100 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



bellows, condenser of 160 mm. diameter and diaphragm, objective of 

 200 mm. focns for diapositives up to t) by 12 cm., are represented in 

 figs. 18, 19. 



Pig. 19. 



Stereoscopic Photo-micrographic Attachment for Monocular 

 Microscopes.* — This apparatus (fig. 2(i), designed by Professor H. 

 Jackson, allows of beautiful stereoscopic photographs to be taken with 

 low powers such as 3 in., 2 in., and 1 in. objectives. It consists of a 

 short fitting into which the object-glass is screwed, and contains an iris- 

 diaphragm below which a slot is cut. Into the 

 slot a strip of blackened metal slides, and this 

 covers one half of the posterior combination of 

 the objective. If, with the edge of the metal slide 

 vertical, a negative be taken through one half of 

 the lens, and another be taken after removing the 

 slide and reinserting it so as to cover the other 

 half of the back combination of the objective, these 

 these two negatives will give prints yielding a 

 stereoscopic effect such as is seen in a binocular Microscope. The iris- 

 diaphragm is useful for lengthening the apparent depth of focus of the 

 objective. Made by Swift and Son. 



A New Slideholder.f — Under the name of GleitHneal, C. Detto has 

 designed a new form of slideholder. Hi« attention was drawn to the 

 matter by the difficulties of manipulating slides placed vertically in a 

 projection Microscope. His apparatus consists essentially of a rotatory 

 metal fo^k fastened on the rim of a circular stage of a Microscope. One 



* Swift & Son's Catalogue, pp. 66, fig. 102. 



t Zeitschr. wiss. Mikrosk., xxiii. (1906) pp. 301 -7 (2 figs.). 



Fig. 20. 



