GUANO. 20 1 



ammoniacal salts in abundance, but also those inor- 

 ganic constituents which are indispensable for the 

 development of plants. 



The most recent analysis is that of Volckel, who 

 found it to cons'ist of 



Urate of Ammonia .... 9*0 



Oxalate of Ammonia . , . 10-6 



Oxalate of Lime .... 7-0 



Phosphate of Ammonia . . . 6*0 



Phosphate of Magnesia and Ammonia . 2'6 



Sulphate of Potash .... 5*5 



Sulphate of Soda . . . . 3'8 



Sal-ammoniac ..... 4*2 



Phosphate of Lime .... 14-3 



Clay and sand ..... 4-7 

 Organic substances not estimated, con-^ 



taining 12 per cent, of matter insolu- |^ nn.o 



ble in water. Soluble Salts of Iron f 



in small quantity. Water . . J 



100.0 



It will be observed from the above analysis, that 

 urea does not enter into the composition of guano. 

 The uric acid of the excrements must have been 

 decomposed into oxalic acid and ammonia. The 

 soluble substances contained in guano amount to 

 half its weight. It is singular that we do not find 

 nitrates amongst the ingredients which compose it. 

 Guano possesses a urinous smell, precisely similar 

 to that perceived on the evaporation of urine. The 

 » experiments upon the efficacy of this manure in 

 England have not yet been suflRciently multiplied to 

 enable us to judge whether or not its virtues have 

 been overrated. 



The corn-fields in China receive no other manure 

 than human excrements. But we cover our fields 

 every year with the seeds of weeds, which from 

 their nature and form pass undigested along with 

 the excrements through animals, without being de- 

 prived of their power of germination, and yet it is 

 considered surprising that where they have once 

 flourished, they cannot again be expelled by all our 

 endeavors : we think it very astonishing, while we 

 really sow them ourselves every year. A famous 



