23 



The following analyses show the proportions of phosphoric acid 

 and nitrogen in each of these types of guano: 



Sand and silica. Moisture. Phos. acid. Nitrogen. Aram. 



1st Class 11.24 24.60 3.20 3.88 



2nd " .80 18.00 14.80 13.50 16.40 



3rd " 19.80 12.50 9.18 8.40 10.20 



Physical properties. While the guano is often mixed with small 

 stones, pebbles, sand, and material containing phosphates, a good pro- 

 portion of it is very finely divided and only needs sifting to make it 

 ready for the field. Some of the guano reaches the estate in the crude 

 form containing large lumps which are nothing but caked manures 

 easily disintegrated, and if leached with water give a straw colored 

 solution containing a good amount of nitrogen and phosphoric acid. 

 A guano like this needs but little mechanical treatment to give it the 

 physical condition of a chemical fertilizer. 



Chemical conditions. This guano is equally interesting chemically. 

 Some of the phosphoric acid is immediately available and is soluble 

 in water; other portions are soluble in the "Citric Solution". Still 

 more interesting is the character of the nitrogen, some of which is in 

 the form of free ammonia. In some of the guanos the total water- 

 soluble nitrogen amounts to 2.5$. Potash is present in small propor- 

 tions, .5 to 1.%. 



The following analyses show the composition of some of the Peru- 

 vian guanos: 



Island "Lobos de Afuera" (chiefly for export). 



Volatile Sand Phos. Acid. Nitrogen. 



Matter % % % % 



23.11 4.00 32.57 1.47 



27.53 23.03 20.22 3.14 



From Other Islands. 



