Technical supply co., Scranton. [from old catalog] · Scranton, Pa., Technical supply co · leaf 164
RICHARDSON SLIDE RULE (Direct Reading) … For Engineers, Electricians, Draftsmen, Estimators, Business Men To read this rule a knowledge of logarithms is unnecessary, and itcombines in one simple instrument most of the information the practical manneeds for ordinary problems. No wood enters the construction of the Richardson rule.…
Engineering instruments · Drawing instruments
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