I. MICROSCOPES. 781 



which takes the place of a cover glass. By regulating the flame, the tem- 

 perature in the chamber, which is kept moist by the drop of water which 

 cannot evaporate, can be maintained perfectly constant for a long time, and 

 the development of microscopical organisms at a high temperature can be 

 observed. 



3640. Two Cases of Microscopic Objects. 



Voigt Sf Hochgesang, Gottingen. 



3640a. Cases of Microscopic Preparations. 



F. Enoch, London. 



3641. Microtome with Preparations, made by W. Apel, 

 mechanician to the University of Gottingen. 



Prof. W. Krause, Gottingen. 



This microtome is accurately described in Waldeyer's and De la Valette's 

 Archiv fur microscopischelAnatomie (earlier in Max. Schultze's Archiv), 1875, 

 vol. XI., p. 21 6, plate XIII. It cuts in a purely mechanical manner, more by 

 drawing than by pressing the knife, whilst any shifting either of the preparation 

 or of the cutter by the hand is excluded by the principle of the construction 

 of the microtome. The thickness of the section to be made can be read off 

 on a circular disc divided into degrees, which can easily be applied to the 

 instrument. Any other (much longer) knife can be substituted for the one 

 in the instrument ; the box in which the preparation is fixed can also be 

 changed. The knife can be moistened by means of an " irrigator " with either 

 alcohol or water, and th6 apparatus can be fastened to a wall so that the blade 

 of the knife is horizontal. A microscopical preparation containing two sec- 

 tions of different thicknesses made with the above apparatus is enclosed for 

 exhibition. 



3642. Holle's Drawing Apparatus for the Microscope. 



Cuno Rumann, Gottingen. 



The construction of the apparatus has just been completed, and only one 

 specimen has been made. 



An account of its leading peculiarities will be found in the paper enclosed. 



3643. Photograph of the Drawing Apparatus. 



Cuno Rumann, Gottingen. 



3644. Sectional View of Drawing Apparatus. 



Cuno Rumann, Gottingen. 



3645. Description of the apparatus of Prof. Grisebach, from 

 the " Nachrichten von der Konigl. Gesellschaft der Wissenschaften 

 zu Gottingen." Cuno Rumann, Gottingen. 



3646. Dr. Thomas' Stages (see also X. 21). 



Rud. Fung, Heidelberg. 



3647. Querschnitter, an Instrument for cutting under 

 the Microscope. Prof. Dr. V. Karstcn, Kiel. 



The nature and use of the apparatus are given in the accompanying treatise. 

 The instrument only differs from that described in having the curved piece 

 (Biigel) turned forwards. 



