254 . On the Changes produced in Atmospheric Air 



wards in the eudiometer with the tests for oxygen ; and there 

 were still exactly 40 parts Jeft ; proving that the hyperox- 

 ygenized muriatic acid gas has no action upon azote. 



We then examined the bottles containing the residuum 

 from the air that had been so often respired, and found that 

 it had not experienced the slightest change; it was therefore 

 plainly azote ; and on reflection, it occurred to us, that if a 

 certain proportion of oxygen had been absorbed or lost in any 

 way, while the azote remained unaltered^ there must be an 

 increased proportion of the latter. 



Now we knew exactly both the bulk and the constitution 

 of the air before the experiment ; but it was impossible to 

 know the bulk or volume after the experiment otherwise than 

 by calculation. 



The 300 cubic inches of atmospheric air before the ex- 

 periment contained 21 oxygen, 79 azote in 100 parts, making 

 the total quantity of oxygen 63 cubic inches, 

 azote 237 



500 



Now if the lungs be capable of fixing permanently any 

 azote from the atmosphere, it appears by our experiments 

 that the quantity must be very minute, seeing that, in the 

 ] 1th, 12th, and 13th experiment, it did not disturb the pro- 

 portion of azote, as shown by the eudiometer ; we shall there- 

 fore in the present instance assume the volume of azote after 

 the experiment at 237 cubic inches, as before. 



But after the experiment, every 100 parts consisted of 86 

 parts azote, and 14 oxygen, either in the form of carbonic 

 acid, or free. 



S6 : 14 : : £37 : 38-38. 

 Therefore the total quantity of oxygen left after the experi- 

 ment would have been 38*58 cubic inches. 



Then 237 azote -f- 38-58 oxygen = 275*58; 

 the quantity of gas after respiration would therefore have 

 been 275*58 cubic inches. 



300 — 275*58 = the loss of oxygen, or 24*42 cubic inches. 

 It appears, therefore, that 24*42 cubic inches of oxygen had 



been 



