R. & J. BECK MICROSCOPE-WALE DIAPHRAGM

YEAR: c. 1886

SIGNED: R. & J. BECK, LONDON & PHILADELPHIA   and also  WALMSLEY & C^o, PHILADELPHIA, SOLE AMERICAN AGENTS

SERIAL NUMBER: 15430

MODEL: ECONOMIC

Compare the engraving of the Wale invention with the Beck version as shown here. The Beck version was meant to be removeable from the understage sleeve to allow other accessories to be used there; George Wale's version was meant to remain in place. The Beck version uses a pin-in-spiral slot mechanism to move in and out whereas Wale used a screw thread on the lower part. The image on the right illustrates the surprising range of openings that the Beck version of the Wale diaphragm has. See also the original Wale diaphragm.