Quarterly journal of microscopical science . 1 in. in diameter, in its centre; c is a trough of thesame material, l^in. in length, 1 in. in breadth, and ^ indepth, placed on the plate, sloping diagonally from thecentral opening in the plate to one corner; it is partly coveredin, as shown in the drawing ; D D is a little square glassstage, raised ^ in. from the plate over the opening, and in aline with the trough ; e is an inclined plane, connecting thesurface of the glass stage with the floor of the trough ; r isa small india-rubber tube, conveying water to the troughfrom a tap; g is a second
Quarterly journal of microscopical science . 1 in. in diameter, in its centre; c is a trough of thesame material, l^in. in length, 1 in. in breadth, and ^ indepth, placed on the plate, sloping diagonally from thecentral opening in the plate to one corner; it is partly coveredin, as shown in the drawing ; D D is a little square glassstage, raised ^ in. from the plate over the opening, and in aline with the trough ; e is an inclined plane, connecting thesurface of the glass stage with the floor of the trough ; r isa small india-rubber tube, conveying water to the troughfrom a tap; g is a second tube, conveying the water away,and placed at such a level that the trough is always nearlyfull, but cannot overflow : h h is a loop of silk cord, whichpasses through two little holes, K K, in the plate. The fish is placed in the trough (as shown in dotted out-line), with its tail on the glass stage. The upper part of the 239 loop of thread marked h is passed over the tail, and by pull-ing its lower end h, is drawn down over the narrow part. Outline Sketch of Tish-Trough on the Stage of the Microscope. of the tail; by this means the tail is held still: l l are twosmall springs, which press gently on the glass stage; the tailis now stretched to its natural width, and each extreme edgeplaced under one of these springs. It is well to have a tap on the supply pipe; one on thewaste-pipe is also useful, as thereby an unjjleasant bubblingmay be prevented. If the trough is in order, not a drop ofwater escapes. The microscope should be incKned at anangle of about 45°. A gentle stream of water being kept circulating, the fishmay be left in this position some hours without apparentinjury. Eight hours is perhaps the maximum. In a suitable fish, free fiom parasites, the tail membranesare as clear as glass. They contain a close capillary thinness and transparency are such as to allow of theuse of dry objectives as high as the ^V^h. In this case a filmof talc answers better than a gl
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondo, bookyear1870
