SPECIFIC GRAVITY OF PIYDROGEN GAS. 73 



Biot and Arago's is too high by rath part, Ber- 

 zelius and Dulong's too low by rfjth part, 

 while my results, owing probably to a fortunate 

 accident, are, as far as they go, quite correct. 

 Water being; a compound of 1 volume of oxy- C 



. . f tion of wa- 



gen gas, and 2 volumes ot hydrogen gas, it is ob- ter. 

 vious, that it is composed of 8 parts, by weight, 

 of oxygen, and 1 part of hydrogen. There can 

 be no doubt that water is a neutral compound, 

 and that it consists of an atom of oxygen united 

 to a determinate atomic quantity of hydrogen ; 

 but chemists are not yet quite agreed whether 

 the hydrogen be 1 atom or 2 atoms. Sir H. 

 Davy and Professor Berzelius consider the hy- 

 drogen as amounting to two atoms, because there 

 are 2 volumes of it united to 1 volume of oxy- 

 gen ; for they consider the volumes of these 

 gaseous bodies as representing atoms. On the 

 other hand, Mr. Dalton, Dr. Wollaston, Dr. 

 Prout, and indeed by far the greater number of 

 chemists, consider water as a compound of 1 

 atom oxygen, and 1 atom hydrogen, founding 

 their opinion upon the well known fact, that these 

 two gases cannot be directly united in any other 

 proportions than those which exist in water. 



If water contain only 1 atom of hydrogen, the 

 atomic weight of this substance is obviously 

 ath of that of oxygen, or 0-125 ; but if that 

 liquid contain 2 atoms of hydrogen, then the 

 atomic weight of hydrogen is only 0-0625. 



