268 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



tons dried, with a total selling value of $1,539,810. Of the 45,711 tons 

 produced from Delaware northward, 33,458 tons were acidulated and 

 12,253 were dried, the average price of the former being $12.87 per 

 ton and the latter $26.22 per ton. South of Delaware the product of 

 green and of acidulated scrap combined, according to the latest 

 returns, was 15,395 tons, while 24,724 tons were dried, the respective 

 values per ton being 112.95 and 123.79. 



Only a small percentage of the fish scrap is used by the farmers in the 

 condition in which it leaves the factories ; most of it is ground and 

 serves as an ingredient in compound or so-called " complete " ferti- 

 lizers. Compound fertilizers are prepared at some of the menhaden 

 factories, but as a general thing their preparation is in the hands of 

 persons who have nothing to do with catching and rendering the fish. 



The value of commercial fertilizers is dependent mainly on their 

 content of nitrogen and phosphoric acid, which are the most impor- 

 tant plant foods usually lacking in the soil. The nitrogen necessary 

 is supplied mainly by fish scrap. Various other materials are also 

 used, as dried blood, meat scraj) and other slaughter-house refuse, 

 cotton seed, sulphate of ammonia, nitrate of soda, Peruvian guano, etc. 

 The phosj)horic acid is supplied hy fish scrap to some extent, but 

 principally by the phosphate rocks, boneblack from tlie sugar refin- 

 eries, bone meal, etc. , the solubility of the phosphate being increased 

 by treatment with sulphuric acid, thus making superphosi)hates. 

 The value of fish scrap varies according to the percentage of ammonia 

 and x^hosphoric acid contained therein. As a general rule, dried scrap 

 contains about 8 per cent of nitrogen and 8^ per cent of phosphoric 

 acid. On a selling basis of 124 i^er ton, the nitrogen costs about 10 

 cents per j)ound and the phosphoric acid about 3^ cents j)er pound 

 for comiiounding purposes. Other necessar}^ plant foods are potash, 

 lime, magnesia, sulphuric acid, and iron. These usuallj' exist in suf- 

 ficient quantities in the soil itself, but arc added under special con- 

 ditions, esi)eciall3^ the jiotash. The natures of the ingredients and the 

 respective proportions required vary according to the soil and tlie 

 crop for which the compound is intended. 



Although the agricultural value of dried fish scrap is nearly equal 

 to that of Peruvian guano, the market j)rice is much below that arti- 

 cle. In explanation of this fact it may be stated that fish scrap is not 

 in such compact and good mechanical condition for sliipment and gen- 

 eral use. Its value as a fertilizing agent has not been so widely Icnown 

 as that of Peruvian guano, and thus its princii)al use is lai-gely limited 

 to the manufacturers of superphosphates, wlio are forced bj- compe- 

 tition to exercise great caution in the cost of manufacture. And, 

 furthermore, there is a tendency to reduce the quantity of ammonia and 

 increase that of phosphoric acid and potash in complete fertilizers to 

 meet the i-equirements of the soil. Other ammoniated materials now 

 compete with fish guano in the nuiking of superphospliates, among 



