ECONOMICAL GEOLOGY. 117 



valuable matter in relation to the manufacture of fish ma- 

 nure. He says the method of De Molen, a Frenchman, 

 "consists merely in boiling or steaming the fish until they 

 are disintegrated to a pasty massj then pressing them to 

 separate the oil, which is itself economized ; then drying 

 the cake left after this operation in a current of hot air; 

 and finally grinding it to powder. Pettit's patent process 

 involves the use of sulphuric acid, which is added to the 

 fresh fish, and has the same effect as steam in destroying 

 their consistence. After treatment with sulphuric acid, 

 the mass is pressed and dried as before. 



" De Molen has at present an establishment on the island 

 Kerpon, near the Straits of Belle Isle, which was fitted up 

 to employ one hundred and fifty workmen, and sends yearly 

 to France large quantities of Tangrum, as the product is 

 called. This name seems to be applied to the manure pre- 

 pared from herrings, or herring refuse. 



" At Concarneau (Finisterre) is also a large manufactory 

 offish-manure, in which, in 1854, the labor of six men and 

 ten children produced daily, for two hundred days in the 

 year, eight to ten thousand pounds of dry manure, from 

 thirty-six to forty thousand pounds of fish, or fish-refuse. 

 About half the supply of the raw material is the refuse of 

 the Sardine fisheries. Arrangements are making to in- 

 crease the product to eight thousand tons yearly. This 

 manure is sold at $35 a ton. It is represented to contain 

 twelve per cent, of nitrogen, equal to fourteen and a half 

 of ammonia, and six per cent, of phosphoric acid ; and is 

 considered much cheaper than Peruvian guano. 



"According to an article in the 'Practical Mechanic's 



