346 Scientific Proceedings, Royal Dublin Society. 



other constituents forming the fixed matter call for little or no 

 comment with the exception of the phosphoric acid, which for a 

 highly adulterated guano is much above the average ; the mag- 

 nesium oxide and nitrates, both of which were present only in 

 very small quantity, were not directly estimated, the amount 

 being determined by difference. A remarkable feature in this 

 guano is the nitrogen, which, besides being naturally low, is en- 

 tirely present in the form of ammoniacal salts : the minute amount 

 of organic nitrogen, *02 per cent., shown in the analysis, is no 

 doubt due to partial conversion of the nitrogen of nitrates into 

 ammonia during the ignition with soda-lime in presence of the 

 organic matter. 



In order to give a better idea of the extensive adulteration of 

 the sample, I append below the calculated composition of a ton o£ 

 the original guano. 



Composition of a Ton of Okiginal Guano. 



cwt. lbs. 



Sand, stones, &c. (adulteration), . . . 7 89 



CaO, 1 96 



P2O5, 2 35 



S0 3 , 37 



K 2 0, 89 



MgO and nitrates, 32 



Water, 2 18 



Organic matter, ...... 3 57 



Total nitrogen, 72 



19 77 



The deficiency here is due to the fact that the calculation is not 

 carried beyond pounds, and the ammonia in the guano is calcu- 

 lated to nitrogen only. The extensive adulteration in the above 

 case is probably the work of the exporters of the guano; never- 

 theless the Dublin merchants who supplied it are not without 

 blame, on account of either ignorance or carelessness in the selec- 

 tion and examination of their own purchase. 



