S CIENCE- G OS SI P. 



" London " microscope, was in many respects a 

 notable departure. (See SciENGE-GossiP, vol. vii., 

 p. 184.) They have, however, designed and now 

 completed an entirelj^ new stand for advanced and 

 " critical " work, which deserves extended notice 

 in these columns, owing to several important fea- 

 tures. The stand is of full size, and is made either 

 with the Continental horseshoe foot or the English 

 tripod, as may be preferred, the latter being of a 

 massive form, with a spread of SJ and 9 inches. 

 There is a lever to clamp the position of inclina- 

 tion. The main body-tulDe has a diameter of no 

 less than 2 inches and a length of only 3| inches, 

 whilst, with nose-piece and closed draw-tubes in- 

 cluded, it mea-i\res 5| inches long. The advantage 

 of a wide tube is evident to all photo-micrographers, 

 and in this case the nose-piece and draw -tubes can 

 be removed and a wide-angle photographic lens 

 mounted for low-power work. There are two draw- 

 tubes, one of which is controlled by rack and 

 pinion, and has the universal screw at its lower 

 end. Both tubes are graduated in millimetres, 

 and they give a total extension of 260 mm. The 

 diameter of the tube is R.M.S. No. 4 gauge, 

 1-41 inches, which is the largest size, and an 

 adapter takes the No. 1 size, -917 inch. This 

 enables a large field to be used with low-power 

 eye-pieces. A smaller-size body, with single draw- 

 tube varying from 140 to 200 mm. only, is supplied 

 with the simpler forms of this microscope. The 

 coarse adjustment is of the usual sjjiral rack and 

 pinion form, working in dovetail grooves, but the 

 milled heads are large, and when at its highest 

 point the nose-piece is over 4 inches from the stage. 

 The fine adjustment is the new two-speed arrange- 

 ment of Mr. A. Ashe, in which two milled heads rotate 

 upon the same axis. The upper milled head 

 actuates a screw with a rather coarse thread, giving 

 a movement of jjg-inch per revolution, and this 

 works within an outer and finely cut screw actuated 

 by the lower milled head, and giving a movement 

 of 3^g-inch per revolution. The point of the inner 

 screw moves a lever carrying the body-tube. The 

 advantages of these two convenient movements 

 are obvious, and Messrs. Beck have every confidence 

 that they will prove entirely durable. The stage 

 is circular, and is five inches in diameter. It is 

 provided with centering screws, rack and pinion 

 for rotation, and is graduated on the periphery in 

 degrees. There is a removable mechanical stage, 

 also graduated, and provided with vertical pinions, 

 so that complete rotation can be obtained. One 

 of the advantages of this form of mechanical stage 

 is its non-liability to foul the top of the condenser. 

 The simpler models have a large stage 4J inches 

 square, with removable mechanical stage. The 

 sub-stage has centering screws, and rack and 

 pinion coarse and micrometer screw lever fine 

 adjustments. The sub-stage does not swing out, 

 but the ojDtical portion of the condenser can be 

 arranged to do so, the iris diajphragm swinging- 

 aside first to enable this to be done. The mirrors 

 are 2^ inches in diameter. The price of the 

 "Imperial" microscope in its complete form, as 

 described, without swing-out adapter for condenser, 

 is £29 12s. 6d. with the tripod foot, and £27 12s. 6d. 

 with the horseshoe foot. Either or all of the 

 following can be omitted, however — i.e. fine adjust- 

 ment to sub-stage, centering screws to stage, rack 

 and pinion rotation to stage, and graduations to 

 periphery of stage. An ordinary square stage with 

 mechanical adjustments can be fitted instead of the 



concentric rotating mechanical stage, the micro- 

 scope then costing £20 for the tripod form and 

 £1S for the horseshoe form. In its simplest form, 

 with small body taking -917 eye-piece and single 

 graduated draw-tube, the stand costs 30s. less. 

 This microscope is also made with a binocular 

 body, interchangeable or otherwise. 



Students' Series of Botanical Slides. — 

 In vol. vi., p. 124, of this magazine we called atten- 

 tion to the excellent series of botanical slides — 

 forty-eight in all — issued by Messrs. Flatters & 

 Garnett, of Manchester, for the very modest sum 

 of one guinea. With these is now sent out a book 

 of diagrams, price Is., di'awn by Miss Jennie 

 Payne, in which each slide is separately figured 

 and the various histological structures clearly 

 pointed out. The educational value of the slides 

 is by this means greatly increased, especially for 

 those whose studies in'botany have been guided 

 by no other teacher than a text-book upon the 

 subject, and we can imagine few things more 

 interesting to any microscopist who is still a 

 student of elementary or even advanced botany 

 than the study of these slides, with the help of the 

 diagrams and a good text-book in addition. If 

 the text-book should happen to be " Strasburger 

 & Hillhouse," the student will not rest until he has 

 endeavoured to emulate Mr. Flatters' beautiful pre- 

 parations, and will thereby, gain pleasure equal to 

 his profit. Truly the path of the learner is now 

 made plain before him. We understand that Mr. 

 Flatters has generously presented the Postal 

 Microscopical Society, selections from whose note- 

 books appear monthly in our columns, with a com- 

 plete set of these slides and diagrams. 



Paraffin Embedding in Vacuo. — The 

 " Journal of the Royal Microscopical Society " 

 mentions a method of paraffin embedding Mi 'ya^/o, 

 contributed by Dr. R. Kolster to the " Zeitschrift 

 fiir wissenschaftliche Mikroscopie." Dr. Kolster 

 uses chloroform, xylol, or toluol as solvents, and 

 after saturating the pieces in the usual way places 

 them under the air-pump and exhausts the air. 

 In the vacuum the last traces of the volatile 

 solvent or of air are removed, and a solid homo- 

 geneous block remains. 



MEETINGS OF MICROSCOPICAL SOCIETIES. 



Royal Microscopical Society. — 20 Hanover 

 Square, W., March 19th, 8 p.m. 



Quekett Microscopical Club. — 20 Hanover 

 Square, W., March 7th, 7 p.m. ; March 21st, 8 p.m, 



Manchester Microscopical Society.— Grand 

 Hotel, Manchester, March 6th, 7 p.m. ; mounting 

 section, March 20th, 7 p.m. 



Sunderland Microscopical Society. — Sub- 

 scription Library, Sunderland, March 18th, 7.30p.m. 



ANSWERS TO CORRESPONDENTS. 



W. D. W. (Dublin).— The drawback to the spiral 

 focussing sub-stage is that it is less rigid than the 

 rack-and-pinion arrangement, whilst the latter has 

 also centering screws, a necessary addition with 

 high-power and critical work. A complete speci- 

 fication for Beck's " London " microscope would be : 

 Stand No. 1,152 (stage, 4" x 4", clamp to iuclina 

 tion, graduated draw-tube, divided milled head to 

 fine adjustment, and rack-and-pinion focussing sub- 

 stage with centering screws), in mahogany case 

 £6 10s. ; two eye-pieces, Nos. 1 and 2, each 5s. ; 



