129 



timates at 32 cubic inches, being composed of nitrogen 

 23, carbonic acid 4.1, and oxygen gas 4.9 *. When 

 he breathed the nitrous oxide, the proportions of these 

 residual gases appeared nearly the same as when hy- 

 drogen gas was respired ; which led him to conclude, 

 that no portion of the nitrogenous or oxygenous 

 gases was produced by the decomposition of the oxide 

 in the lungs t But a reference to the results of Mr 

 Davy's experiments will shew, that the carbonic acid 

 in the lungs and air-holder, which, before breathing 

 the oxide, was estimated at 4. 1 , was afterwards increa- 

 sed to 5.2 cubic inches ; and that the oxygen gas also 

 was increased from 5.6 to 6. 1 . In another experiment, 

 the carbonic acid was increased, after breathing the 

 oxide, from 4.1 to 6.8, and the oxygen gas, at the 

 same time, from 5.5 to 6.3 ; and Mr Davy admits, 

 " that the quantity of carbonic acid and oxygen is ra- 

 ther greater than that which existed in the experi- 

 ments on hydrogen J." Finding, indeed, the bulk of 

 these two gases in the lun s and air-holder to be on- 

 ly 9 cubic inches when hydrogen was respired, and 

 that it amounted to 13.1 when nitrous oxide was 

 breathed, and, denying that the acid is formed by 

 the immediate decomposition of the nitrous oxide it- 

 self, Mr Davy is led to believe, that " it is wholly 

 or partially liberated from the venal blood through 

 the moist coats of the vessels ;" a supposition, a- 

 gainst which it has, we trust, been already suffi- 

 ciently argued. 



* Researches, p. 409. f Ibid. p. 41 4-. 



t Ibid. p. 413. 415. Ibid. p. 420. 422. 



I 



