86 



E. Miscellaneous Accessory Apparatus. 



Oculars for special purposes. 



No. 189. *ABBE'S Stereoscopic Ocular. Fig. 41. This apparatus is 



designed for stereoscopic as well as ordinary binocular observation of microscopical 

 objects with any desired magnification. (See CARL'S "Repertorium". vol. XVII. 

 1881, pp. 197224; also Journ. of the R. Micr. Soc. (2), vol. I, 1881, pp. 203-211; 

 E. ABBE, GesJAbhdl., vol. I, 1904, pp. 244272.) 



n. 



Fig. 60. ABBE'S Stereoscopic Ocular, Xo. 189. ('/'., Full Size.) 



The division of the pencil of rays emerging from the objective, with the 

 object of producing two separate images, is effected at the upper end of the 

 tube by partial reflection at a thin stratum of air between the two prisms a and b. 



