ABSORPTION OF NITROGE^M. 4^ 



ever, when the air in the gafometer became vitiated, and the 

 refpirations fuller and quicker, fome difagreeable effefts were 

 experienced from the fmallnefs of the breathing tube, and 

 from it becoming, in fome meafure, choaked by the vapor 

 from the lungs, which was condenfed in it. 



After clofing the noftrils, and making a forced exhauftion Method of rc- 

 of the air in the lungs, a full infpiralion was made of the '?"■'"»' 

 atmofpherical air in the gafometer, and this infpiralion as well 

 as the fubfequent expiration, was meafured, by means of ilie 

 graduated fcale. The air of the gafometer was then refpired 

 as long as poffible, and till the oppreffion about the cheft be- 

 came fo great as to oblige theexperimenter to defift, and before 

 clofing the ftopcock, and feparating the tube from the mouth, 

 the magnitude of the lafl: full infpiration and expiration was 

 accurately obferved. 



In all our experiments, the bulk of the atmofpherical air and general 

 was confiderably diminiHied by refpiration, the quantity that ^^'^'^^"°^^'^* 

 difappeared varying from five to eight c. inches per minute. 

 This diminution, however, is partly to be attributed to the 

 condenfation of the oxigen gas, when converted into carbonic 

 acid gas, in which form its bulk is diminifhed about one fourth. 

 In order to obviate any objeflions that might apparently arife 

 from the difference of the infpirations and expirations at the 

 commencement, and at the conclufion of the experiments, 

 they were, as we have already mentioned, carefully noted ; 

 and if any difference did occur, it was dedudted on the lide 

 where the preponderance took place. 



In proceeding to examine the chemical qualities of the air, Eudiometncat 

 confiderable difficulties were at firfl experienced for want of '^^^'"'"^'*°"* 

 an accurate eudiometer. Several trials were made with 

 nitrous gas, which affords the mofl cafj and expeditious mode Nitrous gas 

 of analyfing atmofpherical air. But, independent of the in- exceptionable. 

 accuracies which may arife from the number of vedels it is 

 neceffary to have recourfe to in employing it, this tefi is 

 liable to flill greater objedions, from differences in its degree 

 of purity, from its abforbing a portion of nitrogen, and from 

 its combining with a greater or lefs proportion of oxigen, ac- 

 cording to the diameter of the veffels employed, the length of 

 time which it is allowed to remain in contad with atmof- 

 pherical air, and the degree of agitation ufed in mixing 

 them. 



The 



