474 



SUMMARY OF CURLENT RESEARCHES RELATI^CG TO 



interest, and we have therefore made a limited selection (hardly more than 

 a quarter 1) which may serve to give a few hints to any who desire to contrive 

 any variations on the forms hitherto iu use. 



I. Of those which have now a purely historical interest only, are Prof, 

 J. GerJach's* (fig. 118) and MoUer and Emmerich's J (fig. 119). These 

 require no description. 



Fir,. IIP. 

 Fig. 118 



Nearly the same remarks apply to the complicated arrangements of 

 Dr. B. BenecJce t (figs. 120 and 121) intended for use with the highest 

 powers. 



Fig. 120 shows the camera as mounted on a stand for use with direct 

 sunlight and without any mirror. The stand is so contrived that when once 



* 'Die Photographie al3 Hulfsmittel mikroskopischer Forechung,' 1863, viu. and 

 86 pp., 9 figs, and 4 pis. of photomicrosrraphs. 



t Cf. Dippel's ' Das Mikroakop,' 1867. p. 211-3 (2 figs.). 



I 'Die Fhotograpliie als Hilfsmittel mikroskopischer Forsehung (nach dera 

 Franzosisch von Dr. A. Moitessier).' 1S6S, xiv. and 265 pp., 88 figs, and 2 pis. of photo- 

 micrographs. 



