9 



that of his laboratory was found to do), the 11.5 

 cubic inches of it which he used in this experiment, 

 will, he says, consist, before the introduction of the 

 peas, of 3.105 of oxygen, and 8.395 of nitrogen : 

 and at the close of the experiment he states the com- 

 position of the air at 1.88 oxygen, 8.395 nitrogen, 

 and 1.035 carbonic acid ; consequently 1.255 of 

 oxygen were employed to form 1.035 cubic inches 

 of carbonic acid, a result as near to truth as can be 

 expected in observations on small volumes of air. 

 In other experiments made over water, nearly the 

 same results are said to have been obtained *. But 

 some error seems to have crept into the calculations 

 of M. de Saussure ; for, if with him we consider 

 the atmosphere as containing ^ of oxygen gas a 

 11.5 cubic inches of air will contain 2.415 of oxy- 

 gen, and 9.085 of nitrogen ; proportions very dif- 

 ferent from those which he has assigned, and which 

 necessarily affect all the subsequent calculations, and 

 the conclusions he has drawn from them. 



8. With the view, therefore, of ascertaining this 

 point with more precision, we placed one dozen of 

 peas, which had been steeped in water thirty-six 

 hours, and whose surfaces were dried afterwards by 

 blotting paper, on a small whalebone hoop covered 

 with gauze, which was pushed half way up into a 

 glass-jar well dried, and of the capacity of 18.2 cu- 

 bic inches. This jar, filled with atmospheric air, 

 was then inverted into a deep saucer, where it stood 

 over a small glass-cup, containing half a cubic inch 



Journal de Physique, torn, xlix. p. 92. 



