UNUTILIZED FISHERIES RESOURCES 55 



able cone, located at the discharge end of the casing, passes the material 

 out of the press. The hollow screw shaft is provided with special coni- 

 cal perforations permitting steam to mingle with the material while it 

 is being pressed. The steam not only heats the material but keeps it 

 soft and thus permits more easy separation of the liquids from the solid 



material. 



i 



Heavy worm-gearing rotates the main shaft and the thrusts from 

 the screw and the worm are taken up by carefully designed. bearings 

 and thrust-collars. A conveyor carries the pressed and cooked material 

 to the drier, which is a hollow steel cylinder mechanically devolving. 'A 

 series of parallel steel tubes arranged in the form of a ring, and with a 

 central open, horizontal space, rotates inside the cylinder around with 

 it. . These tubes are supplied at one end with steam for drying, and in 

 order to throw the material about and expose it to the hot tubes, a num- 

 ber of radial shelves project along the entire inner surface' of the. 

 cylinder. These shelves not only scatter the wet material over the 

 tubes, but carry it as it dries towards the discharge end, where it leaves 

 the machine through a special exit in the steel shell. The water in the 

 shape of vapour, arising from the wet material during its progress, is 

 drawn off by a large vapour-flue placed in the feed end of the machine. 

 It will be seen from this brief description that the whole process is 

 automatic and it can be accommodated in a rough wooden shed. An 

 engine and boiler are, of course, necessary and as a rule a conveying 

 apparatus is added, thus reducing the amount of manual labour to a 

 minimum. The fuel used may be either gas, coal or oil, and the final 

 product is what is called granulated fish-scrap, from which most of 

 the liquid'^and oil have been extracted. The oil is treated separately and, 

 if the material is fresh, is of excellent quality and much in demand. It 

 will be seen that, apart from the fish-scrap and oil, no other products 

 result from this process. The production of glue is a somewhat tech- 

 nical matter, and requires special expert skill to extract. As a rule, 

 about eight tons of raw material are required to produce one ton of 

 scrap and 8 to 12 gallons of oil may be produced from a ton of raw 

 dog-fish. 



Products Obtained from Dog-fish 



The reduction plant was manufactured by the Amer- 

 aniTon''^ ican Process Company and has been found very 



successful. Each plant can handle thirty tons of raw 

 material. The fishermen are paid $4.00 a ton for dog-fish. That is a 

 rather high price but they will not bring the fish in for less. They are 

 paid $2.00 a ton for other fish offal. An analysis of the scrap pro- 



