pur- 

 poses of illumination. This process has been used on an enormous 

 scale for more than the third of a century. He was the first chemist 

 who devised a process for estimating with accuracy the quantity of 

 carbonic acid present in atmospheric air, by agitating the air with a 

 solution of baryta. In 1802 Thenard was appointed to fill the Chair 

 of Chemistry at the College de France, vacant by the retirement of 

 Vauquelin, who recommended Thenard as his successor. About the 

 same period he became one of the ordinary Professors of the E'cole 

 Polytechnique, and may be considered to have fairly established 

 himself on a level with the most eminent men of his time. From the 



