35 



hypotenuse surface of ;i reflecting prism, which covers one half of the aperture 

 of the objective, and are thence totally reflected through the objective and con- 

 centrated upon the object 



Vig. i:{. 

 Vertical Illiiiiiinalor No. 42. 



A: view of same (partly sectional) 



attached to the lower tube and the 



objective C the latter in short 



" mount; p: reflecting prism. B: plan 



view ; K: milled knob for revolving 



the prism. 



(Full Size.) 



As it is of importance for the efficient working of the apparatus that the upper 

 lens of the objective should be as close to the prism as possible, most objectives intended 

 for work with a vertical illuminator should be fitted in special mounts. 



Preparations under a cover -glass are not suitable for examination with the apparatus, 

 unless homogeneous immersion systems are being employed; again, the higher powers 

 of the Apochromats, 8 mm and upwards, and the Achromats, D and upwards, with the 

 exception of the homogeneous immersion systems, must therefore be specially corrected 

 for investigation of uncovered objects. 



It is furthermore of great advantage to reduce the diameter of the image of the 

 source of light so that the illuminated portion of the object may not be greater than 

 the area of the visual field of the objective used. The: readiest means to attain this 

 object is by placing the Collective Lens with Iris-Diaphragm No. 201 in the most favour- 

 able position before the microscope. See Directions for Use of the Vertical Illuminator. 



No. 48. An illuminating appliance employing an incandescent lamp, by the 

 aid of which intense light may be at once directed upon any particular point to 

 be examined, is provided for use with Stand X, known under the designation 

 of the Corneal Microscope. Similar appliances are also applicable to our 

 other binocular stands (see p. 63). 



Illimiinatiim appliance by means of small incandescent 



lamps for Stand X, including 3 reserve incandescent lamps 



Marks Codeivord 

 '{<>. Puraiiffon 



t, Sena. 



