110 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
sizes, by which the size of the picture may be regulated. Accurate 
tocusing is effected by means of a simple leus which moves over the 
Fig. 8. 
image-plate. The plate-holders are made for plates of the sizes, 9 by 
12 cm. (3J by 4f in.) and 13 by 18 cm. (5 by 7 in.). 
On Instantaneous Photomicrography.* — Herr G. Marktanner- 
Turneretscher remarks that three methods of making instantaneous 
photographs of microscopic objects have been proposed besides the 
primitive process of simply placing an instantaneous shutter between 
the source of light and the object. 
In the first method, which requires the most intense illumination, 
the light from the object is reflected by a suitable arrangement of prisms 
* American Annual of Photography, 1894, pp. 245-8 (1 fig.). 
