1900] MICROSCOPICAL JOURNAL 71 



the same price. The price of the j-inch is $3.75, and of 

 the ^-iuch $7.25. We had also an opportunity of exam- 

 ining a 1-inch N. A. -26 at 158., and a 1-12-inch oil im- 

 mersion N. A. 1-3 at $24.50. This last was a really fine 

 lens. The microscope, as described above, with double 

 nose-piece, f and e inch objectives, two eye-pieces, and 

 mahogany case, is sold at $35.25, or with Abbe condenser 

 N. A. 1-2, with iris diaphragm, $7.25 extra. 



Standardization of Sub-stage and Draw-tubes. — 

 The Royal Microscopical Society, which has already done 

 so much for the standardization of the various parts of 

 the microscope, and whose standard for the thread of ob- 

 jectives, know as the "Society Screw," is now adopted by 

 opticians throught the world, has passed some important 

 resolutions with regard to the standardization of the sub- 

 stage and of the internal diameters of the draw-tubes of 

 microscopes. There are few workers who have not ex- 

 perienced the annoyance and diflBculties caused by the 

 present want of uniformity among our leading makers. 

 The present step is yet another in the direction of uni- 

 formity, though we could wish it had been a more firm 

 and decided one. As it is, it will not do away entirely 

 with the evil complained of, even if makers can be per- 

 suaded to adopt its somewhat various suggestions. The 

 resolutions arrived at by the Council on December 20 last 

 were : that the standards adopted by the Council in 1882 

 be withdrawn ; that the standard size for the inside di- 

 ameter of the sub-stage fitting be 1*527 inches (38 "786 

 mm.) ; than the guages for standardizing eye-pieces be the 

 internal diameters of the draw- tubes, the tightness of the 

 fit being left to the discretion of the manufacturers. Fur- 

 ther, that the following four sizes of the internal diame- 

 ters of the draw-tubes be adopted : — R. M. S. No. 1, .9173 

 inch (23.300 mm.); R. M. S. No. 2, 1-04 inches (26.416 

 mm.) ; R. M. S. No. 3, 1-27 inches (32.258 mm. j ; R. M. S. 

 No. 4, 1.41 inches (35-814 mm.) ; and that plug and ring 



