378 



INDEX. 



Lepisma saccharin urn, 133, 138. 



for demonstration 



of diffraction phe- 

 nomena, 231. 



Lenses Centering of the systems of, 79-84. 



,, cleaning and preservation of, 273. 



,, construction of, for elimination 



of Distortion and Curvature, 



72. 



,, difference and analogy between 

 an infinitely thin lens and 

 given systems of, 4-9. 

 ,, differential action of Aperture of, 



102-103. 

 ,, in connexion with Illumination, 



107, 110. 



,, testing the Centering of, 170-171. 

 , , Achromatic and Aplauatic, 54. 

 ,, Coddington's, 262. 

 ,, combination of, for determination 

 of Cardinal points, 57-62, 184- 

 188. 

 ,, condensing lens in Polarising 



Microscope, 304, 308. 

 Cylinder, 262-263. 

 of Eye-pieces, 35-48, 63-65. 

 ,, of Lantern Microscope, 267. 



of Objective, 27-34. 

 ,, of simple Microscope, 256-266. 

 See "Aberration," "Angle of 

 Aperture," "Eye-piece," "Focal 

 length," "Illumination." 

 Level, differences of, 254-255. 

 Liebcrkiihn Mirror, contrast to Illumina- 

 tion, 114. 



Light, Interference of direct with re- 

 flected, 240-243. 



,, Interference of refracted with re- 

 flected, 244. 

 , , Interference of refracted and direct, 



245. 



Interference lines caused by 

 withdrawal of source of, 239- 

 240. 

 technical directions with regard to 



Illumination, 268-271. 

 See "Diffraction," "Rays," "Re- 

 flexion," "Refraction." 

 Lister's method of determining Angle of 



Aperture, 173-174. 

 Lyrccna argv* t 133 ; 138. 



MAGNIFYING POWER, determination of, 

 36, 37, 178-181, 

 260. 

 , ,, for different ranges 



of sight, 37. 



,, selection of, 271. 



Measurement of microscopic objects, 288- 



296. 

 ,, Units of, compared, 294. 



Sec "Determination." 

 Membranes, bounded by one plane and 

 one undulating surface, 

 219-220. 



,, bounded by parallel un- 



dulated surfaces, 220-221. 

 ,, with small depressions or 



holes, 217, 219. 

 ,, drawing of, 300, 302. 



Merz's Spectral Eye-piece, 48. 

 Micrometer, determination of diameter of 



Field-of-view by, 181. 

 ,, determination of Focal length 



by, 181-183. 

 ,, determination of Magnifying 



power by, 179-181. 

 ,, determination of Objective 



amplification by, 181. 

 ,, Glass-, 288-291. 

 ,, Screw-, 291. 



,, Eye-piece Screw-, 291. 



Micromillimetre, proposed standard of 



unity, 293. 



Microscope, optical power of, 90-101. 

 ,, testing the, 126-188. 

 ,, component parts of, 27-50. 

 ,, base, 120. 



,, diaphragms, 119. 



,, focusing, 116. 



,, illuminating apparatus, 



118. 

 length and position of the 



tubes, 120-121. 

 ,, object stage, 117. 



,, placing the, 269. 



,, stands of modern opticians, 



122-125. 

 treatment, cleaning, &c., 



273. 



,, Lantern, 267. 

 ,, Multocular, 48-50. 

 ,, Polarising, 304-319; 354 (not*). 



