ABSORPTION Ofc" NITROGEN. 4'3 



readily decompofed than the falphuret of potalh, and is 

 confequently better adapted for the purpofe of expedition. 

 In raoft of the experiments, the abforption was finidied in 

 about twenty minutes, if fufficient agitation had been, em- 

 ployed. The only objedion, to which the above teft may It does not ap- 

 feem. liable, is, that, according to fome, it abforbs a fmall P-';^°„'"°'*' 

 proportion of the nitrogen, as well as the oxigen of the at- 

 mofphere. This opinion, however, does not appear to be 

 well founded, for in feveral of pur experiments, where the 

 quantity of oxigen abforbed appeared to be unufually fmall, 

 and where the agitation was continued for a much longer' 

 time than necetfary, no perceptible alteration in the bulk of 

 the air was obferved *. 



The method of proceeding in the analjfis of the air^ was Theprocefs. 



briefly as follows ; after having; afcertained the purity of the '^'■^^'""^ ^^- 



■i . *=• tr J ami nation of the 



atmofpherical air by means of the eudiometer above-men- air, 



tioned, and knowing the exa6l bulk of the air contained in (he 

 gafometer, the total quantities of oxigen and hidrogen in it 

 were calculated by a very fimple procefs. This air was then 

 refpired, and its diminution marked as has been already de- 

 fcribed. After refpiration, a portion of it was introduced ^^-^ afff re- 

 into the eudiometer, and its carbonic acid was abforbed by 

 means of lime water, (for which the above-mentioned in- 

 flrument was found extremely convenient). Freed from the 

 carbonic acid, the air was now fubjefled to the aftion of the 

 fulphuret of lime, and the relative quantity of nitrogen con- 

 tained in it was thus difcovered. Then, by deducting the 

 quantity of carbonic acid, and of oxigen gas, contained in 

 the air of refpiration, from the total quantity that remained 

 after refpiration, we procured the proportion of nitrogen, 

 which abftracled from the total quantity before refpiration, 

 gave the proportion of nitrogen abforbed, Tlius, let g re- 

 prefent the original quantity of nitrogen ; /' the carbonic'acid, 

 and c the oxigen of the air of refpiration, and M the/ bulk of 

 the refidual air; M — 6-|-c=n, or refidual nitrogen, and 

 a — n^=.x or nitrogen abforbed. 

 Experiment I. June 16, 1803. 

 600 c. inches of atmofpherical air were refpired, for four Exp. 1,2, 3. 

 minutes, at the temperature of 63*^. , The bulk of 



' nitrogen abloibed 



* De Marti is of opinion that the hidrogenated fulphurets ab- in refpira'i m 

 foib nitrogen only when recently formed. Vide Journal de Phyfique. was about i-,4ofli 

 T- TTTT 1%-^ of the whole, or 



tjf^om. LIII. p. 176, 



Before 



