■ Life of PeKetier. 37 



XI. 



A port Account of the Life of PellkTIER. Read at the Public Sittitig of the National Jnjlitute 

 of France, the i^thVeudemiaire, in the Tear V I. By CiTIZEN LaSSUS, Secretary to the 

 Clafs of Natural Philofophy and Mathematics. 



J N the courfe of the lafl: tilmeftre we have had fhe misfortune to lofe one of our col- 

 leagues, Bertrand Pelletier, born at Bayonne in 1761. His life was confined to the fliort 

 fpace of 36 years ; but his aftions have left an impreffion on the minds of men which time- 

 fhall not efface. 



It frequently happens that young men, fmcerely defirous of inftrudion, have no means 

 or place where they can be aflifted in the development of their natural talents, no mafter 

 who may point out the direft road to fcience, and that order and method without which 

 the efforts of the individual too often lead him from the obje£l: of his purfuit, inftcad of 

 bringing him nearer to it. This was not the cafe with young Pelletier. He found every 

 advantage in his father's houfe, where he received the firfl: elements of the art of which he 

 was afterwards the ornament; and his fubfequent progrefs was made under our colleague 

 Darcet, who having remarked in him that fagacity which may be called the inftinia of 

 fcience, admitted him among the pupils attached to the chemical laboratory of the college 

 of, France. Five years of conftant application and lludy under fuch a mafter, who was 

 himfelf formed by nature, perfe£led by experience, and affeftionately difpofed towards his 

 pupil, afforded this young man a ftock of knowledge very unufual at his age. He foon 

 gave a convincing proof of this, by publifning, at the age of 21, a fet of very excellent ob- 

 fervations on the arfenical acid. Macquer, by mixing nitre with the oxyde of arfenic, had 

 difcovered in the refidue of this operation a fait foluble in water, fufceptible of cryftalliza- 

 tion in tetrahedral prifms, which he denominated the neutral arfenical fait. It is the 

 arfeniate of potafli. He was of opinion that no acid could decompofe it ; but Pelletier 

 fhowed that the fulphuric acid diftilled from it does difengage the acid of arfenic. He 

 fhowed the true caufe why the neutral arfenical fait is not decompofable in doled veffels, 

 and particularly the order of affinity by which the fait itfelf is formed in the diftillation of 

 the nitrate of potafli, and the white oxyde of arfenic. He explains in what refpecls this fait 

 differs from what Macquer called the liver of arfenic. Pelletier had been anticipated in 

 thiswork by Scheele, by Bergmann, by the academicians of Dijon, and by our colleague 

 Berthollet ; but he poffeffed at leaft the merit, in the firfl; effay of his power.--, of having 

 clearly developed all the phenomena of this operation, by retaining arul.even determining 

 the quantity of gas it was capable of affording. After the fame principles it was that he 

 decompofed the arfenico-ammoniacal fait, by fhowing how, in the decompofition of this 

 laft, the pure arfenical acid is obtained in the form of a deliquefcent glafs. In this work 

 we may obferve the fagacity with which he was enabled to develope all the phenomena of 

 thefe compofitions and decompofitions, by tracing thofe delicate threads of fcieniific cou- 

 ne£lion which connedt the feries of fafts, and are imperceptible to ordinary minds. 



Encouraged by the fuccefs of thefe firfl: works, which he.prefented with the fenfibility of 

 grateful attachment to his infl:ru£lor, he communicated his obfervations on the cryft^alliza- 

 tion of fulphur, cinnabar, and the deliquefcent falts ; the examination of 7.eolites, particu- 

 larly the falfe zeolite of Fribourg in Brifgaw, which he found to be merely an ore of zinc ; 

 2 obfervatious 



