NEITHER POTASH NOR, AMMONIA. 



the light it becomes first green, and afterwards 

 brown, without any other apparent alteration. I 

 have not myself made any experiments on this 

 salt ; but from the analysis of it by Mr. Vogel, 

 there can be no doubt that it is composed of 



1 atom oxalate of soda 8-5 



1 atom oxalate of copper 9'5 



2 atoms water 2-25 



20-25 



8. Carbono-phosphate of soda. There is a 

 prussian blue manufactory in the neighbourhood 

 of Glasgow belonging to Mr. Macintosh, in 

 which, likewise, prussiate of potash is made in 

 very considerable quantities. The acid is ob- 

 tained by the combustion of the hoofs of black 

 cattle, imported chiefly from Ireland; and the 

 hoofs of a thousand cattle are required for every 

 day's consumption in the manufactory. The 

 slaughtering of cattle in Ireland having considera- 

 bly diminished at the end of the last war, hoofs 

 became scarce. This induced Mr. Macintosh 

 to substitute the animal substance called crack- 

 nales, procured chiefly, I believe, from the 

 candle makers. Soon after this substitution, 

 considerable quantities of a white salt in fine 

 needles began to make their appearance in the 

 prussiate of potash leys, and incommoded the 

 process considerably. These crystals exhibiting 

 appearances different from any of the common 



F f 2 



