'6$ Analysis of vegetable and animal substakces. 



X. ■ 



'Abstraet of a Memoir on the Analysis of Vegetahle and Animal 

 Substances : by Messrs. Gay-Lussac awdTHENARD*. 



i^ingvegeu.;-^"^ KEN we conceived the design of studying the ana- 



bleandani- lysis of animal and vegetable substances, the first idea that 



mal sub- occurred to us was, to convert, by means of oxigren, vegetable 



stances. " i • , i • o '. o 



and animal substancesintowarter,carbonic acid, and nitrogen: 



and on this we fixed our attention. It was evident, that, if 



we could effect this conversion so as to collect all the gasses, 



this analysis would attain very great accuracy and simpli- 



DifficuUies, 'City. Two obstacles appeared in the way of this : first, 

 the burning of the hidrogen and carbon of these substances 

 completely; and, secondly, the effecting of this combustion 

 in close vessels, 



Mnthodsof -yfjg f*,,j5j. we could hope to surmount only by means of 



obviating ^ ; ... 



them. metallic oxides, that easily part with their oxigen, or of the 



hyperoximuriate of potash. A few trials soon led us to pre- 

 fer this salt, which succeeded beyond our expectations. It 

 was far from being so easy to surmount the second: for 

 we could not attempt the combustion in a retort filled with 

 merqury ; since the retort would have burst, had we burned 

 ever so little in this way. It was necessary therefore to cbn- 

 "^^^.P^^g^^"^ '■®* trive an apparatus, in which we could 



1st, Burn parts of a substance so small, that the vessell^ 

 should not crack : 



2dly, Effect such a number of combustions successively, 

 that the results h.- u;d be very perceptible : and 

 ,3dly, Collect the gasses as they were formed. 

 Dftscnptioncf An npparatus of this kind we lay before the class^ It id; 



in apparatus; foyj^e^] of three separate pieces. One is a tube of very thick 

 answering . , • r r • ' i- 



tljese purposes, glass, hermetically sealed at the louver end, and open at the 



upper; about 2 dec. [7*87 in.] long, and 8 mil. [3*15 line^] 



in diameter. This has a very small tube, likewise of glass, 



. .^^-.. . . "similar to what would be adapted to a retort to receive gas- 



' ■' - ses, joined laterally to it by means of the blowpipe 5 centr 



* Ann, de Chim. Vol. LXXIV, p. 47. Read to the InstUute thfe' 13th 

 ofJaauaty, 18}0, .. i ,. i,,. 



' ■ [1-97 in.] 



