164 GEOLOGY OF OHIO. 



twenty-six varieties of repressed material tested, showed a loss in rattling 

 of 17.92 per cent, while the plain bricks,, (nineteen varieties) showed a loss 

 of 17.42 per cent. Also the tests of the various brands of brick manu- 

 factured at Canton, Ohio, (which were all furnished both repressed and 

 plain, and which are included in the general average given above) show 

 in the rattling test as follows : 



Repressed — Loss, 16.43 per cent. 

 Plain side-cut^Doss, 16.68 per cent 



A special test was made on material submitted by the Holloway 

 Paving Brick Co., and seven repressed brick and eight plain brick were 

 given 1,000 revolutions together in the rattler with a loss of 



Repressed, 15.02 per cent. 

 Plain, 19.56 per cent. 

 Also, in the same test, one repressed brick each from Canton, Royal, 

 and Williams factories at Canton, were rattled with two each of the, same 

 factories, plain. The results here showed, 



Repressed, 11.45 per cent. 

 Plain, 10.12 per cent. 



The total average loss of all four brands of paving brick in this 

 special test of 1,000 revolutions showed : 



Repressed, 13.23 per cent 

 Plain, 14. 84 per cent 



This difference is not great, and the fact that the plain bricks would 

 lose their square corners and edges very rapidly, while the rounded edges 

 of the repressed brick would last some time before the skin would break, 

 indicates that in the average there is little to choose between the two in 

 point of toughness and resistance to abrasion. 



This test, however, is a very hasty and inconclusive one : it is merely 

 an indication, not a proof; to. make the results conclusive, two kinds of 

 brick should be made so that every other condition except the pressing 

 should be exactly the same. They should be made of the same clay, at 

 the same time, dried alike, burnt in the same course of the same kiin 

 Such material was not procurable however, and the tests as made simply 

 represent the run of the yard, when they were selected. 



The test which is, recommended is a very easy one to make, and is 

 within the reach of any. paving brickmaker without expense. The 

 truth of the matter could in this way be easily ascertained. 



The method of repressing is much the same everywhere. The bricks 

 are taken as directly as possible from the separating belts, cars or pallets, 

 and fed to a repress machine by a feeder— and the machines now in use 

 are arranged to automatically receive, press and deliver the finished 

 block. Two machines at present are in use in the state. 



1. The Raymond Repress, of Dayton. 2. The Eagle Repress, 

 by the Frey Sheckler Co., of Bucyrus. 



