APPENDIX.] FISH-GUANO. 495 



vertically in the interior of the pan. The boiling is completed in 

 an hour ; then by a simple movement the pan may be made to 

 swing upon its bearings, the steam allowed to escape, and the cover 

 being removed, the boiled fish is allowed to fall into a receptacle. 

 Workmen then convey it in baskets to the presses placed alongside 

 the boilers. 



" The great difficulty was to find a means of submitting this 

 fish-magma to the action of the press without losing the fine por- 

 tions. This was accomplished in this way : Under each of the 

 presses is placed a cylinder of sheet iron open at both ends, about 

 twenty inches high, and twelve inches in diameter. This cylinder 

 is strengthened by four small iron rings or hoops, and is pierced 

 with a number of very fine holes. A loose bottom or wooden plate 

 is fitted into this cylinder, which is then nearly filled with the 

 boiled fish, and upon this is laid another plate of wood similar to 

 the bottom. One or two blocks are then laid upon this cover, and 

 when all the cylinders are filled, a man turns alternately the screw 

 of each press. In proportion as the pressure operates, the water 

 and oil contained in the fish is seen to exude from the perforations 

 of the cylinder. These liquids flow into gutters which conduct them 

 to a common channel by which they flow into barrels placed under- 

 neath, and so graduated that when the first is filled, the overflow 

 passes into the second, and so on in succession, without the interven- 

 tion of any workman. After reposing for some time, the oil floats 

 on the surface, and is collected and stored in barrels in the cellar. 

 The average quantity of fish-oil thus extracted represents very 

 nearly 2| per cent of the fresh fish. 



" When the boiled mass is sufficiently pressed, the presses are 

 loosened, and the cylinders removed and turned upside down, close 

 to the reservoir, to allow any liquid which may have mounted to the 

 surface to flow away ; on then tapping the bottom wooden plate, the 

 pressed mass may be taken out of the cylinder in the form of two 

 compact cakes about four inches in thickness. These cakes are 

 immediately conveyed by a workman to the hopper of the rasp, 

 placed close at hand ; this rasp, set in motion by the steam-engine, 

 reduces the cakes to a sort of pulp, which is carried by children as 

 fast as formed to the stove. 



" The stove, situate on the first floor, is externally 20 metres 



