Technical supply co., Scranton. [from old catalog] · Scranton, Pa., Technical supply co · leaf 370
n PORTABLE AIR METER … 4305 For the measurement of air-currents through mines, tunnels, sewers,and the ventilation of hospitals, public buildings, etc. The indications areobtained by means of a delicately poised fan wheel, the recordings beingcommenced by the long hand, which traverses the outer circumference of themain…
Engineering instruments · Drawing instruments
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
