488 



SUMMAEY OF CURRENT RESEARCHES RELATING TO 



(3) Illuminating- and other Apparatus. 



Giltsch's Drawing Stand.* — This simple apparatus (fig. 100) is 

 intended for use with a drawing-prism (camera lucida) or the large 

 Abbe drawing apparatus. Ordinary pocket-loups or spectacle-glasses 

 may be used. 



Fig. 100. 



The Apertometer and its Use.f — H. F. Angus argues against the 

 neglect of the apertometer and its supposed limited range of usefulness. 

 He also points out that the objection on the score of expense vanishes if 

 either of the two following simple forms be used, and that, except for 

 immersion lenses, these simple instruments are amply sufficient. 



* Zeiss' Catalogue, 1902, No 116, fig. 50, p. 91. 



t Journ. Quek. Micr. Club, viii. (1902) pp. 209-15 (1 fig.). 



