Disc t_«v*1 
Feb. 14,1916 Apparatus for Measuring Wear of Concrete Roads 
953 
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■i 
Fig. i.—D etails of instrument for measuring the wear of roads: A, Heavy mortar block; B, light mortar block; C, steel rod; D, level adjusting screws; E, adjusting rack; F t inside 
micrometer; G, steel bearing block; H, electric buzzer- 
