154 



gas employed, but this variation does not destroy 

 our belief in the general fact : and if we consider 

 that these calculations have been formed from expe- 

 riments where the authors had no such circumstance 

 in their contemplation ; that the correct observation 

 of the fact itself requires an attention to many cir- 

 cumstances of much delicacy and difficulty ; and 

 that the composition of carbonic acid is not yet de- 

 termined with such rigour as to leave no room for 

 doubt, we must be satisfied with such an approxi- 

 mation towards the truth, as our present knowledge 

 entitles us to make. In conformity, therefore, with 

 these views, we venture to conclude, that oxygen 

 gas, by its conversion into carbonic acid, suffers in 

 respiration, as well as in combustion, a diminution 

 of about one-seventh of its bulk : and since this ne- 

 cessary diminution accounts nearly (122.) for the 

 whole difference in volume between the oxygen gas 

 lost, and the carbonic acid produced in respiration, 

 we may farther conclude, that the whole of this oxy- 

 gen ga 3 has been employed to form the carbonic acid 

 in question. 



1 24. But, notwithstanding this diminution of vo- 

 lume, which the oxygen gas thus experiences by 

 uniting with carbon, the weight of the compound 

 that is formed, is, at the same time, increased. 

 MM. Lavoisier and Seguin estimated the weight of 

 oxygen gas, consumed by a man in 24 hours, at 

 15661.66 grains: and that of carbonic acid produ- 

 ced in the same space of time, at 17720.89 grains * : 



Bostock on Respiration, p. 83. 8G- 



