140 THE WAREHOUSING OF GRAIN. 



of 125 pounds through the return pipe in the staircase, 

 there being a hydrant on each landing. 



The bands are 20 inches wide and are made of two-ply 

 canvas and india-rubber. Each band is capable of conveying 

 about 75 tons of grain per hour. The upper or loaded part 

 of the bands runs on steel rollers fixed, in the case of those 

 in the tunnel, 6 feet 9 inches apart, and the return or empty 

 part which runs underneath is also supported by steel rollers 

 fixed, however, 13 feet 6 inches apart. The rollers have 

 cast-iron spindles tapered at the ends. The weight of a 

 roller and spindle is between 14 and 15 pounds, which is 

 almost exactly the weight of beech rollers used by Arm- 

 strong & Co. The usual practice, however, of that firm is 

 to use varnished yellow pine rollers. The spindles are 

 supported on bearings of white metal run into cast-iron 

 brackets, and are fitted with iron lubricators with heavy 

 iron covers. These brackets rest on cast-iron frames 

 securely bolted to the floor and are connected together by 

 angle irons, one on each side. The travelling feed hoppers 

 and " throw-oif " carriages run on these angle irons. The 

 travelling feed-hoppers are provided with inclined rollers 

 on each side of the band. Each band is provided with a 

 tightening apparatus. In the machinery floor this is effected 

 by means of a sheave with sliding carriage and weights 

 moving between wrought iron guides. In the tunnel, as 

 there is no room for weights hanging under the floor, a 

 tightening screw is used instead. Bands are aifected 

 greatly, as regards extension or contraction, by the degree 

 of moisture in the air. In damp weather the bands con- 

 tract, and in dry weather they expand. 



It is a matter of great importance that the rollers should 

 revolve when the band is in motion, otherwise the roller 

 gets worn flat where the band passes over it. To insure 



