Memoirs of the most eminent American mechanics : also, lives of distinguished European mechanics : together with a collection of anecdotes ... relating to the mechanic arts : illustrated by fifty engravings (1852)
Howe, Henry, 1816-1893, New York Museum of Science and Industry. Library · New York : Harper & Brothers · leaf 363
these two threads, being liketwo small circles enclosed by a third, occupied but one half of thespace of the hole. The conical awl was then flattened, and had an oval form as toits section given to it; and some time afterwards the awl was sofiled as to give it four faces, the section being…
Industrial arts · Inventors
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