ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 303 



them being turned towards the eye." Proposed to be called '' an undis- 

 torted eye-piece, not because the distortion is absolutely 0, but because it 

 would seem to be much smaller than tiiat of those in use." 



Engl. Mech., XXXVIII. (1884) p. 541. 

 Physicians, Microscopes for. 



[Recommendation of Beck's ' Economic.'] 



Cine. Med. News, XVI. (1883) pp. 833-4. 

 '' Prlsmatique." — Object-glass working, XI. 



Engl Mech., XXXIX. (1884) p. 24. 

 Prize, Questions for Examination in Competition for Bulloch and Grunow's. 



4to, 1 p. (11th February, 1884). 

 [Seventeen questions on optics, lenses, objectives, camera lucida, magnifying 

 powers, diffraction, and mounting. Open to any student in the senior 

 class for five years of the Chicago Medical College.] 

 Queen's (J. W. & Co.) New Spot-lens Mounting. IPost^ 



Micr. Bull., I. (1884) p. 11 (3 figs.). 

 EoGERS, W. A. — Corrections to paper on the " Conditions of success in the con- 

 struction and the comparison of standards of length." 



Proc. Amer. Soc. Micr., 6th Ann. Meeting (1883) pp. 240-1. 

 EoHEBACH, C. — A new fiuid of great specific gravity, of large index of refraction, 

 and of great dispersion. 



[100 parts of iodide of barium are mixed with 130 parts of scarlet biniodide 

 of mercury. About 200 cc. of distilled water are added to the powders, 

 and they are then stirred up with a glass rod while heated in a test-tube 

 plunged into an oil bath previously warmed to 150° or 200° C. A fluid 

 double iodide of mercury and barium is formed, which is then poured 

 into a shallow porcelain dish and evaporated down until it acquires a 

 density so great that a crystal of epidote no longer sinks in it. When 

 cold even topaz will float in it. It is then filtered through glass-wool. 

 Tlie fluid so prepared has a density of 3 -575-3 '588, boils at about 145°, 

 and is of a yellow colour. Its refractive index is 1 • 7755 for the C line, 

 and 1 • 8265 for the B line of the spectrum. For the two D lines of sodium 

 the refractive indices are 1 ' 7931 and 1-7933 respectively. So great is the 

 dispersion that, using a single hollow prism with a refracting power of 

 60°, the dispersion between the two D lines is almost exactly 2' of angle.] 



Amer. Journ. Sci., XXVI. (1883) p. 406. 

 from Ann. Physik u. Chem., No. 9, pp. 169-74. 

 Seip, a. — Address to the Lehigh Valley Microscopical Society. 

 (On the value of the Microscope.] 



Amer. Mon. Micr. Journ., V. (1884) pp. 39-40. 

 Slack, H. J. — Pleasant Hours with the Microscope, 

 [Horizontal position of Microscope. Post.'] 



Knowledge, V., (1884) pp. 109-10. 

 Stoddee, C, Death of. Micr. Bull., I. (1884) p. 9. 



Am,er. Mon. Micr. Journ., V. (1884) pp. 55-6. 

 Stoeies, a. W. — Simple apparatus for aerating living fish whilst imder micro- 

 scopical observation. \_Supra, p. 286.] 



Journ. Quek. Micr. Club, I. (1884) pp. 322-3 (2 figs.). 

 Stowell, C. H. — Gleanings from the Journ. R.M.S. for December. 



[Claims for Mr. E. H. Griffith tlie invention of a Revolver Microscope 

 similar to Mirand's, III. (1883) p. 897, and of a nose-piece adapter similar 

 to Matthews's, ibid., p. 903.] 



The Microscope, IV. (1884) pp. 35-7. 

 Stowell, C. H. and L. E. — Proceedings of the American Society. 

 [Urging earlier publication.] 



The Microscope, IV. (1884) p. 39. 

 Washington Microscopical Society, formation of. 



Amer. Mon, Micr. Journ., V. (1884) p. 58. 

 Wassell, H. a. — Plate Glass for Optical work. 



Engl. Mech., XXXIX. (1884) p. 57. 

 Webb, T. W. — Optics without Mathematics. 8vo, London, n.d., 124 pp. and 58 

 figs. [Microscope, pp. 61-6, 107-8. Supra, p. 300.] 



