156 MADRAS FISHERIES BULLETIN VOL. XIII, 



enables the vessels to get back to sea with the minimum cost of 

 time, wages, etc. But it requires an engine of about 25 I.H.P. 



16. As the fish come up from the hold they pass through a 

 machine which either weighs or measures the quantity of fish. 

 Though menhaden are spoken of in numerical terms, viz., so many 

 million of fish, they are not counted but weighed or measured ; the 

 accepted standard size of a fish is 22 cubic inches, so that a 

 compartment of 22,000 cubic inches is supposed to hold 1,000 fish ; 

 as a matter of fact a " thousand " may be 500 or 2,000 fish according 

 to the size of the fish. The weight of a "thousand" is conven- 

 tionally estimated at 666 lb. so that three " thousand " weigh an 

 American ton of 2,000 lb. These considerations are of importance 

 in comparing the output of oil and guano with that of Madras 

 sardines : it is further to be remembered that the U.S.A. gallon is 

 only five-sixths of a British gallon of 10 lb. water. 



17. From the weighing machine a conveyor takes the fish to 

 the " raw box " or receiving bin which is often of enormous size ; 

 the depth is usually 10 to 12 feet, but the length and breadth of 

 the largest in use is said to be 225 x 25 feet. The sides of these 

 bins slope to the centre where a covered trough is traversed by a 

 conveyor; by removing parts of the cover of the trough, the fish 

 fall into the conveyor which takes them to the cookers. 



18. Cookers.- -The object of cooking is to break up the tissues 

 and oil cells, and thus free the oil for remov.il; moreover, it not 

 only does in a few minutes what took weeks by the old putrefactive 

 method, but yields a far superior oil free from putridity, of fine 

 colour, and comparatively valuable. 



The old kettle with open fire and hand press soon gave way 

 to the vat with steam heating ; these vats, usually of wood, are 

 partially filled with water, and are provided with false perforated 

 bottoms below which are coils of perforated steam pipe; the fish 

 are dumped into these vats, and the jets of steam, at perhaps 30 or 

 40 lb. pressure, not only boil the fish with great rapidity, but break 

 up the fish and fat cells by their forcible impact. Sufficient water 

 is provided to form a fluid medium through which the lighter oil 

 ascends to the surface, where with the upper stratum of water it 

 can be skimmed off either by hand, or by orifices and pipes at 

 suitable level, or by a jointed swivel pipe. Sometimes these vats 

 are of great size and the boiled mass is then left in them for two 

 or three hours and the surface stratum of oil with water is run off. 



