SCIENCE-GOSSIP. 



29 



CONDUCTED BV V. SHII-LINGTOX SCALES, I-'.R.M.S. 



To MiCROSCOPisTS.— With this number Science- 

 Gossn- begins a fresh volume, and the microscopical 

 column comes under new editorship. A few intro- 

 ductor)- words as to our aims may, therefore, not be 

 out of place. Our object is to make this column as 

 interesting and as helpful as possible to our readers, 

 by keeping them informed of various matters of 

 interest in the microscopical world, especially with 

 reference to methods of work. We propose in future 

 to lay greater stress, from time to time, upon the 

 improvement of the microscope and its accessories. We 

 desire, in fact, to make this column a valuable record 

 of the progress of the microscope, of new or 

 modified stands, objectives, apparatus, etc. The 

 present keen competition amongst opticians, especially 

 amongst the limited few who are in the front 

 rank, and with whom workers are mostly concerned, 

 gives rise to constant progress. It will beour endeavour 

 to keep our readers advised on these points without fear 

 and without favour. May we add that we shall espe- 

 cially welcome letters from our readers, who have, 

 we think, scarcely realised how much help they may 

 gain, or give, by taking advantage of the free hos- 

 pitality of these columns. We shall ourselves be glad 

 to answer through this medium any enquiries on 

 miscropical matters that ma\- be sent us if addressed 

 to the office of Science-Gossip. 



Cleaning Slides. — We can recommend the 

 method mentioned by Mr. Cole for cleaning glass 

 slips and co\ers, whether used or not, namely to 

 immerse them bodily in a strong solution of Hudson's 

 soap-powder in warm water. Soak for an hour or two, 

 wash well with changes of warm water, and finally, if 

 necessary, with methylated spirit. Cover glasses 

 and slips for important work may require special 

 methods. 



New Achromatic Condenser.— Although the 

 Abbe Condenser, or, as it is often called, Illuminalor, 

 is recognised as being suitable for most general 



R. & J. Beck's New Condenser 



practical work, mainly on account of its being easy to 

 use,, yet for more critical work a well corrected 

 condenser becomes a necessity. Messrs. Beck ha\e 

 brought out a new condenser for high-power work 

 that is achromatic and has a numerical aperture of 



\ 



I .^'- -^- 7"*^'^ '■'* ''^'-' ■>ia''i'ii"ii> lliat can be obtained 

 without having the front of the condenser in immersion 

 contact with the under surface of the slide, and its 

 aplaiialic aperture exceeds -9 X.A. It is thus greatly 

 superior to the ordinary Abbe Illuminator. The front 

 lens is removable to make a low-power condenser. 

 An Iris diaphragm and a swinging arm, with rotating 

 fitting for coloured glasses, or stops, are provided. 

 A bracket is ingeniously added at the bottom of the 

 mount, into which the optical portion may be 

 screwed, and the whole condenser thus reversed. 

 This is often a convenience. The price of the 

 complete condenser is £1, but with Iris diaphragm 

 only £z 5s. 



New Triple Nosepiece.— Messrs. Beck have also 

 brought out a new triple nosepiece in bright lacquered 

 brass, the price of which is only seventeen shillings 



Becks New Triple Nosepiece. 



and si.xpence. It is not perhaps quite so attractive as 

 the ordinary trefoil-shaped pattern, but has the advan- 

 tage of being dust-proof and cheap. 



New Reversible Compressor.— A third novelty 

 which the above firm have brought under our notice 

 is a new reversible compressor, designed by Mr. H. R. 

 Davis. Briefly, we may say that it is made of 

 ebonite, and consists of a lower and two upper plates. 

 The lower plate contains an oblong thin glass, held in 

 position by two screws, the two upper plates contain 



The Dax'is Reversible Compressor. 



a projecting milled ring, which, when revolved, 

 brings an upper thin glass in contact with the lower 

 glass. The whole arrangement is easily taken apart 

 and conveniently arranged, whilst it is eminently 

 serviceable. The price is los. 6d. 



Dissecting Microscopes. — Messrs. Bausch and 

 Lomb have brought out two new dissecting micro- 

 scopes. The one consists of a small wooden case or 

 box, 4 inches X 2 inchesXiA inches. One end of the 

 case and the top is removable, and sen-es as a cover. 

 A small glass stage slides in a groove at the top of the 

 box, and can be replaced by a glass stage with cell, 

 opal glass stage, or black glass stage. Beneath is a 

 plane mirror, and an upright rod carries three lenses, 

 magnifying from 5 to 25 diameters. The other dis- 

 secting microscope is very similar to Leitz' well- 

 known stand, but the focussing is by sliding adjust- 

 ment instead of by rack and pinion. 



Abbe Camera Lvcida. — Messrs. Bausch and 

 Lomb have also brought out a simplified form of this 

 camera, in which the mirror and prism are enclosed 



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