No. 51 057. 



Projection Microscopes. 



183 



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51 047. 1:5. 



51 048. 1 : 5. 



51 058, 50 796, 51 060 a, b, k. 1 : 9. 



an image on to the projection screen. The bottom board can be adjusted to various heights, in order s. d. 

 <J to equalise the thickness of the object - 



51.047. Projection Microscope for Projecting Microscopical Preparations, Figure, with 



j rack motion, but excluding objective 2.10.0 



^ The microscope .can also be fitted with 2 bright tourmaline discs to enable polarisation pheno- 



cs mena to be demonstrated: see No. 51.056. 



51.048. --The preceding, with Micrometer Adjustment for high magnifications, 

 Figure " 4. 0. 



Objectives for above, achromatic. 



List Xo. 51,049 51,050 51,051 51,052 51,053 

 Hartnack Objective Xo. 23579 



0. 18. 1. 7. 1. 13. 1. 18. 3. 6. 



51.054. Revolving Collar for 2 Objectives, for rapidly changing the magnification .... 0.16.0 



51.055. Revolving Collar for 3 Objectives 1. 2. 



51.056. 2 clear Tourmalines, in mount, to enable the microscope to be used simultaneously 



as a polarisation apparatus 2. 5. 



One of the tourmalines is placed under the object stage and the other in the tube of Micro- 

 scope No. 51,047. If the device is intended for use with No. 51,048, this fact should be mentioned 

 when ordering as the mounts in this case must be constructed differently. 



51.057. Projection Microscope (Lehmann's). cf. Fig. 51,058. for observing objectively the 

 formation, growth, etc. of solid and liquid crystals (Frick, Phys. T. I., 1, Fig. 437), 

 with large water trough fitted with draining cock and cooling coil, heating and cooling 

 device (which can be regulated), 2 holders for the nicol mounts (which can be pushed 

 out), rotatory object stage, for setting on the optical bench of the projection lanterns, 

 megadiascope, etc. Price, in box, without objectives or nicols 20.15.0 



Among the extensive literature on the subject of the observation of solid, flowing, liquid and 

 apparently five crystals, special mention may be made of the following: 0. Lehmann, ,,Die scheinbar 

 lebenden Kristalle"', Anleitung zur Demonstration, Esslingen, 1907. 



Cf. also the water-colled Projection Microscope, No. 9531, listed on p. 1222. 



Cl. 275, 4506, 

 275'. 



