Practical draughtsmen's work, with numerous engravings and diagrams (1903)
Hasluck, Paul N. (Paul Nooncree), 1854-1931, ed · Philadelphia, D. McKay · leaf 50
ther there will be found one position, whenthe eye is about 9 in. from the paper, at which the left-hand dotvanishes ; at all other positions both dots can be seen at the DBAWING STRAIGHT LIJSfES. 47 same time, although the eye is directed to the right-hand oneonly. This is owing to a small part of…
Mechanical drawing
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
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