526 SUMMARY OF CURRENT RESEARCHES RELATING TO 



other branches of critical research woi'k. One of the outstanding 

 features of this stand is that it is swung through an arc on the "Wales 

 principle instead of being inclined by the usual axis joint, and is as 

 steady and rigid in the horizontal as in the vertical position. The 

 rotating mechanical stage has centring screws and can be rotated through 

 an entire circle. The mechanical movements are so arranged that the 

 entire surface of a :'')-in. by 1-in. slide can be systematically exaiDined. 

 To allow of the use of a Petri dish the horizontal movement of the 

 mechanical stage can be instantly removed, while for rough work the 

 entire mechanical stage can be taken away and for it a plain vulcanite 

 covered rotating stage can be substituted. The coarse-adjustment is of 

 the usual diagonal rack-and-pinion type, while the fine-adjustment is 

 the improved "' Chmax " pattern ; one division on the divided drum of 

 fine-adjustment corresponds to a movement of 0*001 mm. of the tube. 

 An achromatic condenser is always fitted to this instrument ; this con- 

 denser is provided with centring screws and also with the Continental 

 type of iris diaphragm, which can be racked excentrically and rotated 

 to allow of the use of illumination from any azimuth. This diaphragm 

 can be swung aside right out of the optic axis quite independently of 

 the condenser. 



(2) Eye-pieces and Objectives. 



Simple Demonstration Ocular.* — K. Shiino describes the following 

 simple device for directing the attention of a student to any required 

 position in the image. It is based on the same idea as Kuznitzky's 

 pointer, but has the advantage of being applicable to every ocular. 

 The author merely places a short pointed hair between two ring-shaped 

 paper disks gummed together, and rests the whole arrangement on the 

 diaphragm of the ocular. The hair is of such a length that it does not 

 reach the centre of the field. It is therefore excentric and its point 

 describes a small circle as the ocular is rotated. The hair is so fine 

 that it does not interfere with the image, and it can easily be directed 

 towards any required spot. 



(3) Illuminating- and other Apparatus. 



Practical Object-holder for the Microscopical Examination and 

 Demonstration of Mobile Objects (Test-tubes* Capillary-tubes, etc.).t 

 C. Strzyzowski, after referring to the difficulty often experienced in the 

 examination of sublimates and such-like objects in tubes, describes the 

 following simple device which he has found very useful. A plate of 

 metal shaped like an ordinary object-slide is channelled longitudinally 

 for the reception of the tube, and is secured to the Microscope-stage 

 by a small G -cramp. The plate is perforated in the middle for the 

 transmission of the light, and the glass tube is kept steady by a 

 spring-clamp. 



* Zeitschr. wiss. Mikrosk., xxix. (1913) pp. 321-2 (2 figs.), 

 t Zeitschr. wiss. Mikrosk., xxix. (1913) pp. 323-4 (2 figs.). 



