. The microscope and its revelations. FIG. 277.—The English form of bullV 330 ACCESSOKY APPARATUS designate it as we have done). It is a plano-convex lens of shortfocus, two or three inches in diameter, mounted upon a separatest;ind in such a manner as to permit of its being placed in a greatvariety of positions. The mounting shown in fig. 277 is the usualadopted in England; the frame which carries the lens is borneat the bottom upon a swivel joint, which allows it to be turned inanv azimuth ; whilst it may be inclined at any angle to the horizon,liv the revolution of the horizontal tube to wh
. The microscope and its revelations. FIG. 277.—The English form of bullV 330 ACCESSOKY APPARATUS designate it as we have done). It is a plano-convex lens of shortfocus, two or three inches in diameter, mounted upon a separatest;ind in such a manner as to permit of its being placed in a greatvariety of positions. The mounting shown in fig. 277 is the usualadopted in England; the frame which carries the lens is borneat the bottom upon a swivel joint, which allows it to be turned inanv azimuth ; whilst it may be inclined at any angle to the horizon,liv the revolution of the horizontal tube to which it is attached,around the other horizontal tube which projects from the stem. Bythe sliding of one of these tubes within the other, again, the hori-/.outal arm may be lengthened or shortened; the lens may besecured in any position (as its weight is apt to drag it down when. FIG. 277.\. it is inclined, unless the tubes be made to work, the one into theother, more >tillly than is convenient) by means of a Tighteningcollar milled at its edges: and finally The horizontal arm isattached to a spring socket which slides up and down upon a verticalstem. \ -ond form of the bulls-eye is made by and is illustratedl!77\. All the required movements are provided lor, but in a,different way; the clamping screws are by means of usual milledheads. The plane side of the bulls-eye should be turned towards theobject. Some microscopist s like to have their bulls-eye attached tosome ie microscope; but if this is done, care must betaken ittach it boa li\ed part of t he microscope, ami not to either the THE USE OF THE BULLS-EYE 331 mechanical stage or to the body, as is so often done. If it is fixedto the mechanical stage, when the object is moved the light willrequire to be readjusted, to say nothing of the probable injury tothe stage by the weight of the bulls-
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
