928 SEC. 18. BIOLOGY. 



with central aperture for the object is placed on the upper 

 surface of the disc, thus closing the aperture. The lateral move- 

 ment of the microscope with the coppering is effected by a plate 

 at the bottom of the apparatus on which the microscope is fixed. 

 The same can be shifted in two direction?, at right angles to one 

 another by means of micrometer-screws. Four side-apertures 

 admit the introduction of thermometers or liquids for keeping the 

 chamber moist, or for the infusion of gas. A small gas-flame, 

 which imparts heat to the adjoining piece, serves as a heat conductor. 

 The Imperial and lioyal Pathological and Anatomical 



Institute of the University of Prague (Director, Prof. 



Edwin Klebs). 



3668. Microtome. A circular knife is set revolving by a 

 turning-lathe. The preparations, which are embedded in a metal 

 case, are moved forward by a micrometer screw, and passed across 

 the edge of the rotating knife by a contrivance similar to that in a 

 dividing engine. 



The Imperial and Royal Pathological and Anatomical 

 Institute of the University of Prague (Director, Prof. 

 Edwin Klebs). 



3668a. Holman's Syphon Slide, invented to keep objects 

 alive while under the microscope by a flow of cold water. 



D. S. Hotmail, Philadelphia. 



3668b. Holman's life Slide. 



D. S. Holman, Philadelphia. 



By the cross groove causing live objects, such as vinegar eels, &c., to take 

 up their position in it, they are enabled to be more readily examined. 



3668c. Holman's Current Slide. 



D. S. Holman, Philadelphia. 



3668a. Fifteen Frames, containing photographs of Micro- 

 scopical Sections. Richard Daintree. 



II._OPHTHALMOLOGICAL APPARATUS. 

 a. OPHTHALMOMETEES. 



3692. Qphthalmometer, according to the directions of Pro- 

 fessor Helmholtz. 



Aug. Becker (Dr. Meyer stein's Astronomical and Physical 

 Workshops), Gottingen. 



3693. Mirror Apparatus for the above, for measuring the 

 radius of curvature of the different meridians, with balancing 

 weight. 



Aug. Becker (Dr. Meyer stein's Astronomical and Physical 

 Workshops), Gottingen. 



