. The microscope; a simple handbook. Microscopes. 56 THE MICROSCOPE Adjastable trough. Lire Fig. -No. 3413, Slip with Trough. convenient form mounted on a 3 X 1 slip; it has usually a space for water about 2 mm. thick. It is made with an upper glass either of thin microscope cover glass, about -25 mm. thick, or a thicker glass about 1 mm. thick. Fig. 54 shows a glass trough cemented together. This has dimensions of 1^ XlJ Xj inches, and is made of glass about 1 mm. thick. It is only suitable, owing to the thickness of the glass, for use with low powers. A very useful form of trough,
. The microscope; a simple handbook. Microscopes. 56 THE MICROSCOPE Adjastable trough. Lire Fig. -No. 3413, Slip with Trough. convenient form mounted on a 3 X 1 slip; it has usually a space for water about 2 mm. thick. It is made with an upper glass either of thin microscope cover glass, about -25 mm. thick, or a thicker glass about 1 mm. thick. Fig. 54 shows a glass trough cemented together. This has dimensions of 1^ XlJ Xj inches, and is made of glass about 1 mm. thick. It is only suitable, owing to the thickness of the glass, for use with low powers. A very useful form of trough, known as Beck's glass trough, is made of a 3 X 1 glass plate, into which arte fixed two screws and milled nuts, each holding a clamping plate. A half-circle of indiarubber made from an elastic band is laid on the 3x1 shp, and a glass cover plate of any re- quired thickness is placed on the top. The whole is clamped together by the milled nuts. As all the parts take to pieces, it can be readily cleaned, and cover glasses or separating bands of any thickness can be used. Separating bands of the very thinnest material, such as dental rubber, or even paper, can be used, so that the layer of material being examined is exceedingly thin. This is of great convenience when it is desirable to examine the specimens by dark-ground illumination or with high powers. It is a very convenient apphance also for the examination of aquatic specimens. These can be first arranged in position on the lower 3 X 1-inch slip within the area surrounded by the rubber band, the cover may then be placed in position and sufficient fluid dropped in. If a small circular cover glass be cemented in the centre of the 3 X 1-inch lower glass, a small drop of fluid can be confined to the centre of the field for ex- amination. It can be used with substage condensers or dark- ground illumiaators. A live box consists of a plate 3x1 inches, with an aperture in the centre of which is fixed a short brass tube carrying at
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectmicroscopes, bookyear
