234 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



the fish are fresh, the resulting oil is usually clear, bright, and com- 

 parativel}^ odorless and tasteless; and according to the extent of the 

 decomposition the oil becomes darker in color until it approaches a 

 very dark brown. However, this is not always the case, for perfectly 

 fresh fish sometimes yield dark oil. 



The standard grades recognized for crude oil are A, B, C, and D; 

 these terms being synonymous, respectively, with extra light crude, 

 light crude, brown crude, and dark brown crude. The bulk of the 

 output is of A grade, and little D oil is now prepared except in the 

 Southern factories. 



In the process of refining, menhaden oil is first heated and then, 

 placed in barrels and chilled in the manner already described for 

 whale oil, either by exposure during cold weather or by refrigeration. 

 This chilling grains the oil, the thick parts collecting together and the 

 limpid oil forming globules. The grained oil is then placed in bags 

 made of coarse material, and these carefully arranged one above 

 another in a press. On applying compression, the thin oil comes 

 out first and the impurities and stearin are left behind. The oil 

 is then placed in shallow vats or tanks, exposed to the rays of the sun 

 and protected by a glass covering, where it remains for a day or two. 

 It may also be clarified by treating it with caustic soda and acids, 

 resulting in a short time in a clear, light-straw color. 



The pressing of the oil in CQnnection with its refinement may be 

 done at a summer temperature, but in that case only a portion of the 

 foots are extracted and the oil has a poor weather-test. The usual 

 weather pressing during the summer yields 5 per cent of foots, and the 

 oil stands a temperature of about 50° F. If pressed at a temperature 

 of 32° to 35° F., the foots extracted represent about 10 per cent of the 

 original bulk. The foots are used as a substitute for tallow in leather- 

 currying and also in soap-making, the market price approximating 3 

 cents per pound. 



The products from refining menhaden oil are pressed extra light, 

 pressed light, jjressed light brown, pressed dark brown, bleached, 

 extra bleached, oil foots or pressings, bleached oil foots, extra bleached 

 oil foots, and menhaden oil soap. The first four grades of pressed oil 

 are obtained respectively from A, B, C, and D grades of crude oil. 

 A difference of about 1 cent per gallon exists between the prices of 

 each of these consecutive grades of pressed oil. The pressed light 

 is the standard grade, and when that sells at 30 cents per gallon the 

 pressed extra light sells at 31 cents, the pressed light brown at 29 and 

 the pressed dark brown at 28 cents per gallon. On the same basis the 

 bleached sells at 33 cents per gallon, the extra bleached at 35 cents; 

 and the same oils pressed at a low temperature sell for 1 or 2 cents 

 more per gallon. A corresponding price for the unbleached foots 

 is 2^ cents per pound; bleached foots, 'S^ cents per pound; extra 

 bleached foots, 4 cents, and menhaden-oil soap, 4 cents. 



The names "straits oil" and "bank oil" were formerly applied to 



