. The microscope and its revelations. THE SUB-STAGE I87 stage ; the inner sliding plate is the essential addition to the usualracked slide, in the application of the new fine adjustment to thesub-stage. The range of motion is about ^th in.—the difference inradius between the smaller and larger ends of the steel cone. A very simple and practical device for the same purpose wassuggested by Mr. G. C. Karop, who knew that if the best possibleresolutions are required, the image of the flame given by the con-denser should be as accurately adjusted in the focal plane as theobject itself. This arrange
. The microscope and its revelations. THE SUB-STAGE I87 stage ; the inner sliding plate is the essential addition to the usualracked slide, in the application of the new fine adjustment to thesub-stage. The range of motion is about ^th in.—the difference inradius between the smaller and larger ends of the steel cone. A very simple and practical device for the same purpose wassuggested by Mr. G. C. Karop, who knew that if the best possibleresolutions are required, the image of the flame given by the con-denser should be as accurately adjusted in the focal plane as theobject itself. This arrangement of Mr. Karops, admirably suitedto the stands of Messrs. Swift and Son, was patented by that consists in the adaptation of their well-known climax or challenge fine adjustment to the slide carrying the sub-stage; butit is actuated by a milled head borne on the spindle to which is con-nected the coarse rack motion. As will be seen in fig. 149, it is alever actuating a stud fixed to the dovetailed slide which carries the. FIG. 148.—Fine adjustment to sub-stage. FIG. 149.—Karops fine adjustment for sub-Powell (1882). stage, made by Swift (1892). sub-stage. The extreme end of the lever is not acted upon by a finescrew, but there is a cylindrical pin one end of which engages thepoint of the lever, the other the face of the inner milled head ; themilled heads resemble the Turrell stage arrangement, but the innermilled head works on a screw on the stem of the outer milled head;when the inner milled head is turned it traverses the stem of theouter one, and pressure by the S-shaped spring in the fig. causes thestud to slowly raise or lower, as may be desired, the sub-stage whichcarries it. One complete turn of the inner head presses the sub-stagethe -^--th in. So that small fractions of this may be easily obtained,and it is an advantage that the milled heads of both movementsare so close to each other. Messrs. W. Watson and Sons have also devised a useful arrange-ment
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
