768 SEC. 18. BIOLOGl'. 



3559. Large Microscope, suitable for any research, with 

 rotating stage, and joint for inclining the body of the microscope. 



JR. Wasserlein, Berlin. 



3560. Small Student's Microscope. 



R. Wasserlein, Berlin. 



3561. Microscope No. 1, combined with a photographic 

 apparatus and accessories. Seibert $ Krafft, Wetzlar. 



This apparatus can be connected with every simple microscope, which, for 

 this purpose, is placed perpendicularly under the box in front of the appa- 

 ratus, after which, in order to exclude unsuitable light, the cloth-bag, fitting 

 tightly by means of a gutta percha ring, is pulled over the tube. The adjust- 

 ment of the picture is effected by means of the glass-plate contained in the 

 box, which is provided with squares and the ocular -like microscope. The 

 lines of the glass-plate must be placed downwards. The microscope is placed 

 on the glass plate, and regulated by the tipper lens in such a manner that the 

 lines can be seen plainly ; thereupon the picture is inserted, the microscope 

 being used as ocular. In this manner the picture is sure to lie exactly on the 

 lower surface of the glass-plate ; consequently also on the prepared plate to 

 be inserted afterwards. By applying the illuminating apparatus the plane- 

 mirror of the microscope should be used, the arrangement of which is easily 

 understood. The achromatic condenser, accompanying the apparatus, con- 

 sists of three achromatic lenses, and fits in microscope No. 3 in the 

 Exhibition. 



3562. Microscope No. 3. Seibert fy Krafft, Wetzlar. 



3563. Microscope No. 5. Seibert fy Kraff't, Wetzlar. 



3564. Microscope No. 7. Seibert $ Kraftt, Wetzlar. 



3565. Complete Microscope, with Abbe's illuminating 

 apparatus, magnifies from 20 to 1100 diameters. 



F. Schmidt and Haensch, Berlin. 



3566. Microscope (specially adapted for mineralogical re- 

 search), with polarisation apparatus. Ernst Leitz, Wetzlar. 



Height of the instrument, 1 foot 3 inches. 



There is an arrangement for turning the tube round the optical axis, together 

 with the upper round stage, which is prepared (after the design and drawing 

 of Professor Mohl of Cassel) with a graduated rim. 



The under-stage carries the vernier, and is provided with a circular 

 diaphragm, which, together with the polariser, is furnished with a convex lens. 



The coarse adjustment is done by a rack and pinion, and the fine adjust- 

 ment by a micrometer screw ; with draw-tube, and plane and concave mirror 

 with vertical and horizontal movement. An eye-piece micrometer, the cross 

 lines of which can be easily used for estimating the angle of dichroisin, and 

 angle measurement, by holding the eye-piece fast and turning the stage on 

 which the object lies. A revolving fitting for holding five objectives. 

 Analyser for fixing to the eye-piece, with a graduated circle. 



A calcspar plate placed between the eye-piece and the analyser serves for 

 the stauroscopic examination of crystals ; magnifying powers 60 to 2,800 

 diameter. 



