ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



389 



wick'used edge-on will fully expose a medium orthochromatic plate in 

 from ono to two minutes, usiny: a l/12th apochromatic objective and 

 Zeiss' No. 4 projection ocular. For line low-power work, the oil-lamp 

 with a circular wick is indispensable. 



Fig. 98 



---■=» 



Hubbard, J. C. — Colour Screens as applied to Photomicrography. 

 • 1 Journ. Boston Soc. Med. Sci., III. (1899) No. 11, p. 297. 



Martens, Dr. F. F. — Einige neue photometrische Apparate. (Some new Photo- 

 metric Apparatus.) 



[The instrument is on the spectroscope principle, but by means of a mirror the 

 absorption band is brought immediately under the fixed band, and so more 

 perfect comparison is obtained.] 



Zeit.f. angew. Mikr., March 1900, pp. 338-40 (1 fig.). 

 Hoster, G. — Le applicazioni della fotographia nella scienza. (The applications of 

 Photography iu Science.) 



Cougr. Futogr. Ilal. Firenze, Atti ii. (1899) SA., 26 pp. 



