ZOOLOGY AND BOTANY^ MICROSCOPY, ETC. 525 



vapour is formed, wbicli disappears in a few minutes. When the 

 exhaustion is feeble the vapour is scarcely visible in diffused light, 

 but becomes very apparent when a beam of solar or electric light is 

 directed on it. 



A small box with glass walls, shown in position in fig. 107 and in 

 section in fig. 108, is placed on the stage of the Microscope, and to 

 it are attached two tubes fitted with stop-cocks. One of them com- 

 municates with a vessel partly filled with water for obtaining moist 

 air, the other with the receiver of an air-pump. The air in the glass 

 box can alternately be rarefied, and moist air allowed to enter at each 

 dilatation. By means of sunlight or electric light, the globules of 

 vapour formed can be examined ; but the author has not yet arrived 

 at any conclusion as to their constitution. 



Abbe, E. — Changing Eye-pieces without altering focus, &o. 



[Letter written in 1881 pointing out that to do this it is the anterior 

 principal focu3 of the eye-piece that must keep the same place in the 

 Microscope-tube. ] 



Micr. Bulletin (Queen's), III. (1886) pp. 9-10 (1 fig.). 

 American Society of Microscopists. — Working Session. 

 [" Schedule of Demonstrations," &c.] 



Proc. Amer. Soc. Alter., 8th Ann. Meeting, 1885, pp. 203-7. 

 Bulloch, W. H. — Magnification. 



[Answers to his questions, ante, p. 149.] 



Amer. Mon. Micr. Journ., "VII. (1886) p. 78. 

 BuRKiLL, T. J.— See Stratton, S. W. 

 C[ampbell], J. A. — Fine Adjustment. 



[1. Criticism of Mr. Mayall and Mr. Swift's views of his adjustment, ante, 

 p. 375. 2. Criticism of Anderson's fine adjustment, ante, p. 325.] 



Engl. Mech., XLIII. (_1886) p. 148. 

 Cole, A. H. — A new self-adjusting Frog-plate. \_Post.'\ 



Micr. Bulletin {Queen's), III. (1886) p. 11 (1 fig.). 

 Connor's (R.) Pen-and-ink drawings of objects viewed with the Microscope. 



[Vol. V. p. 1077.] Nature, XXXII. (1885) p. 633. 



Cox, J. D. — The Actinic and Visual Focus in Micro-photography with High 

 Powers 1 



[See Vol. V. (1885) p. 1070.] 



Proc. Amer. Soc. Micr., 8th Ann. Meeting, 1885, 

 pp. 29-32 (1 heliotype), and pp. 229-30. 

 Ceamek, C. — Ein neuer beweglicher Objecttisch. (A new movable stage.) 



IPost.'] Zeitschr. f. Wiss. Mikr., III. (1886) pp. 5-14 (2 figs.). 



CzAPSKi, S. — Ueber ein Mikrorefractometer. (On a Micro-refractometer.) 



[Description of Exner's, ante, p. 328, with critical remarks, and a suggested 

 improvement as regards the independent action of the screws on the 

 screen.] 



Zeitschr. f. Instrumentenk., VI. (1886) pp. 139-41 (2 figs.). 

 D'Aksonval, a. — Recherches de Calorimetrie. (Researches on Calorimetry.) 

 [Describes various forms of (1) apparatus for maintaining a constant 

 temperature, (2) regulators, (3) calorimeters.] 



Joum. Anat. et Physiol. {Robin), XXII. (1886) pp. 113-61 (26 figs.). 



Detmers, H. J. — The Numerical Aperture of an Objective in relation to its 



angle of aperture in air, water, and balsam. 



[Two tables : (1) Air angle, water angle, balsam angle, and N.A. for every 



2° of air angle from 1° and 2° to 180°. (2) Balsam angle, water angle, 



and N.A. for every 2° of balsam angle from 1° and 2° to 180°.] 



Proc. Amer. Soc. Micr., 8th Ann. Meeting, 1885, pp. 199-202. 



