222 MADRAS FISHERIES BULLETIN VOL. XIII, 



hermetically — has not usually been dried ; the addition of this 

 process is desirable since steam is available ; it is only necessary 

 to fit a closed coil — copper preferably, but a grid of strong iron 

 pipes will do — to one of the tanks. In fact, a drier on this principle 

 was made for the writer in London and is now at Tanur, being a 

 vertical, galvanized steel cylinder, provided with an externally 

 tinned copper steam coil (closed) which traverses it internally from 

 top to bottom ; the oil in a small stream from a slightly elevated 

 tank is let in at the bottom and rising slowly in the cylinder is 

 heated to above 212° F. by the steam coil and issues dried and 

 sterilized from an outlet tube at the top whence it can be directed 

 at once into storage vessels. As the steam coil is closed the steam 

 does not come in contact with the oil. 



120. As elsewhere shown, the practice, when carried out in the 

 coast factories, is to pour the oil into a vessel and heat it by open 

 fire ; this leads to serious loss, since much of the oil must be, and 

 is, scorched, so that oil is wasted by carbonization and seriously 

 damaged in odour and colour ; hence a low price. If steam is not 

 available it is always possible to heat the oil above the point of 

 boiling water, 212° F. and thus to drive off any water, by putting 

 the oil into thin metal receptacles, e.g., kerosene tins, and placing 

 these tins in a bath of strong brine, preferably of calcium chloride, 

 which is heated by an ordinary open fire or furnace; the brine 

 attains a heat considerably above 212° F. and consequently also 

 raises the oil in the tins to a similar temperature, so that any 

 water in it is driven off. Brine from calcium chloride is better 

 than brine from common salt since it does not attack iron ; more- 

 over it can be raised to a very high temperature if the solution is 

 strong ; the material is very cheap. But common salt has the 

 advantage of being always at hand. 



All oil should, after careful separation, be deprived of any 

 residual, suspended moisture by heating as above, viz., either by 

 steam or by treatment in a brine bath. 



121. Proper storage. — The fifth point is storage. If well purified 

 dry oil, free from moisture, is properly stored, it will remain 

 perfectly good and sweet indefinitely; if such oil is improperly 

 stored it is apt gradually to go rancid ; if oil is not properly purified 

 and freed from moisture it will certainly deteriorate but the amount 

 and rapidity of such deterioration may be minimised by good 

 storage. In illustration of the above it may be mentioned that 



