unt as its great rival Oregon pine, which was re- and builders in general. duced by 5% of an inch. In carrying out the tests the specimens were a cemented to identical blocks of sandstone, each of A VALVE TESTING AND LOCKING DEVICE. which weighed twenty-one pounds. The samples pre- The illustration… … materials which remained intact, and the clear space ing devices partly in section. The improvement has beneath shows the amount that was worn away by the been patented by Heinrich G. Borgfeldt, 850-852 Broad- the engineer to readily determine whether the valve on wheel. way, Brooklyn, N. Y. The…
Internet Archive · Public domain (published before 1931). Free to use for anything.
