SALTS 



which are not altered by exposure to the air. 

 They are composed of 



1 atom acetic acid . . 6-25 



1 atom protoxide of manganese 4-5 

 4 atoms water . . . 4-5 



15-25 



Protoxa- 8. Protoxalate of manganese. This salt may 

 be formed by mixing rather concentrated solu- 

 tions of oxalate of potash and sulphate of man- 

 ganese. No immediate precipitation ensues ; 

 but after some time the mixture becomes muddy 

 and the salt subsides. It is a very soft tasteless 

 powder, having a white colour, with a very slight 

 shade of pink ; it is insoluble in water, and pro- 

 duces no change on vegetable blues ; when mo- 

 derately heated it gives out abundance of water. 

 Being analyzed by driving off the water on the 

 sand bath, and then calcining it in a strong red 

 heat, its constituents were found to be 



1 atom oxalic acid . . 4-5 



1 atom protoxide of manganese 4-5 

 3 atoms water . . . 3-375 



12-375 



9. Tartrate of manganese. This is a beauti- 

 ful transparent salt, having rather a deep brown- 

 ish red colour ; the crystals are four-sided prisms, 

 exceedingly little soluble in water. This salt has 



