73. =The Binocular Preparation Microscope=, after the model of Eilhard Schulze permits the convenient use of both eyes in dissecting small anatomical and botanical preparations. It consists of two Brücke lenses, adjusted to an accurate focus. Both tubes are moveable on a joint and are adjustable to various distances between the observers eyes. The distance of the eye from the preparation is about 250 millimetres; the field of vision is large and flat; the magnification, four diameters; lenses are adjustable to either vertical or horizontal position and may be raised and lowered on the vertical support, thumb-screws fixing them in the desired position. A rack and pinion serves as fine adjustment =24.--= [Illustration: Greenough's Binocular Microscope.] 74. =Greenough's Stereoscopic Binocular Microscope.= Two microscope tubes are so arranged as to bring the same object into focus in the axis of each tube, the tubes being set at an angle to each other for this purpose. The stand is provided with rack and pinion adjustment and both draw-tubes are also regulated by a rack and pinion arrangement, so that they may be adapted to the correct distance of the observers eyes. By interposition of prisms the image is rendered erect. Magnification, 20 diam. Price =80.--= 74a. =Corneal-Microscope=, is designed for the examination of the interior of the eye. =Prismtube= No. 49 with eye-piece =16.--= =Objective= of low power permitting 2 degrees of magnification =6.--= =Stand= on heavy base, with rack and pinion adjustment etc. =8.--= ------- =30.--= =Apparatus for Blood Examinations.= [Illustration: Micro-Spectroscope.]