210 



Composition and Value of Guano. 



The lowest per centage in the table is 

 The highest „ „ 



The average of 11 specimens being . 

 Of the phosphates of lime : — 



The lowest . . . is . . . 

 The highest ....... 



The average of the whole number being 



We may bj-and-bye find occasion to return to a consideration 

 of this variety; but for the present we pass (m to the next analyses, 

 which are those of Patagonian guano. 



This variety usually contains more ammonia than the Saldanha 

 Bay guano, although in either case the quantity is very small. 



Nos. 66, 67, and 68, are samples taken from the top, middle, 

 and bottom of a cargo respectively, the analyses being by Dr. Ure ; 

 69 and 70 are duplicates of the same cargo; the analysis of 71 

 and 72 were made in my own laboratory ; the remainder are by 

 Mr. Teschemacher. 



Table 9. — PataRonian Guano. 



The highest per centage of ammonia is . .4*68 

 The lowest ,, „ ... 1-60 



The mean of the 14 specimens . . . .2*54 

 Of the phosphate of lime, omitting No. 66, which is so very 

 different from the other specimens, 



The highest per centage is 65*5 



The lowest „ 29-3 



The mean ,, 44*6 



In this variety of guano we have the state of things reversed ; 

 the relative proportion of earthy phosphates and of ammonia is so 

 changed, that the former constitutes the chief value of the manure. 

 Patagonian guano, then, is bought for its phosphates, not for its 

 ammonia, though, of course, the latter is not to be despised. The 

 same is true, in a greater degree, of Saldanha Bay guano. 



Saldanha Bay Guano. — Of this description of guano I shall 

 give first the analyses made under my own direction : — 



