4 On the transmission 



Experiments made 'x'lth Charcoal, Phofphorus and Animal 

 Fibres in the Nitrous Acid. 



I have formerly given an account of experiments 

 on the lolution of charcoal in the nitrous acid ; and as 

 there is fome diverfity in 'the refults, it may be of ufe to 

 add the fo]Iov\dng : 



Some pieces of pounded charcoal diflblvcd with difficul- 

 ty in nitrous acid, but with heat it conftantly gave air, 

 of which about one-fifth was at firft fixed air, and the reft 

 nitrous; but at laft it was wholly phlogifticated. At 

 another time half of the produce was fixed air, and tlie 

 reft phlogifticated. 



From 205 grains of perfect charcoal and three ounce 

 meafures of ftrong acid of nitre, I got 180 ounce mea- 

 fures of air, of which at firft only onc-fixth, but at laft 

 one half, was nitrous, and the reft fixed air. With frefh 

 acid to the remainder of the fame charcoal I got 82 

 ounce meafures of air, of which at firft only one-fixth 

 was nitrous, with equal meafures of common air occupy- 

 ing the fpace of 1.6. Of the reft one half was more 

 purely nitrous. The phial in which the folution was 

 made becoming dry, and prefently after red hot, I got 

 with great rapidity, and in a very turbid ftate, 50 ounce 

 meafures more ; and of this one half was fixed, and the 

 remainder phlogifticated. 



Charcoal of copper appeared to differ from that of 

 wood in that, being diffolved in the nitrous acid, it gave 

 only nitrous air, without any fixed air, and very little 

 phlogifticated air. From this it may be inferred that 

 charcoal of copper contains no oxygen, which charcoal 

 of wood does, and by which it can give fixed air. 



The different refults of diffolving copper, phofphorus, 

 and animal fibres in the fame quantity of the acid of nitre 

 may give rife to fome ufeful obfervations. 



Having 



