Catalogue. A.H. Abbott & co., manufacturers and importers of mathematical and surveying instruments and drawing materials of every description .. (1896)
Abbott, A. H., & co., Chicago. [from old catalog] · [Chicago] · leaf 145
ments is an arrange-ment of the scale of altitude which admits reading of supervisions by a vernier, hitherto imprac-ticable, owing to the altitude scale in ordinary use being a gradually diminishing one, to whicha vernier cannot be applied. In the present instruments the action has been so… … No. 1006 Each. 1006. Mining Barometer, 5 inch, silvered metal dial, raised ringfor divisions, altitude 2,000 feet below and 3,000 feet abovesea level, with rack vernier scale reading to 1 foot, andmagnifying lens, in leather sling case $50 00 For mining purposes the entire circle of the dial is…
Drawing instruments
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