. The Pharmaceutical era. lined sur-face of the prisms silvered, except for an ellipticalspace in the center, and the two prisms cementedtogether again. This is fastened in a mountingabove the ocular in such a position that a free andequally illuminated view of the field of the micro-scope is afforded through the unsilvered opening inthe prism. Prom the side of the mounting extendsa bar which supports a movable mirror which re-flects an image of the drawing paper and the pen-cil point into the upper prism, whence it is reflectedby the silvered surface to the eye, seemingly co-inciding with the
. The Pharmaceutical era. lined sur-face of the prisms silvered, except for an ellipticalspace in the center, and the two prisms cementedtogether again. This is fastened in a mountingabove the ocular in such a position that a free andequally illuminated view of the field of the micro-scope is afforded through the unsilvered opening inthe prism. Prom the side of the mounting extendsa bar which supports a movable mirror which re-flects an image of the drawing paper and the pen-cil point into the upper prism, whence it is reflectedby the silvered surface to the eye, seemingly co-inciding with the field of the microscope as seenthrough the opening in the silvered surface of two fields should be equally illuminated, otherwiseolijects in the one least illuminated will seem faint andindistinct. If the image in the microscope is too brightit may be toned down, either by narrowing the aper-ture in the diaphragm, or by placing a piece of whitepajier over the mirror. When the image of the drawing -- - - -i ^. Fig. 25.—Sub-Stage, Showing Condenser and Iris Diaphragm. 394 THE PHARMACEUTICAL ERA. [March 17, 1898.
Size: 1955px × 1278px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectdrugs, booksubjectpharmacy, bookyear1
