I60 MADRAS FISHERIES BULLETIN VOL. XIII, 



into direct and intimate contact with the gases, the moisture is 

 rapidly absorbed and driven off b}' the forced draught caused by 

 fan and chimney. Hence the drying is very rapid, a few minutes 

 sufficing; indeed the danger is of undue waste both by scorching 

 and carbonizing the material, and by driving off too much material 

 as dust by the chimney; watchful control is therefore necessary. 



It is obvious that the method is very economical since the 

 fuel gases are brought into direct contact with the material, and 

 where large masses — hundreds of tons daily — of very wet material 

 of a cheap and coarse character have to be dried, the method 

 commends itself as economical of time, space, and fuel. But it 

 is only applicable to materials of coarse character. 



26. The drying capacity of these driers is not clearly stated, 

 the two chief authorities differing radically. One authority gives 

 about 3 short tons (apparently dried scrap) per hour per drier, 

 whereas the other gives 600,000 to 8oo,000fish — weighing 200 or 266 

 short tons — per hour (sic) which would mean about 40 to 53 tons 

 dried scrap. Seeing that an ordinary factory with two presses and 

 one drier will only work off about 600,000 fish (yielding about 40 

 tons of dry scrap) per day of 12 hours, it would seem that the word 

 " hour " should be " day " in the second authority ; this would then 

 tally with the first; moreover the very largest factory has a maximum 

 dally capacity of 2,500,000 fish which, at 800,000 per hour, could be 

 worked off in 3 hours by a single drier; this is impossible. Hence 

 it may be taken that one average drier will turn out from 35 to 40 

 tons dry scrap per day of 12 hours with a coal expenditure in the 

 furnace of 5 tons, to which must be added the fuel required to 

 steam a 25 I.H.P. engine for rotating the drier. 



Steam driers are out of the question for this class of goods, but 

 the utilization of waste or exhaust steam or the hot gases from the 

 boiler furnaces would seem to be possible. 



27. As stated above, the material as it leaves the presses contains 

 about 50 per cent of water ; as it leaves the drier — whether drying 

 ground or hot blast — it may contain about 10 per cent and is then 

 commercially accepted as " dry " : in this condition it can safely 

 be stored without fear of decomposition or spontaneous heating. 

 With a larger content of moisture it must be used at once and— for 

 freight reasons also— in the neighbourhood. 



28. The yield of dry " guano" (scrap) is stated variously. The 

 average of 10 years over the whole Atlantic coast is stated at 



