FISH-SCEAP FEETILIZEK INDUSTRY OF ATLANTIC COAST. 29 
again by bucket conveyer, to the warehouse where it is stored, 
ground, and bagged. The transit through the drier consumes from 
3 to 20 minutes, depending on the force of the blower, the rate of 
rotation of the kiln, and the degree of fineness of the lumps of scrap 
on entering the kiln. The moisture content is reduced to about 7 
per cent. As some of the kilns are being operated, about 5 tons 
of coal per day is consumed. According to the various estimates 
of the operators, a million fish produce 75 to 85 tons of dry scrap; 
12,000 to 15,000 fish are required to make 1 ton of scrap. The drier, 
complete and set up, may be purchased for $3,000, inclusive of blower, 
bricks, etc. 
The hot-air drier for fish scrap is a useful piece of apparatus, 
and its introduction marks an epoch in the fish-scrap industry. It 
has rendered it almost altogether unnecessary to acidulate scrap, since 
the drier practically always is able to handle the output of the cookers 
and presses. In the plant equipped with a full set of the improved 
machinery the fish are not moved by manual labor from the time 
they are fed to the elevator in unloading until the dry scrap is being 
bagged. The whole operation requires less than an hour. 
Theoretically, the hot-air drier is inefficient. Theory requires that 
in drying the drying agent shall be passed over the material being 
dried in a direction opposite to that in which that material is moving. 
Thus, in drying by a stream of hot air, the hottest and driest air is 
brought into contact with the driest material, and as it becomes more 
heavily charged with water vapor, passes progressively over wetter 
and wetter material. In this way the maximum moisture absorbing 
power of the air is made of use. In the drier in use in the fish-scrap 
industry, the opposite arrangement obtains, the hottest and driest 
air is brought into contact with the wettest and coldest fish, and the 
wettest and coldest air into contact with the driest and warmest 
fish. The objection raised to the former procedure is that the dried 
scrap is inflammable and a careful regulation of the temperature 
would be required to prevent the scrap from catching fire. There 
is little danger of this with the present scheme. However, it would 
be a simple enough matter to lower the temperature of the drying 
gases far below the ignition temperature of the dried scrap by intro- 
ducing a sufficiently large volume of cold air into the gases from the 
furnace ; or the fire could be largely reduced in size. Certainly the 
same amount of drying could be effected with a smaller consumption 
of coal, or with the same consumption of coal more efficient drying 
and. possibly, more rapid drying could be made possible by the use 
of a larger volume of air, and the process could be made as auto- 
matic as the present process. 
A more serious objection to the present practice in drying scrap 
is the undoubted destruction of a part of the scrap in the drying. 
