74 



PROCEEDINGS OF THE AMERICAN ACADEMY 



ists have not been systematized. The very numerous vanadates may 

 be arranged, as I find, under seven groups or series. These are here 

 given for the sake of compai'ison, typical salts actually obtained in 

 each series being marked by the initials of the analysts. The exist- 

 ence of salts corresponding to other general formulai is a matter of 

 inference only. As will be seen at once, the first series corresponds 

 to the group of metatungstates, if we compare V2O2 . 0, with WO3. 

 Terms 1 and 3 of this series of vanadates have twice the usually 

 given molecular weights. 



First Series. 



Vanadates. 



KJO . 4 V0O5 



E. 2 K,,0 . 6 V2O5 2 R2O 



N. 3 Na.O . 8 V2O5 + 24 aq 3 RoO 



R. 4NaoO. 10 VgOj-f 14aq 4 R^O . 



5 R.,0 . 12 V.A 5 RoO 



Metatungstates. 



KjO . 4 WO3 



6 WO3 



8 WO3 



10 WO3 



12 WO, 



N. 

 R. 

 R. 



Second Series. 



Na^O 



2 K06 



3 LioO 



4 R,0 



3VA 

 5 VA 

 7 VA 



Third Series. 



R. K.O . 2 V2O. + 4 aq 

 R. 3 Li20.4 VA+ 12aq 

 R. 5 LiaO . 6 V2O5 + 30 aq 



7R«0 



8 V2O, 



Fourth Series. 



R. 3 Li20.2 VA + 15aq 



4 RoO . 4 V2O5 



5 R2O . 6 VgO^ 



6 R2O .8 V A 



R. 



Fifth Series. 



2 K2O 

 3R2O 

 4R2O 

 5 R2O 



V.O, 4- 3 aq 

 3 V2O. > 

 5VA 

 7VA 



Sixth Series. 



4 R2O . 2 V2O5 



R. 5 KoO . 4 V2O5 + 7 aq 



6 R2O . 6 V2O. 



7 RoO . 8 V2O, 



Seventh Series. 



Ro. 3 Xa.O . V2O5+ 16 aq 



4 RoO . 3 V2O5 



5 R2O . 5 V2O5 



6 RoO . 7 VoO, 



The seven series which I have given embrace, I believe, all known 

 types of vanadates. Each series may be represented by a general 

 formula expressing the relation between the number of molecules of 

 acid and basic oxides. These general formulae are : 



