. The microscope and its revelations. me may lack some most important elementsas .-( linished instrument. But this is an instrument of the highestorder as such, and at the same time a very fine specimen of highlyfinished brass work. A note must be made beforeleaving this microscope upon thesize of the tubes in the body andthe sub-stage. Powell and Lealand were theonly makers whose gauge oftubing had a raison detre ; thesize of the tube was such that itwould take in a binocular body aIluvidieiiian 2-inch eye-piece, having the largest field-glass pos-sible. The size of this field-glassdepends on
. The microscope and its revelations. me may lack some most important elementsas .-( linished instrument. But this is an instrument of the highestorder as such, and at the same time a very fine specimen of highlyfinished brass work. A note must be made beforeleaving this microscope upon thesize of the tubes in the body andthe sub-stage. Powell and Lealand were theonly makers whose gauge oftubing had a raison detre ; thesize of the tube was such that itwould take in a binocular body aIluvidieiiian 2-inch eye-piece, having the largest field-glass pos-sible. The size of this field-glassdepends on two factors. 1. The distance between thecentres of the eyes. -. The mechanical tube-length. In order that the binocularmay suit persons with narrowcentres to their eyes, the dis-tance between them should not be greater than :H inches. Themechanical tube-length is s:i inches for the standard tube. When(lie eye-pieces were -home in their places in the tubes they justtouched each other, the inner sides of t he binocular tubes being cut. FIG. 158.—Powell and Lealands sub stage with line . incut i 1882). away; so under the a hove conditions a larger fieh obtained is simply impossible. The size of themines Ihe size of the eye piece, and that was made than diameter of t he h,l\ t ube. \\i-ely these makers made the tube of the tubing Used as field-glass to is thusdeter-fix the same size, so as to have one gau^e of sub-stage the Thisa condenser, thus throughout. allows a Kellner Or other e\e piece to b, !•<• liHino- the number of adapters. l-alely this linn ha\e altered their snh-staye tube to a yaugetnmended by the Royal M irmscopical Society. This involves lapter where the sub-stage apparatus was adapted to the oldwln an eye piece is used as a condenser; as the size islarge for a binocular. - iu its completes) form as left by Andrew Ross, T. ROSSS MICROSCOPE 197 except specially ordered is never made by this firm, but for itsqualities and historical relations it is of
Size: 1490px × 1678px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
