120 Review of Dr. Thomson 



5. Hydrogen with azote, or ammonia. This compound con- 

 sists of 1 azote =14 + 3 hydrogen =s 3, whose joint weight is 

 7 ; and as these 4 volumes compose 2 of ammonia, the resulting 

 specific gravity will be y = 8j times that of hydrogen. The 

 specific gravity becomes here one-half of the atomic weight. 



6. Hydrogen with azote and carbon ; the prussic, or hydro- 

 cyanic acid. This body consists of 2 carbon = 12, + 1 azote = 

 14, + 1 hydrogen = 1, whose sum is 27; which 4 volumes 

 together constitute 2 ; therefore the specific gravity is %f = 131 

 times that of hydrogen ; while the atom is the double. 



7. Cyanogen, or bicarburet of azote. It consists of 2 carbon 

 = 12, +1 azote =14, whose sum is 26; and as these 3 vo- 

 lumes form 1, its specific gravity will be 26 times that of hy- 

 drogen. 



8. Sulphuretted hydrogen. This is composed of 1 sulphur = 

 16, + 1 hydrogen = 1, whose sum = 17, is the specific gravity 

 of the gas compared to hydrogen, for the hydrogen does not 

 change its volume in combining with the sulphur ; or a volume 

 of hydrogen gas and one of vapour of sulphur compose one volume 

 of sulphuretted hydrogen gas. 



When oxygen is contemplated in the general relations of 

 weight and volume to hydrogen, we must bear in mind the 

 hypothetical assumption at the root of both schemes of equivalent 

 numbers ; viz., that half a volume of oxygen = 8 is the primi- 

 tive combining proportion. If we regard water as consisting of 

 2 volumes of hydrogen + 1 of oxygen, the entire volume of 

 oxygen becomes 16, and therefore we shall have 2 + 16 = 18 

 for the total weights ; and as these 3 volumes of constituents 

 form 2 volumes of aqueous vapour at 212° Fahr., we shall have 

 its density L8 = g ? an( j if hydrogen be called 0.0694 in reference 

 to air = 1, the vapour will become 0.625 = 9 X 0.06944. 

 As the density is here compared to air of the same temperature, 

 the relation of 0.625 to 1 will continue through the thermometric 

 range, since vapours out of contact of their liquids, and gases, 

 suffer the same change of volume by change of temperature. 

 The diminished specific gravity of the vapour will be therefore 

 simply proportional to its diminished tension or elastic force. 



The preceding exemplification of the value of the hydrogen 

 radix, will we trust satisfy our readers, that Dr. Thomson must 

 have formed a somewhat crude conception of chemical equiva- 

 lents, when he talks so slightingly of that atomic scale. He 

 should reserve his dogmatic decisions for more tangible matters. 

 In a word, let any practical man compare the hydrogen and 

 oxygen scales in reference to the water of crystallization of salts, 

 and he will readily find that 9 and its multiples, are much more 

 manageable than the multiples of 1.125. 



But the Doctor is not content with reasoning alone ; he must 

 needs exemplify, and his manganese case is a droll enough proof 



