4ft Materials for a History of the P r us slates. 



of charcoal, and the same quantity of carbonate. The lix- 

 ivium hem? finished, the charcoal extracted was only 104 

 grains : 40 grains were destroyed. 



Thc.'e 104 grains were again treated with 144 of carbonate: 

 they were reduced to 62 ; loss 42. 



The lixivium of these two experiments was saturated with 

 the solution of the sulphate of iron used in commerce : the 

 blue of the first, after the colour was struck, was double in 

 volume to that of the second. 



In order to ascertain the influence of temperature, I tried 

 three mixtures of equal quantities. The first was kept red- 

 hot for half an hour, the second one hour, and the third an 

 hour and a quarter. The first lixivium gave very little blue; 

 the two last gave a great deal, and much about the same 

 quantity. These results prove either that the simple prus- 

 siate, being that which predominates in the lixiviums, is 

 preserved in the midst of the carbonaceous alkaline mass, or 

 that it is reproduced in proportion as it is destroyed. 



Tue charcoal of blood, pulverized, liquefies in the air : 

 when washed, it gives sea salt, and carbonate of soda hold- 

 ing a little prussic acid in solution. 



The charcoal of blood, when treated in this way a second 

 time, still yields blue, but in small quantity ; a third, less 

 sensibly; a fourth, not at all. This charcoal, when made 

 red-hot, is incinerated with much facility without exhaling 

 the ammoniacal smell. It appears, that in proportion as it 

 loses the azote, it becomes more combustible, and resem- 

 bles more closely vegetable charcoals : the nitric acid, how- 

 ever, does not inflame it. The azote being susceptible of 

 forming concrete combinations capable of resisting a high 

 temperature, what would be the influence of animal char- 

 coal in the formation of steel ? 



Equal parts of charcoal of blood, washed, and of pot- 

 ash rendered caustic by lime, yielded, by the distillation of 

 the simple prussiate of ammonia, plenty of gas, which had 

 the same smell with the prussic, and which burns red. 

 - Equal parts of this same charcoal, and of oxide of manga- 

 nese, yielded carbonate and prussiate of ammonia. 

 ■ The desire of forming ammonia to some profit, led me to 



the 



