INDEX 



ABB 



Abbe (Prof.), on amplifying power of lens, 

 26 ; on homogeneous immersion, 28 ; 

 on .improvement of optical glass, 32 ; 

 on classification of eye-pieces, 34 ; on ! 

 principle of microscopic vision, 43, 44, 

 45 ; on definition of aperture, 44 ; on 

 aperture, 48 note ; on radiation, 57 ; 

 on angle of aperture, 60, 61, 62 ; on 

 diffraction, 63-75 ; on ' intercostal 

 points,' 73 ; on ' penetration,' 82 ; on 

 over-amplification, 90; on stereoscopic 

 vision, 90, 94 ; on ' aplaiiatic system,' 

 94 ; on orthoscopic effect, 95 ; on Rams- 

 den's circles, 106 ; on solid cones of 

 light, 418 



his stereoscopic eye-piece, 102 ; camera 

 lucida, 281-284 ; apertometer, 307, 

 390-396; chromatic condenser, 308- 

 309 ; achromatic condenser, 311-312, 

 385 ; condenser, iris-diaphragm fitted 

 to, 312; diffraction theory and homo- 

 geneous immersion, 364 ; compensa- 

 tion eye-piece, 378 ; method of testing 

 object-glasses, 384-387; test plate, 

 387-390 : experiments in diffraction 

 phenomena, 434 



Aberration, 19 ; positive, 21, 360 note ; 

 negative, 21, 27, 360 note; chromatic, 

 81 ; spherical, 31, 301, 306, 388 ; errors 

 of spherical and chromatic, corrected 

 by Ross, 857 



Abies balsamea, 443 



Abiogenesis, 761 



Abraham's prism, 401 



Absorption or dioptrical image, 64 



and diffraction images due to diffrac- 

 tion, 65 note 



~ of light rays, Angstrom's law, 323 



bands, 323-327 

 Abstriction of spores, 633 

 Acalephce, sexual zob'ids of polypes, 862 ; 



relationship to hydroids, 872 ; develop- 

 ment of, 874 ; medusan phase of, 877 



Acantliometra xiphicantha, 850 ; echi- 

 noides, 852 



Acanthometrina, 846, 852 ; central cap- 

 sule of, 852 



Acarina, eggs of, 1004-1006 ; anatomy of, 



ACT 



1009-1012 ; larvae of, 1009 ; nymph of, 

 1009; integument of, 1010; legs of, 

 1010; eyes of, 1011; classification of, 

 1012 



Accommodation, of the eye, 88 ; depth, 89 

 Acetabulama, 563 ; pileus of, 563 

 Acetic acid, as a test for nuclei, 517 

 Acheta, 987 



campestris, eggs of, 1005 



Achlya, zoospores of, 564 ; obspores of, 

 565 ; zobsporanges of, 640 



prolifera, 563 and note, 563 

 Achnanthece, characters of, 615 

 Achnanthes, frustules of, 588, 615 ; stipe 



of, 588, 615 ; ' stauros ' of, 616 ; struc- 

 ture of frustule, 615 



Achnanthes longipes, 615 



Achromatic, comparison of, with chro- 

 matic and apochromatic lenses, 368 



condenser, Abbe's, 260, 308-312, 314 ; 

 Powell and Lealand's, 301, 311 ; for ob- 

 servation of pycnogonids, 959 



doublet, Fraunhofer's, 148 ; meniscus, 

 876 



lenses, Charles's, 148 ; Marzoli's, 353 ; 

 Selligue's, 354 



objectives, 19, 32 ; Tully's, 354 ; Wen- 

 ham's, 361, 862; cover slips for use 

 with, 439 



oil condenser, Powell and Lealand's,. 

 310, 311 



Achromatism, 17, 19, 150 ; in photo- 

 micrography, 34 ; rise of, 147 ; in- 

 augurated, 365 ; imperfect, causing 

 yellowness, 417 



Acineta, 783 



' Acinetiform young ' of Ciliata, 782 note 



Acinetina, 783 ; food of, 783 



' Acorn ' monad, 759 



' Acorn-shells,' 967 



Actinia, reproduction from fragments > 

 863 



Candida, thread-cells of, 879 



crassicornis, thread-cells of, 879 

 Actinocyclus, 588, 610, 620 

 Actinomma inerme, 850, 851 

 Actinophrys, 846 



form of Microgromia, 736 



sol, 737-742 

 Actinoptychus, 588, 610, 611 



4 D 



