4 BULLETIN 150, U. S. DEPARTMENT OF AGRICULTURE. 



Table I. — Sources of nitrogen used in mixed fertilizers of the United, States. 

 (Figures are approximations.) 



Material. 



Amount 



used in j Nitrogen 



United content. 



States. 



Nitrogen 

 yielded. 



Ammonium sulphate 



Sodium nitrate (Chilean) . 

 Calcium cyanamid 



Cottonseed meal 



Fish scrap 



Tankage 



Dried blood 



Tons. 

 215, 000 

 85,000 



(High. 

 "\Low. . 



(High. 

 "\Low. 



(High. 

 ■\Low. 



681,000 



388,000 

 70, 000 



162,000 \ 

 99,000 I J 

 57,500 |\ 

 37,700 ! J 



Per cent. 

 19.75 

 15.5 

 18.0 



Tons. 

 42, 463 

 13, 175 



6.5 

 9.0 

 6.5 



11.0 



44,272 

 24,320 

 6,300 

 10,500 

 6,450 

 6,300 

 4,150 



This report is designed for the information of the layman who 

 is totally unfamiliar with the fish industries of the Pacific coast, of 

 those familiar with the fishing industries but not familiar with the 

 fertilizer trade, and particularly of those who are interested in the 

 manufacture of fertilizer from fish waste. For this reason all phases 

 of the subject are discussed, some of them in such detail as possibly 

 to appear extreme to those familiar with these details. Where such 

 details are omitted from this report, the literature containing them, 

 generally easily accessible Government reports, is referred to where 

 possible. The apparatus for use in rendering fish waste is discussed 

 in greatest detail, because, of all the items conneced with the indus- 

 try herein proposed and advocated, this is considered the one on 

 which information is most apt to be lacking and therefore most likely 

 to be desired. The writer has been assured of the willingness and 

 the desire of many of the operators of canneries to conserve the 

 by-products now lost as soon as they are informed of the proper 

 methods and apparatus to be used. An especial effort therefore is 

 made to present all available information concerning these, and to 

 discuss fully their advantages and disadvantages. 



TECHNOLOGY OF CANNING. 



FISHING. 



Salmon for use by the canneries are caught in traps or pound nets, 

 purse seines, haul seines, gill nets, and fish wheels. In southeast 

 Alaska the greater portion of the fish are taken in traps, owned and 

 operated by the packers, while in the Puget Sound region many are 

 caught with purse seines and gill nets. On the Columbia Eiver drag 

 seines, gill nets, and fish wheels are in general use. 



The traps or pound nets are designed to intercept the fish as they 

 swim in courses paralleling the shore or passing certain points. For. 



