and Laboratory Methods 



1999 



chromatic, that form the 

 visual image. If the mi- 

 croscope image is focused 

 by a short-sighted or far- 

 sighted eye, the focus 

 should be obtained 

 through a glass which 

 corrects the eye for paral- 

 lel rays, otherwise slight 

 readjustment of the fo- 

 cus of the microscope 

 may be necessary to make 

 the image perfectly sharp 

 on the ground glass of 

 the camera. 



The camera is mount- 

 ed on a frame, supplied 

 with rack and pinion, so 

 that it may slide longi- 

 tudinally to and from the 

 microscope in alignment 

 with its optical axis. The 

 two side arms of this 

 frame are pivoted to 

 brackets, securely attached to th 

 that microscope and camera may 



Fig. 



4. — Antenna of Fly. B. & L. % objective: 

 Huyghenian eye-piece. 



Series I 



e baseboard of the apparatus in such manner 

 be tilted to any desired inclination, from hori- 

 zontal to vertical (Fig. 1). 

 The apparatus appears 

 to be far less sensitive to 

 vibrations when used at an 

 angle of 45° than when 

 either horizontal or vertical. 

 Although this simple ap- 

 paratus will not produce 

 photographs of large size, 

 such as can be made with 

 projection eyepieces and 

 very long cameras, nor in- 

 clude wide angles of view 

 in low powers, such as may 

 be obtained with Planar 

 lenses without eye-pieces; 

 photo-micrographs made 

 with it, ranging from com- 

 paratively low amplification 



Fig. 5. — Coscinodiscus asteromphalus, x 2000. 



up to 1,500 diameters, are 



