on the Specific Weight of Chemical Cumpuunds. 181 



For the carbonates the following rule may be given. To 

 the primitive atomic volumes of the heavy metals, or the pe- 

 culiar ones of the light metals, the number 151 must be added, 

 which is the assumed atomic volume of C O^. In this manner 

 the following atomic volumes and densities of the carbonates 

 are obtained: — 



PI) + COS . 

 Cd + CO'. 

 Fe + C 03 . 

 Mn + CO'.. 

 Ag + CCF . 

 Zn + C 03 . 



Atom. Calcu. Obser. 

 Vol. Sp.Gr. Sp.Gr, 



2Go 

 2.32 

 195 

 195 



281 

 209 



6-30 

 4-63 

 3-67 

 3-70 

 615 

 3-73 



6-43 

 4 49 

 3-83 

 3-59 

 608 

 4-44 



Salts. 



BaC03 

 Ca C 03 

 KCO«.. 

 MgC03 

 NaC03 

 SrC03 



Atom. CalciLlObser. 

 Vol. Sp.Gr.lSp.Gr. 



294 

 211 

 385 

 191 

 281 

 259 



4-19 

 300 

 2-25 



2-80 

 2-37 

 3-56 



4-24 

 300 

 2-26 

 2-98 

 2-47 

 3-60 



And for the double salts, 



Bitterspar / q^q^ \ i02 - 2-90 - 2-88 



Mesitin ^p/(f(^^ \ 386 - 3-24. - 3-35. ' 

 All these agree very well, except the zinc salt. 



In the nitrates the atomic volume of N" O*' is assumed to 

 be = 358. 



In several of the sulphates the atomic volume of SO'' may 

 be assumed to be 236. According to this the following salts 

 were calculated : — 



But the assumption of 236 as the atomic volume of S O** 

 tloes not hold good in some of the other sulphates, so that we 

 are obliged to assume that there are two groups of sulphates, 

 in one of which S O' has the atomic volume 236, and in the 

 other 186. According to this latter number the following 

 salts have been calculated : — 



