1 28 Memoir upon Guano. 



Its solubility in water, and, above all, in potash, deter- 

 mined the method to be taken in its analysis. They sue-* 

 cessive.ly tried it by means of water, potash, and muriatic 

 acid : each of thcs;^ trials jrave occasion to observe several 

 phasnomena, of which we shall give a succinct account 

 without entering into the details, which may be too exten- 

 sive for an extract. 



Ten grammes of this substance, repeatedly washed in great 

 quantities of boiling water, were reduced to 5*7 grammes. 

 The lev had a reddish colour, and reddened turnsole paper. 



Submitted to distillation in B. M., it furnished ammonia 

 during the whole operation : 24 hours afterwards it depo- 

 sited a reddish yellow powder, a little sapid, having the 

 odour of castv)r; and it presented on its surface a crystalline 

 pellicle of the same colour as the' precipitate. 



The liquor, filtered and evaporated a second time until it 

 was reduced to 3 grammes, still deposited, on cooling, a red- 

 dish yellow powder, like the first, but less abundant. 



The yellow powder and the mother water which held it 

 in solution were examined separately. 



The former presented the following properties: — It is a 

 concrete and pulverulent substance, of a brilliant and crystal- 

 line appearance, and of a reddish yellow colour. Exposed to 

 heat, it burns entirely, and gives out a slight empyreumatic 

 odour of ammonia and prussic acid. Although little soluble 

 in cold water, it is easily so in warm, to which it comnnmi- 

 cati's a yellowish colour ; and, although the solution is taste- 

 less, it reddens the tincture of turnsole; it precipitates the 

 solutions of acetate of lead and of nitrates of silver and mer- 

 cury in coloured Hakes, which the nitric acid redissolves 

 completely. 



This substance dissolves instantly in an alkaline ley, to 

 which it communicat*§. a brown colour, exhaling a lively 

 odour of ammonia. Sulphuric acid, mixed with a concen- 

 trated alkaliiic solution, yields a vciy thick whitish precipi- 

 tate, and liberates a sharp smell similar to that of weak acetic 

 acid. 



The celebrated authors of the memoir concluded from 

 these experiments that this powder presents itself as an aci- 

 dulated 



