606 AGRICULTURAL ANALYSIS 



In a sample examined at the Connecticut station the percentages 

 of its chief constituents were found to be the following: 81 



Water 51.84 



Organic and volatile matters 24.27 



Ash 23.89 



The organic matter contained 0.6 1 per cent, of nitrogen as am- 

 monia and the ash 0.97 per cent, of phosphoric acid, and 0.59 per 

 cent, of potash, all calculated to the original weight of the sam- 

 ple. The percentage of water in this sample is undoubtedly 

 higher than the average, so that it can hardly be taken to rep- 

 resent the true composition of this manure. The potash, phos- 

 phoric acid, and nitrogen are to be determined by some one of 

 the standard methods already described, the two former after 

 careful incineration. 



513. Guanos and Cave Deposits. The principal constituents 

 of value in these deposits are nitrogen and phosphoric acid. The 

 other organic matters are also of some value, but have no com- 

 mercial rating. The nitrogen may be present in all its forms ; 

 viz., organic, ammoniacal, amid, and nitric, and for this reason 

 is well suited not only to supply nourishment to the plant in the 

 earlier stages of its growth, but also to cater to its later wants. 

 In guano deposits in caves, due usually to the presence of bats, 

 similar forms of fertilizers are found and the soluble constituents 

 due to decay and nitrification are protected from the leaching to 

 which they would be subjected in the open air. 



In some localities in the United States a few open deposits are 

 found, but the humidity of our climate, except in the arid regions 

 of the West, has prevented the immense open deposits of guano 

 that characterize some of the arid islands of the Pacific Ocean. 



Many bat guanos examined in the laboratory of the Bureau 

 of Chemistry have been found to contain potash, in one case 

 1.78 per cent. It is suggested, therefore, that the analyst do 

 not omit to examine each sample qualitatively for this substance 

 and to determine its amount when indications point to its pres- 

 ence in weighable proportions. In the many samples of bat 

 guano of American origin which have been analyzed in the last 



81 Connecticut Agricultural Experiment Station, Annual Report, 1888, :: 

 80. 



