122 Farmyard Manure. 



A year or two acfo Mr, Barral], a French chemist, published 

 some experiments, which purpose to prove the power of salt to 

 fix ammonia in Peruvian guano, and to account thereby for the 

 benefit which results from the mixing of guano with salt. I 

 have carefully repeated Mr. Ban-all's experiments, and shall 

 publish the details of my analytical results shortly elsewhere ; 

 but, fearing I might be considered dogmatic in distinctly stating 

 that salt is incapable of fixing free ammonia in guano, I beg to 

 observe that 1 have been led to this conclusion by a series of 

 experiments which are opposed in their results to Mr. Barrall's. 



For the purpose of giving an idea of the actual quantity of free 

 ammonia (carb. of ammonia) in Peruvian guano, I would mention 

 in this place the following experiment : — A quantity of Peruvian 

 guano, which on analysis gave the subjoined analytical results, 

 was mixed with a little water, and distilled in a retort to dryness 

 at a temperature not exceeding 212° F,, and the distillate care- 

 fully collected in hydrochloric acid. On evaporation of the 

 acid liquor in the receiver, sal ammoniac was obtained, from the 

 weight of which that of ammonia volatilised with the watery 

 vapours produced on distillation was calculated. 



The following is the result of this determination. 100 parts 

 of genuine Peruvian guano were found to yield '573 of am- 

 monia : — 



Composition of Peruvian Guano used in this Experiment. 



Moisture 12-78 



* Organic matter and aramoniacal snlts .. .. 53-08 

 Phosphates of lime and magnesia (hone-earth) 24-50 



Alkaline salts '" 8-99 



Insoluble silicious matter (sand) -65 



100-00 



* Containing nitrogen 13-18 



Equal to ammonia 15'96 



The same guano distilled with an excess of quicklime and 

 some water, with a view of liberating the ammonia which existed 

 in this sample of Peruvian guano in the form of ammoniacal 

 salts, produced 6'931 of ammonia. Though we are in the habit 

 of speaking of guano as an ammoniacal manure, it appears from 

 these determinations that the smaller proportion of nitrogen is 

 contained in Peruvian guano as ready-formed ammonia, and the 

 larger proportion as uric acid, urea, and other nitrogenised com- 

 pounds, which, however, in contact with water, are readily 

 decomposed and yield ammonia. 



The quantity of free ammonia and ammonia in the form of 

 ammoniacal salts, of course, is not constant in different samples : 

 I may state, however, that in dry genuine Peruvian guano I 



