676 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



of corroctiou collar of an objective. The nose-piece consists of 

 two tubes, tbe inner one being pressed upwards by a spiral spring 

 encircling it ; it is provided with two pins which travel in slots in 

 the outer tubo ; a screw collar on the latter works against the pins, 

 and thus controls the motion upwards or downwards of the inner tube. 



Nachet's Corneal Microscope. — M. Nachet sends us fig. 118, 

 showing his form of Corneal Microscope, which, unlike that by 

 Schieck described Vol. IV. (1884) p. 954, has binocular body-tubes. 



The body-tubes E E ai*c attached to the standard F, which consists 

 of three tubes sliding in oue another and intended to be clamped to the 

 table. The body-tubes can be inclined on a hinge joint. There is a 

 coarse adjustment at G. The leather-covered pads C C form a rest for 



Pig. 118. 



the forehead of the person under observation, and B for his chin. 

 They can be adjusted to different lengths. The little ball H is used 

 as an object to be followed by the eye of the patient, so as to present 

 different parts of the cornea to observation. D is a bull's-eye con- 

 denser. The screws on the standard are for adjusting the two arms 

 in any desired position and for clamping the sliding tubes of the 

 standard at any given point of extension. 



The instrument is also adapted for examining aquaria, and surfaces 

 of all kinds, the skin, &c. 



Use of the Microscope in the Mechanical Arts. *— Mr. G. M. 

 Hopkins indicates the many uses which may be made of the Micro- 

 scope in workshops, not only for making fine measurements and 



* Central-Ztg. f. Optik u. Mecli., vi. (1885) pp. 270-2 (10 figs.). 



