318 BOARD OF AGRICULTURE. 



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 here- 

 after 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 advisable, for all parties pecuniarily interested in the fish 

 guano manufacture, to favor a closer scientific investigation 

 into the changes, which the menhaden fish undergoes during 

 the customary mode of rendering. 



Loss of nitrogenous matter, in consequence of misapplica- 

 tion 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 propor- 

 tion, reduces, to say the least, the commercial value of the 

 guano by adding a worthless 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 sub- 

 sequent analytical 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 substitutes 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 

 improvements 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 overstocking of our fertilizer markets 



