Journal - Franklin Institute of the State of Pennsylvania (1826)
Franklin Institute, Philadelphia, Franklin Institute (Philadelphia, Pa.) · [Philadelphia : Franklin Institute] · leaf 419
is possible to accomplish the drilling of rock by the per-cussive principle (which is the only true one), by an electric 388 Saunders: [J. F. I.. engine which will be equal in weight, in price and efficiencyto an air engine. The weight of a rock drill is one of itsmost conspicuous limitations, and… … Fig. 9.price with iron, and the durability of the apparatus isapparently in favor of the air drill. But as mines are likelyto be lighted by electricity, and as there are many conditionsof work favoring electric transmission for other purposes,we here have a means by which all the advantages of…
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