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 110
ale into two symmetrical halves. Therunner or indicator moves backward and forward on the rule, and shows down the center a fineblack line, for the purpose of reading the results. Is useful for ascertaining percentage, square and cubic contents; square root and cuberoot; proportions; comparison of… … 8<M). Patent Polar Planimeter, of German silver, for computing areas, with brass weight, in case ISO 00 Polar Planimeter, to measure only square inches, in case 15 50 The Polar Planimeter is a very important instrument (or detetermining the area oi Irreg-ular figures, such as railroad profiles,…
Drawing instruments
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