... Report on the building and ornamental stones of Canada, vol. I-V (1912)
Parks, W. A. (William Arthur), 1868-1936, Canada. Mines Branch · Ottawa : Government printing bureau · leaf 164
ctuated by electricity. After various trials thecompany has decided to use that tj-pe of drill and channeler which is actuateddirectly by air which is compressed individually for each machine by a smallelectrically driven compressor. At the time of my visit 15 machines of thiskind were in operation…
Building stones
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