FERTILIZERS. 39 



potash-bearing mineral, they therefore need to be used 

 with some care, lest the proportion of salt present injure 

 the roots of growing plants. 



There is another waste of the fisheries which has come 

 into the market of late years : I refer to the skins, bones, 

 and tins of salted fish. These come from the fish that 

 are stripped, and sold, boxed, free of bones. It is a heavy 

 article, and the strips come a little tangled. Fertilizer 

 manufacturers usually monopolize this ; though it can 

 sometimes be picked up at Gloucester, Mass., at from 

 $3.75 to 115 per ton. 



Dog-fish, which is another name for a small species of shark, 

 in the summer season swarm along the New-England coast, 

 on the inner fishing-banks, driving away most other varie- 

 ties. They weigh from three to five pounds. They are 

 very easily caught, and, their muscles being very firm, are 

 rich as manure. The great trouble in manipulating these 

 has been because, the flesh being of a sticky and oily na- 

 ture, acid will not readily act on it. Still, they are used 

 very largely, as a source for ammonia, by one large fertil- 

 izer -manufacturer in the vicinity of Boston, who composts 

 them with horse manure, and, I infer, lets his compost 

 heaps remain two years before using, when the objection 

 disappears. Being so abundant along the coast, and so 

 cheap, being sold, wholesale, at $1 a hundred fish, they 

 are well worthy the attention of farmers who live along 

 the shore ; for, though it might be necessary to keep them 

 over a year, the investment would pay an interest of some 

 hundred per cent. The fishermen in many localities would 

 catch them if there was a market for them. The oil from 

 the livers averages about a cent each fish ; and, with one 

 cent from the livers and another for the fish itself, quite a 

 fair business can be done during the hot months. 



Waste salt that has been once used on fish contains in 



