ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



607 



DiatomacesB from the Island of Socotra.* — F. Kitton gives a list 

 of twenty-tno fresh-water species from the Island of Socotra. 

 Amongst these are a new species of Cerataulus (C, Sodrensis), which 

 is the first fresh-water representative of the genus, and Fragilaria 

 Ungeriana Gruu., which has previously been found in only two 

 localities — Cyprus and Belgaum (India). 



MICROSCOPY. 



a. Instruments, Accessories, &c. 



Microscope with Amplifiers. — Fig. 89 shows two methods of 

 applying a series of amplifiers to the Microscope : — (1) A disk contain- 

 ing four apertures is mounted 

 above the nose-piece to rotate Fig. 89. 



so as to bring the apertures 

 successively into the optic axis. 

 One aperture is blank for 

 normal examinations ; and the 

 others are provided with bi- 

 concave lenses of 3 in., 4 in., 

 and 5 in. negative focus re- 

 spectively. This application 

 of amplifiers was exhibited at 

 the Society several years ago, 

 but we have not succeeded in 

 tracing the name of the ex- 

 hibitor. (2) Mr. J. Mayall, 

 jun., suggests that the ampli- 

 fiers should be mounted in a 

 plate (shown in the fig.) sliding 

 through the body-tube, and 

 with means of raising or lower- 

 ing it within the body-tube so 

 that the best position with each 

 objective may be found experi- 

 mentally. 



The use of such amplifiers ia 

 involves a slight deterioration 

 of the quality of the image, but 

 in many cases this would bo 

 more than compensated by the 

 increase in the magnification 

 and in the working distance. 



Bausch's Binocular Microscope, t— The following is E. Bausch's 

 specification of his " Binocular Microscope " : — 



" My invention relates to the class of Microscopes in which part 

 of the rays of liglit emanating from the object and passing through 



• Journ. Linn. Boc. Loud.— Uot., xx. (J881) pp. 5i:{ .0 (1 p].). 



t birtjcification of U.S.A. I'utcnt No. 293,217, dated iVbruary 12Lh, ISbl. 



