230 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



arrangement shown in fig. 25 may be used with diapositives. This 

 arrangement may, moreover, be used for the simultaneous projection of 

 two diapositives, the front part being fitted with a specially large illumi- 

 nating lens, which equally illuminates two adjacent diapositives adjust- 

 able in two mutually perpendicular directions. The diapositives may be 

 independently exchanged. 



Fig. 25. 



Application of Edinger's Drawing and Projection Apparatus to 

 Macroscopic Photography.* — P. Martin has devised a stand which very 

 much increases the usefulness of Edinger's apparatus.!. The stand is 

 manufactured by the firm of Leitz, and consists of a convenient frame- 

 work in which a camera can be placed and clamped at any angle. This 

 camera replaces the usual optical parts, and is capable, when adjusted at 

 a suitable distance, of projecting into the ordinary photographic part 

 images of very large objects. By this means the author has secured 

 photographs of the pelvis of a horse, or even of an entire horse carcass. 

 In the latter case the carcass was on the floor of a hall, and the frame 

 was conveniently arranged in a gallery over. The frame is mounted on 

 castors, and is therefore easily transferred to any desired spot, e.g. a 

 patient's bedside. AVith an horizontal adjustment, an object on a wall, 

 or vertical screen may be photographed. 



Ocular Micrometer with Interior Vernier. J — The firm of Nachet, 

 under the instruction of F. Vies, has manufactured an ocular micrometer 

 which is intended to possess a precision equal to that of the best divided 

 drum-micrometers, but with a less complicated mechanism. The read- 



* Zeitschr. wiss. Mikrosk., xxvi. (1909) pp. 219-22 (2 figs.), 

 t See this Journal, 1905, p. 650, and 1891, p. 811. 

 j C.R. Soc. Biol. Paris, lxvii. (1909) pp. 537-8. 



