. The microscope and its revelations. been devised. Where, on the other hand, LENS-HOLDERS 2$ I portability may be altogether sacrificed, and the instrument is to beadapted to the making of large dissections under a low magnifyingpower, some such form as is represented in fig. 203 constructed byMessrs. Baker, on the basis of that devised by Professor Huxley forthe use of his Practical Class at South Kensington, will be founddecidedly preferable. The framework of the instrument is solidlyconstructed in mahogany, all its surfaces being blackened, and is >»arranged as to give two uprights for
. The microscope and its revelations. been devised. Where, on the other hand, LENS-HOLDERS 2$ I portability may be altogether sacrificed, and the instrument is to beadapted to the making of large dissections under a low magnifyingpower, some such form as is represented in fig. 203 constructed byMessrs. Baker, on the basis of that devised by Professor Huxley forthe use of his Practical Class at South Kensington, will be founddecidedly preferable. The framework of the instrument is solidlyconstructed in mahogany, all its surfaces being blackened, and is >»arranged as to give two uprights for the support of the stage andtwo oblique rests for the hands. Close to the summit of each of theseuprights is a groove into which the stage-plate slides ; and this mavbe either a square of moderately thick glass or a plate of ebonite,having a central perforation into which a disc of the same materialmay be fitted, so as to lie flush with its .surface, one of these beingn-adily substituted for the other, as nmy best suit the use to be. FIG. 202.—Zeisss lens-holder. made of it. The lens is carried on an arm working on a rackedstem, which is raised or lowered by a inilled-head pinion attached toa pillar at the further right-hand corner of the stage. The lengthof the rack is sufficient to allow the arm to be adjusted to anyfocal distance between 2 inches and J inch. But as the height ofthe pillar is not sufficient to allow the use of a lens of 3 inchesfocus (which is very useful for large dissections), the arm carryingthe lenses is made with a double bend, which, when its position isreversed, as in the dotted outline (which is readily done by unscrew-ing the milled head that attaches it to the top of the racked stem),gives the additional inch required. As in the Quekett micro-scope, a compound body may be easily fitted, if desired, to a separatearm capable of being pivoted on the same stem. The mirror frame 252 THE HISTORY AND DEVELOPMENT OF THE MICKOSCOPE i> fixed to tin- \\o
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
