15 



oxygen gas lost, which the experiments both of 

 Cruickshank and Saussure forbid us to believe, and 

 which, in all our own experiments, appeared to be 

 somewhat less. 



13. If, then, we may be permitted to suppose, 

 that in the process of germination the oxygen gas 

 of the air loses about 1-1 Oth of its bulk by passing 

 into carbonic acid, it follows, that the 3.78 cubic 

 inches of this acid, which appeared to be attracted 

 in the foregoing experiment, (10.), will actually 

 consist only of 3.4O2 cubic inches. Now, one cu- 

 bic inch of carbonic acid weighs 0.467 of a grain, 

 and therefore 3.402 cubic inches will weigh 1.589 

 grains, which may be taken as the weight of the 

 carbonic acid actually produced. But farther, a cu- 

 bic inch of oxygen gas weighs O.3474 of a grain; 

 and therefore 3.62 cubic inches (the bulk of that 

 gas present in the experiment) will weigh 1.261 

 grains, which is less by 0.328 of a grain than the 

 weight of the carbonic acid produced. This greater 

 weight of the acid, therefore, must be attributed to 

 the carbon which united with the oxygen gas to 

 form it, and which makes the carbon to constitute 

 of the compound. According to Lavoisier, car- 

 bonic acid contains -^ zz ~~ of carbon ; and ac- 

 cording to Dr Priestley, the weight of the carbon is 

 about l-4th of the compound* : but Guyton, who 

 formed this acid directly by the combustion of dia- 

 mond, found that one part of diamond combined 



Experiments on &ir Abridged, vol. iii. p. 37' 



