The microscope and its revelations . ope, allows thediaphragm-plate to be madeupon the ordinary plan (),since it can be brought suffi-ciently near to the lenses of thecondenser, without coming intotoo close contiguity with thestage ; and this is obviously thesimplest and most convenient ar-rangement. By Messrs. Powelland Lealand, agam,—their stage being too thick to aUow of the diaphragm-plate be-j:jg^_ 3g ing placed beneath it, without removing thatplate from its proper po-sition behuid the lensesof the condenser,—thediaphragm-plate is madeso small that it can bereceived into the interi
The microscope and its revelations . ope, allows thediaphragm-plate to be madeupon the ordinary plan (),since it can be brought suffi-ciently near to the lenses of thecondenser, without coming intotoo close contiguity with thestage ; and this is obviously thesimplest and most convenient ar-rangement. By Messrs. Powelland Lealand, agam,—their stage being too thick to aUow of the diaphragm-plate be-j:jg^_ 3g ing placed beneath it, without removing thatplate from its proper po-sition behuid the lensesof the condenser,—thediaphragm-plate is madeso small that it can bereceived into the interiorof the stage (Fig. 37),but is rotated by amilled-head beneath; andthe edge of this is markedby numbers, each signify-ing a particular aperture,and thus marking by itsposition toliich apertureis in use. As, however, the smallness of the diaphragm-plateso hmits the number of apertures, that the desirable_ varietycould not be afforded by it alone, a second plate is madeto rotate immediately beneath it upon the same axis (like the. Smith and Becks Achiomatic Condenser. ACHEOilATIC COXDEXSER.—EEFLECTIX& PKISIMS. 127 hoiir and minute-hands of a Tvatch), by means of a secondmilled-head, numbered at its edge like the first; and theapertures in the diaphi-agm-plate being simple circles, the Fig. 37.
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Keywords: ., bookcentury1800, booksubjectmicroscopes, booksubjectmicroscopy
