234 



XVI. — On the Kaloscope. By Mr. W. H. Keys. 



Communicated by Mr. Geoege Moslet. 



Read February 5tlij 1861, 



One of the objections frequently advanced against the use 

 of the microscope is that it injures the eyes. All observers 

 are aware that they are constantly using a light which is 

 at least unpleasant from its brightness, if not positively 

 hurtful ; and attempts have long been made so to modify 

 the light that the observer may work on through a long 

 evening without pain or fatigue. 



It is hoped that the '^ kaloscope" will meet the wants of 

 all those who use the microscope frequently, enabling 

 them to pursue their investigations with the long-desired 

 comfort, and induce many persons to commence micro- 

 scopic studies who hitherto have been deterred through 

 fear that injury to the sight would be inevitable. 



The kaloscope consists of eight discs of coloured glass, 

 the discs having a uniform diameter of i\ inches. They 

 are mounted upon a stand of 12 inches in height, similar 

 to that used for a bull's eye condenser, but larger, and are 

 arranged in two sets of four glasses each, an upper set and 

 a lower set, each set being attached to an arm which can 

 be moved about in any direction; and as every separate 

 disc has its own independent motion, it will be obvious 

 that any angle of light may be obtained. The upper set 

 of glasses is fitted to a tube, which slides upon the upper 

 portion of the pillar of the instrument so as to allow of 



