GRAIN TANKS. 169 



water, it will clearly pay to put wheat into huge canisters 

 of iron. The wheat canister, in short, should be a wrought 

 or cast iron tank of greater or less size, according to the 

 wants of the owner, whether for the farmer's crop or the 

 grain-merchant's stock. This tank should be constructed 

 of small parts, connected together by screw bolts, and con- 

 sequently easily transported from place to place. The in- 

 ternal parts should be galvanised, to prevent rust, and the 

 external parts also, if desired. It should be hermetically 

 tight at all the joints, and the only opening should be 

 what is called a man-hole that is to say, a canister top 

 where the lid goes on, large enough to admit a man. When 

 filled with grain, the top should be put on, the fitting of 

 the edge forming an air-tight joint. Wheat put dry into 

 such a vessel, and without any vermin, would remain wheat 

 any number of years. But an additional advantage to such 

 a reservoir would be an air-pump, by the application of 

 which, for the purpose of exhaustion, any casual vermin 

 would be killed. If the grain were moist, the same air- 

 pump might be used to draw or force a current of warm air 

 through it, to carry off the moisture. By this process, and 

 subsequently keeping out the air, the grain might be pre- 

 served for any length of time. As the reservoir would be 

 perfectly air-tight and water-tight, it might be buried in 

 the ground with perfect safety ; and thus cellars might be 

 rendered available for granaries, economising space of com- 

 paratively little value. The grain would be easily poured 

 in from the surface, and to discharge it an Archimedean 

 screw should be used. The size of the reservoir should be 

 proportioned to the locality, and it should hold a specified 

 number of quarters, so as to serve as a measure of quantity, 

 and prevent the expense of meterage. ... If con- 

 structed above the ground, a stair or ladder must commu- 

 nicate with the upper part, and the lower part must be 

 formed like a hopper for the purpose of discharge. For 

 many farm localities this arrangement might be best, and 

 wheat might be thrashed into grain direct from the field, 

 and stored. . . . Granaries of this description would 



