= go 



The positions "right" and "left" being reversed in consequence of the single 

 reflection at 83, and as this would cause inconvenience in certain cases we construct a 

 second form of the instrument, Xo. 11)7, in which the objectionable 

 reversal is obviated by the addition of another prism. 



No. 198. The Capillary Rotator, Fig. 44, serves to rotate about a hori- 

 zontal axis small objects which may be contained in a capillary tube. The in- 

 strument is so arranged that the capillary tubes may be rotated within a chamber 

 fitted with cedar-wood oil, so as to obviate the disturbing effects of irregular 

 refraction and of reflection caused by the walls of the tubes. 



. 44. Capillary Rotator. No. 198. ( : '/ 6 Full Size.) 



While the Prism Rotator is primarily designed for use on Binocular Stand X a . 

 but may also be used with other stands having a stage opening )>;> mm (l'/ 3 in.) 

 in diameter, the Capillary Rotator, because it may be held by means of clips like 

 any ordinary object-carrier, is adapted for all stands alike. 



Regarding the details of the construction of the two instruments see Zeit- 

 schrift f. wiss. Mikrosk., vol. XIV, 1897, pp. 304 312. 



flrtificial Illuminating appliances for the Microscope. 



Lamplight, if properly regulated, may almost completely replace good 

 daylight. 



It is advisable to interpose between the source of light and the mirror of 

 the microscope a spherical glass flask filled with water (such as is sometimes 

 used by engravers) or, better still, a simple collective lens, so as to project a 

 sufficiently large image of the source of light upon the iris-opening or upon 

 the mirror. 



No. 

 198 



GREENOUGH's Capillary Rotator 



Marks Codeivord 

 50. Pcrdcras 



