222 RKPORT OF COMMISSIONER OF FISH AND FISHERIES. 



"To produce a fish guano which contaius in a given quantity the largest 

 possible amount of nitrogen, must be the principal aim of the manufac- 

 turer. It brings the highest pecuniary compensation ; for one percent- 

 age of nitrogen is commercially equal to 4 per cent, of phosphoric acid. 



" During the past, it is true, there has been little inducement for con- 

 siderations of this kind on the part of the manufacturer, because prac- 

 tically there has been scarcely any serious discrimination on the part 

 of the consumers regarding the exact relative chemical composition of 

 the various fish guanos offered for sale. 



" The future prospect of this branch of home industry depends, in an 

 unusual degree, on the exertions which hereafter shall be made, on the 

 part of the manufacturers, to meet the present more exacting conditions 

 of the trade in fertilizers. 



"To derive any full benefit from the capital invested renders it ad- 

 visable, for all parties pecuniarily interested in the fish guano man- 

 ufacture, to favor a closer scientific investigation into the changes 

 which the menhaden fish undergoes during the customary mode of ren- 

 dering. 



" Loss of nitrogenous matter, in consequence of misapplication of heat, 

 seems to be not always compensated for by an increase of the yield in 

 oil. 



" The latter, when left in the fish mass in an undue proportion, reduces? 

 to say the least, the commercial value of the guano by adding a worth- 

 less matter, which may affect seriously the analytical results, as far as 

 its percentage of nitrogen is concerned. To heat the fish to a higher 

 temperature, or for a longer period of time than is required to secure 

 the largest possible amount of oil, reduces, invariably, the commercial 

 value of the fish mass for agricultural purposes. A few subsequent an- 

 alytical statements, regarding the composition of fish, and the degree 

 of the changes which they may suffer by steaming and rendering, may 

 serve as a practical illustration of my previous remarks. 



"A well-dried and finely-ground fish guano is one of our best substi- 

 tutes for Peruvian guano, and ranks equally high with the best quality 

 of animal dust from our butcher refuse establishments. It deserves the 

 liberal patronage of farmers wherever a rich nitrogenous phosphate is 

 called for. 



"I have shown in a previous report, that, as a general rule, the high 

 grades of superphosphates are cheaper than our low grades ; the same 

 rule applies to nitrogenous materials. 



" The recent changes in our fertilizer trade tend to stimulate improve- 

 ments in the modes of their manufacture, by rendering true merits 

 prominent, which, as a natural consequence, secures a reliable patronage 

 only to the best quality. We are not yet suffering from an overstock- 

 ing of our fertilizer markets on account of overproduction of home-made 

 fertilizers obtained from suitable home resources. 



" Millions of dollars are annually sent abroad still, for the importa- 



