No. 3 (1921) MANUFACTURE OF FISH OIL AND GUANO 



191 



been steady throughout ; the figures are taken fro:n the official Statistical 

 Reports of 1902 and 1906 : — 



The prices of the last few years are the average of 16 principal 

 towns for sardine and 23 for herring, and probably therefore slightly 

 lower than the price paid by the farmer. These later prices are extremely 

 high ; for after allowing i^ annas for phosphoric acid and taking N as 

 high as 10 per cent, the cost of the latter in 1904 ainounts to io'6 annas 

 per pound. Consequently, foreign sources of fish-manure are being sought, 

 large quantities of oilcake are coming in from China, together with 

 sulphate of ammonia and phosphates from other countries; the coal of 

 Japan is also, of course, now yielding sulphate of ammonia. It is 

 regrettable that the fishing industry has not been able to keep pace with 

 the demand for fish fertilizer which, in Japan, is the most esteemed of 



manures. 



(102) Fish-manure, like X, is essentially nitrogenous but contains 

 a larger proportion of phosphoric acid. It is of several kinds; the 

 ordinary sardine and herring simply dried in the sun on the sand ; scrap 

 which has been boiled and pressed for oil ; and a low grade made from 

 heads, vertebrae, offal, etc., of the larger fish. In 1882, the analysis of 

 samples from seven different sources gave an average of about 10 per cent 

 N and 4 per cent P.\, the variations being from 7 to 11 •? of N and from 

 3 to 4*85 (in one case 5*96) of PA ; the lowest figures were in all cases 

 taken from an inferior class of sardine simply dried on the sand and 

 containing a good deal of oil and sand , herring appeared to be superior 

 to sardine as a manure, and the best analyses were from herring scrap 

 from which oil had, at least in part, been removed. From 18S2, it is 

 believed that the general manufacture has improved, since the oil, a 

 valuable by-product but pos'tively harmful to the stuff as manure, is now 

 largely removed by boiling and expression ; sand, however, is Still a 

 trouble and specimens have been shown me in which sand formed 

 25 per cent of the sample, while even higher percentages are well known 



