JJ14 M. Dumas on the Equivalents. 



19 



Fluorine. 



19 + 16-5 = 35-5 .... Chlorine. 

 19 + 33 + 28 = 80. . . . Bromine. 

 38 + 33 + 56 = 127 . . . Iodine. 



For nitrogen, phosphorus^ arsenic, antimony, and bismuth, we 

 should have the formulae — 

 a 



a + d 

 a + d+d' 

 a + d+2d' 

 a + d+4!d'; 

 or in numbers, 



14 Nitrogen. 



14+17 = 31 Phosphorus. 



14 + 17 + 44 = 75 . . . Arsenic. 

 14+17 + 88 = 119. . . Antimony. 

 14 + 17+176 = 207 . = Bismuth. 

 Carbon has the equivalent 6. Deville has recently deter- 

 mined that of boron by the analysis of chloride and bromide of 

 boron, and has found it to be 11. The equivalent of silicon 

 deduced from analyses of the chloride gave Dumas numbers 

 between 21 and 21 "2, which represent, however, a maximum, as 

 the chloride, notwithstanding the greatest care taken in its pre- 

 paration, always contained phosgene gas in solution. The num- 

 ber 21 may be taken as the right one. The equivalent of zir- 

 conium is 33. The numbers 6, 11, 21, 33 are expressed by the 

 formula — 



a 



a + d 



a-\-Sd 



3a + 3d 



6 Carbon. 



6 + 5 = 11 .... Boron. 



6 + 15 = 21 .... Silicon. 



18+15 = 33 . . . Zirconium. 



Oxygen, sulphur, selenium, and tellurium form another series, 

 which may be represented either by the general formula — 



The analogy of other groups would lead to the adoption of the 

 latter. 



k 



