ARTIFICIAL LIGHT. 191 



of the cover, or perhaps v/ith the aid of the bit of blue 

 glass in eye-piece. For work at night we employ at 

 times all the lamps we have described. Should the 

 routine examinations be prolonged into the evening, we 

 use the German student's lamp for preliminary work, 

 the same as we use diffused daylight in the day time. 

 But should the higher amplifications become necessary, 

 we bring the mechanical or the little hand-lamp into 

 play. The German student's will still do service in the 

 lighting up generally of the work-table at intervals. 

 For the showing of such objects as the Nos. 18, 19, and 

 20 of the Moller plate by lamplight, of course the little 

 hand-lamp, or the lower model mechanical is impera- 

 tively employed, especially when the Wenham " reflex " 

 illuminator is selected. 



There remains yet another method of sunlight illumina- 

 tion which will be found useful at times. I refer to the 

 use of the* 'reflex" illuminator with direct sun-light. 

 In this case the solar beam can be received through a 

 closed window (quite a boon in the winter season) and 

 reflected from the plane mirror. This illumination is 

 only suitable for work with wide apertures, and ever 

 the most minute objects, and the mount must be free 

 from surrounding objects of a coarse character, else, 

 from the extremely oblique character of the illumina- 

 tion these stronger and coarser objects will project their 

 strong shadows across the field, causing nothing but 

 contusion and chaos. With the genuine form of the 

 Wenham " reflex " an epithelial scale would hardly be 

 recognized were there several in the field. The princi- 



