460 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



the carrier is in its initial position the slide is placed horizontally in a 

 sort of recess prepared for it at the top of the drum, which is then 

 rotated backwards through 90°, so as to bring the slide in front of the 

 condensing lens : it is now in the proper position for projection. A 

 second slide is now put in at the top and the drum rotated through a 

 further 90°. The first slide is now horizontally at the bottom of the 

 drum, and automatically falls out on to a soft surface suitable for its 

 reception ; the second slide has now come into the projection position. 

 The fourth side of the drum, viz. that opposite the slide displayed, is 

 always clear and therefore offers no obstacle to the free passage of the 

 light. A suitable arrangement of bars ensures that the apparatus shall 

 stop accurately in the proper positions. The foot has been designed 

 for attachment to the prismatic bar of an optical bench, but could, of 

 course, be modified for other applications. 



Bebgmann — Das Trichinoskop. Zeitschr. Fleisch u. Milchyg., xiii. (1903) p. 111. 



Dowdy, S. E. — Attachable Object-finder. 



English Afec/itmc, lxxix. (1904) p. 410(1 fig.) 



Hitohcock, E. — The Ideal Projecting Microscope. 



Journ. New York. Micr. Soc, Animal of 1902, pp. 19-23. 



Ites, F. E. — Ein neues Binocularmikroskop. 



Central zeitg. Opt. u. Median., xxiv. (1903) p. 38. 



„ „ Franzbsische Mikroskop. Op. cit., xxiii. (1902) p. 98' 



Kohler, A. — Das Zeiss 'sche Trichinoskop. 



Zeitschr. Fleisch u. Milchyg.,xiii. (1903) p. 107. 



Lbitz, E. — Ein nenes Mikroskopstativ und seine feine Einstellung. 



Zeitschr. Imtrumentenlc, xxiii. (1903) p. 79. 



Fio. 68. 



(2) Eye-pieces and Objectives. 



Zeiss' Compound Lens with Iris Diaphragm.* 

 This is shown, one-third full size, in fig. 68. The 

 lens having an aperture of about 6 cm. with a focal 

 length of about 12*5 cm., is secured in a ring, which 

 carries an iris diaghragm of aperture 3 to 6 cm. 

 The desired aperture is attained by means of the 

 lever G-. The ring hangs in a semi-circular sleeve, 

 and is rotated by means of the knob K, about a 

 horizontal axis capable of being clamped by the 

 screw Sr. The sleeve is screwed on to a rod S£, 

 which a clamping screw S r l grips inside a rider or 

 cylindrical foot. The lens is primarily useful for 

 illumination in photomicrography, in case light 

 sources with enlarged surface, such as incandescent 

 gas and petroleum light, are used ; it can be applied 

 to the upright or sloping Microscope. With trans- 

 parent light it must be used in conjunction with a 

 condenser. With reflected light it can be used either 

 alone or with a vertical illuminator. The instru- 

 ment can be also used for ordinary microscopic work. 



Deutsche Mecbaniker-Zeitung, No. 3 (Feb. 1, 1904) p. 28 (1 fig.). 



