808 



SUMMARY OF CURBENT RESEARCHES RELATING TO 



5-13 mm., or from 7—15 mm., according to the clamp used, and may also 

 be round, oval, triangular, square, or flat in section. The construction is 

 as follows (fig. 217). 



On the pin A having a hook-shaped head, is the cup B, the clamp C, 

 and the nut D, which is provided with a washer. D works upon a screw- 

 thread on the pin, and when screwed up presses together the clamp C and 

 the cup B, by which the bar H is clamped in the angle of C, while on the 

 other side the hook draws the cup against the upright J, so that J and H 

 are firmly clamped together by the single screw D. 



Fir. 217. 



Fig. 218, 



Swift's Lever and Parallel-spring Fine-adjustment. — Messrs. Swift 

 and Son, as noted supra, p. 218, have applied a lever to the parallel- 

 spring fine-adjustment of Bausch and Lomb by which the speed of the 

 movement is much lessened. The mechanism is shown in fig. 218 (reduced 

 from the drawing to the specification of the patent). 



The milled-head screw acts upon the lever B, the short end of which 

 engages in the piece C, which is attached to the body-tube E, and is 

 supported at the back hy the parallel springs D D connected with the 

 stem. 



The movement of the screw raises or lowers C at a very slow rate against 

 the tension of the springs DD. 



Neumann, C. — Die Brillen, das dioptrische Fernrohr und Mikroskop. Handbuch fiir 



praktische Optiker, (Spectacles, tlie dioptric Telescope and Microscope. Handbook 



for practical opticians.) 256 pp. and 60 figs., 8vo, Wien, 1887. 



Stein, S. T.— Die Optisclie Projektionskunst im Dienste der exakten Wissenschaften. 



(The art of optical projection in aid of the exact sciences.) 



[Reprint from Part V. of ' Das Licht.' Of. ante, p. 161. Contains a chapter on 

 "the Projection of Microscopic Objects."] 



viii. and 155 pp., 183 figs., 8vo, Halle a. S., 1887. 



Woodhead's microscope with large stage for the examination of sections through entire 



organs. Brit Med. Jouni., 1S87, No. 1391, p. 469. 



