ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 279 



the erection of the image by a prism at the lower end of the body- 

 tube immediately over the objective instead of over the eye-piece, 

 " so that any objective and any eye-piece can be used without any 

 trouble." and the convenient inclination of the tube. 



Bulloch's Improved "Biological" Microscope.* — Mr. Bulloch 

 has made further improvements in his " Biological Microscope," prin- 

 cipally in the substage. 



The substage and mirror-bars move independently, with the object 

 as a centre, as heretofore ; but immediately beneath the stage, just 

 above where the rackwork ends, the substage-bar is cut transversely and 

 the two parts joined together by a pinion and screw passing vertically 

 through lateral projections cast for the purpose. About this pin the 

 lower part, carrying the substage with its rack and centering screws, 

 swings laterally, entirely out from beneath the stage. The space 

 between stage and mirror is thus unobstructed by the substage, and 

 the substage itself is practically clear of the Microscope, where it can 

 be seen, and apparatus removed from or added to it with even more 

 facility than if it were held in the hand. 



Mr. Hitchcock regards it " as the greatest improvement in substage 

 fitting that has been made for years, and one that is sure to be appre- 

 ciated as its value becomes known." 



The substage-ring is also made in two parts, and the lower part 

 swings to one side independently. This part may carry a tinted 

 glass to modify the light, or the diaphragms of a condenser, which 

 could be conveniently changed. It would be better to place the 

 condenser and its diaphragms in the upper substage-ring, while the 

 polarizer with its plates of mica and selenite are fitted in the lower 

 ring. Such an arrangement would give the microscopist every facility 

 for work that could be desired. Without removing a single accessory, 

 he would be prepared to use the light directly from the mirror by 

 turning the substage aside. Then the condenser could be brought 

 into use by a single motion, and the different effects of oblique light 

 and dark-ground illumination obtained by the simplest possible 

 operation of changing diaphragms. By bringing in the polarizer, 

 which is always ready for use, all the effects of polarized light can 

 be obtained. 



Cox's Microscope with Concentric Movements.| — The Hon. 

 J. D. Cox describes the new features of this stand (fig. 29) to consist 

 in " the construction of the arm of the instrument in the form of the 

 segment of a circle in which is a circular groove or slot ; the pillars 

 of the base have on their inner faces tongues which fit the slot in the 

 arm. The inclination of the instrument is made by the sliding of 

 the whole body along the fixed tongues in the pillars of the base ; the 

 centre of motion of the whole body is also the optical centre of the 

 instrument, around which the stage, the substage bar, and the mirror 

 bar all revolve. The body is clamped up in any position by the set- 

 screw, with large milled head, in the base. The result is a shifting 



* Amer. Mon. Micr. Journ., v. (1884) pp. 9-10. 



t Proc. Amer. Boc. Micr., 6th Anu. Meeting, 1883, pp. 147-8 (1 fig.). 



