ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 723 



fitted with the Society thread to allow a 2 in. objective to be screwed 

 in. This combination is made to slide in another tube furnished 

 with a set-screw, in order that the inner tube carrying the optical 

 portion may be fixed in any required position. 



In use, the outer tube is jplaced in contact with the glass, and the 

 inner tube carrying the ocular and objective withdrawn until the 

 cross lines on the glass, made with the diamond, are exactly in focus. 

 When the focus is accurately obtained the set-screw is tightened, and 

 it follows that when the lower end of the outer tube is placed over 

 the transparent circles, the sharpest image must be in the same plane 

 as the diamond scratches, when its details are best seen with the 

 auxiliary Microscope. 



We can scarcely imagine a simpler or more accurate method than 

 the foregoing, nevertheless, some may object to it on the ground that 

 an auxiliary Microscope is required, and therefore another method is 

 given, which, if not so handy or so accurate as that already described, 

 has the merit at least of being inexpensive. A focusing slide is used, 

 in addition to the ground glass prepared as before described, and 

 this slide is pierced with a series of holes to take an ordinary ocular, 

 the A preferably. The first step is to secure the best focus on the 

 transparent circle, to the unaided eye, and the proboscis of the blow-fly 

 will be the best object to work with. When this is obtained, set the 

 eye-piece in the position of sharpest focus in the focusing slide, and 

 always use it in that position, which can be insured by a collar of 

 sufficient depth fitting up to the shoulder." 



Atlwaed's (H. p.) Camera Lucida. 



[_Ante, p. 593. " Mr. Aylward has made a further improvement in this 

 important accessory, and it is certainly not the least of its advantages that 

 it will fit any ocular of English pattern. It can be made to fit foreign 

 stands also."] 



Micr. News, III. (1883) pp. 237-8. 

 Banqueting a Microseopist. 



[At a banquet at Charlestown to Professor J. Leidy, a great delicacy was 

 served —tails of fishes having a tumour-like excrescence — this the Pro- 

 fessor found contained a tape-worm.] 



The Microscope, III. (1888) pp. 128-9, from The Bistmry. 

 Bausch, E. — Microscopical Illumination. Title only of U.S.A Patent 277869 of 

 2ith June, 1882. (Taken from Zeitschr. f. Instrumentenk., July 1883, 

 wrapper.) 

 Binghamton, N.Y., New Microscopical Society. 



Amer. Mon. Micr. Journ., IV. (1883) p. 140. 

 Beadburt, W.— The Achromatic Object-glass, XXVI.-XXVIII. 



Engl. Mech., XXXVII. (1883) pp. 498-9 (1 fig.), 

 521-2 (1 fig.), and 591-2 (1 fig.). 

 BusSEEEAU, B. — Nachef s Black-ground Illuminator. 



Micr. News, III. (1883) p. 236, transl. from Journ. de Phot, et Micr. 

 Ceowthee, H. See Harris, W. H. 

 Davis, G. E. — A Standard Body-tube for Microscopes. \_Supra, p. 713.] 



Micr. News, III. (1883) pp. 219-20, 264. 

 „ „ Focusing the Image in Photomicrography, \_8iipra, p. 722.] 



Micr. News, III. (1883) pp. 233-4 (1 fig.). 



DippEL, L. — Das Mikroskop und seine Anwendung. (The Microscope and its 



use.) Part I. Handbuch der allgemeinen Mikroskopie. (Handbook of 



General Microscopy.) Sec. 3. 2nd ed. 8vo, Braunschweig, 1883, pp. 737- 



1030, ix.-xviii. (figs. 507-79). 



