ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 321 



Bray, A., and E. Sulzbeegek. — La Photomicrographie. Kapport sur la Con- 

 ference pratique de M. le Prof. Francotte. (Photomicrography. Eeport on the 

 practical demonstration of Prof Francotte.) 



BulL Soc. Belg. Micr., XIII. (1887) pp. 59-69. 

 Fbancotte, P.^ — Resume d'une Conference sur la MicrophotograpMe appliquee a 

 I'Mstologie, I'anatomie comparee et I'emhryologie. (Summary of a lecture on photo- 

 micrography applied to histology, comparative anatomy, and embryology.) 



Bull. Soc. Belg. Micr., XJII. (1886) pp. 24-56 (5 figs.). 

 Garkison, F. L.— See infra, j8 (2). 



Heurck, H. tan. — Application du petit appareil photographique aux Microscopes 

 continentaux. (Application of the small photographic apparatus to Continental 

 Microscopes.) Bull. Soc. Belg. Micr., XIII. (1887) pp. 82-3. 



Israel, O. — Ueber Mikrophotographie mit starken Objectivsystemen. (On photo- 

 micrography with high powers.) 



Arch. f. pathol. Anat. u. Physiol., CVI. (1886) pp. 502-14. 

 Merger, A. C. — The Indebtedness of Photography to Microscopy. 



Rep. from Phot. Times Almanac, New York, 1887, 7 pp. 

 Stenglein, M., and Sohultz-Hencke. — Anleitung zur AusfiLhrung mikrophoto- 

 graphischer Arbeiten. (Introduction to practical photomicrography.) 



viii. and 131 pp., 5 figs, and 2 phot., 8vo, Berlin, 1887. 

 SulzbebgeEj R. — See Bray, A. 



(6) Microscopical Optics and Manipulation. 



EwELL, M. D. — Micrometric Measurements. 



[Results of measurements by six observers, sliowing considerable discrepancies.] 



The Microscope, VII. (1887) pp. 10-2. 

 Glass, a New. 



[Similar to the ludicrous paragraph referred to ante, p. 155, and contains in addi- 

 tion the statement that " the difference between the new and the old glass 

 consists in the refraction of light ! "] 



Scientif. Enquirer, II. (1887) p. 47, from Boston Journ. of Commerce. 

 Glass, New Optical. 



[" The invention of a new optical glass is said to be creating a sensation in the 

 German scientific world. The glass, owing to its great refractory power, 

 promises to be of marked infiuence in practical optics, inasmuch as it will admit 

 of the production of lenses of short focal width, such as it has hitherto been 

 impossible to obtain. For microscopic photography it will be of the greatest 

 importance " !] 



Echo, 7th March, 1887. 

 H. — Measuring Refractive Index. 



[G. Thompson's method. See Journal, 1886, p. 698.] 



Amer. Mon. Micr. Journ., VIII. (1887) pp. 12-3. 

 Hoegh, E. v. — Eigenschaften der Jenenser Glassorten. (Properties of the Jena glass.) 

 [Refractive indices and dispersive powers of forty-four kinds of glass.] 



Central-Ztg. f. Optik. u. Mech., VIII. (1887) pp. 13-4. 

 May ALL, J., Jun. — See Taylor, J. T. 

 Measurement, Minute. 



[Micrometer Microscopes.] Knowledge, X. (1887) pp. 109-12 (3 figs.) (contd.) 



Nelson, E. M. — Numerical Aperture. 



[Reply to T. F. S. (p. 435), as to why an oil-immersion objective performs better 

 than a water-immersion of the same aperture. " Accounted for by slip (loss of 

 light by reflection, &c.) and unavoidable errors in construction."] 



Engl. Mech., XLIV. (1887) p. 480. 

 " ED ERIC Vital." — Schott & Co.'s New Optical Glass. 



[Contains a translation of the list of glasses. Cf. Journal, 1886, p. 856.] 



Engl. Mech., XLIV. (1887) pp. 523 and 563. 



PscHEiDL, W. — Bestimmung der Brennweite einer Concavlinse mittels des zusammen- 



gesetzten Mikroskopes. (Determination of the focal length of a concave lens by the 



compound Microscope.) 



[Find the position of an object in which the given concave lens produces an image 



half the size of the object itself; the distance b tween the image and object is 



then equal to one-half the focal length, if the thif knesa of the lens be neglected.] 



SB. K. Akad. Wiss. Wien, XCIV. (1886) p. 66. 



