A device used to transfer drawing onto opaque paper using bright tin, two showcase lamps, and plate glass. The drawings can be copied in pencil on heavy paper or Bistrol—board.

Transparent Drawing Board

A device used to transfer drawing onto opaque paper using bright tin, two showcase lamps, and plate…

A blue print frame used to make copies of mechanical drawing. The process is done by exposing a sensitized paper in contact with the tracing paper to the light source in the frame. A chemical reaction takes place when washing with water to create a strong blue color, creating the image.

Blue Print Frame

A blue print frame used to make copies of mechanical drawing. The process is done by exposing a sensitized…

Pair of circular pulleys connected b a cord, showing the range of motion as arcs

Pulley

Pair of circular pulleys connected b a cord, showing the range of motion as arcs

"An instrument which, when applied over an artery, traces on a piece of paper moved by clockwork a curve which indicates the changes of tension of the blood within... a, band by which the instrument is fastened on; b, spring which rests upon the artery; c, adjusting-screw (with graduated head) which regulates the pressure of the spring b according as the pulse is strong or weak; d, d, supports for paper upon which the tracing is made; e, e to engage the paper positively; g, small spring clockwork (incased) by which motion is imparted to the feed-roller e1; h, milled-headed winding key; i, stop-motion; j, tracer attached to the oscillating arm k, which is moved by the rod l that connects this arm with the spring b." —Whitney, 1889

Sphygmograph with All Parts Labeled

"An instrument which, when applied over an artery, traces on a piece of paper moved by clockwork a curve…