178 SUMMARY OF CURRENT RESEARCHES RELATING TO 



MICROSCOPY. 



A. Instruments* Accessories, etc.* 

 (1) Stands. 



Swift's Sideros Metallurgical Microscope.! — This instrument 

 (fig. 16), which was built according to the suggestion of J. E. Stead, 

 F.R.S., is well suited for use in the laboratories attached to steel and 

 iron works. The stage, which measures 1 in. by 3f in., is focused by 

 means of a rack-and-pinion. In order to allow of the use of very low 

 powers, such as a 4-in. objective, additional coarse focusing is obtained 

 by sliding the optical tube in its cloth-lined fitting, and this fitting' is 

 provided with a clamp-screw so that no movement shall take place 

 after having been set. There is also a fine-adjustment capable of 

 focusing the highest power immersion objectives. 



This stand is well adapted for use with the Swift attachable Cone 

 Camera, and has at the upper end of the optical tube a fitting to 

 carry it. 



Nelson, E. M. — Binocular Microscopes. 



[The author gives a very interesting review of the types and principles of 

 the best known instruments.] 



Journ. Quekett Micr. Club, xii. (Nov. 1914) pp. 369-80. 



(2) Eye-pieces and Objectives. 



Zeiss' New Object-glass, and a New Method of Illumination.; 

 E. M. Xelson describes this short-tube oil-immersion auxiliary, which 

 is made upon an entirely new plan, being nickelled all over, with the 

 front lens set in a push-tube, and not screwed up as usual. It is a ith of 

 OiKA. In the performance of this lens the corrections are very 

 perfect. Although no fluorite is used in its construction it is very 

 nearly apochromatic, and shows a considerable advance over semi- 

 apochromatism, for only a slight trace of outstanding blue can be seen. 

 Its defining power is quite remarkable, surpassing all object-glasses of 

 similar aperture i known to the author. On a M oiler's probe-platte of 

 sixty diatoms all are resolved except the two specimens of Amphi- 

 pleura pellucida. The lens is sufficiently powerful to do all that is 

 wanted in practical study, and, owing to its great working distance, it 

 does not pick up by capillary attraction an unfixed cover-glass. 



The lens is peculiarly suitable for the author's new method of resolv- 

 ing diatoms, for which he gives the following directions : — 1. Place the 

 diatom so that the stria to be resolved are vertical in the field. 2. Set 



* This subdivision contains (1) Stands ; (2) Eye-pieces and Objectives ; (3) 

 Illuminating and other Apparatus ; (4) Photomicrography ; (5) Microscopical 

 Optics and Manipulation ; (6) Miscellaneous. 



t James Swift and Son's Catalogue, 1914, pp. 36-7. 



X Journ. Quekett Micr. Club, xii. (Nov. 1914) pp. 363-6. 



