ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



411 



change could be made without altering the focus of the Microscope, 

 and causing a loss of time in readjusting the focus and in finding the' 

 particular part of the object. By the rotating live-box no alteration 

 of the focus is necessary." 



Schklarewski's Hot- water Stage.*— This is represented in Fig. 

 76. The water, heated by gas or a spirit lamp, passes from the 

 vessel C, through the tube a, into the hollow stage O placed on the 

 microscope-stand A. A thermometer T shows the temperature. The 



Fig. 76. 



water, after passing through the stage and becoming cool, flows back 

 again through h into the vessel C, whilst that which is more heated 

 flows through c, and the indiarubber tube attached to it, into another 

 receptacle. The stage does not appear to differ essentially from other 

 well-known forms. 



Abbe's Condenser. — This apparatus as originally devised f was 

 not easily applicable to any stand but that of Zeiss for which it was 

 specially made. It has now been so modified (Figs. 77 and 78) that 

 it can be applied to the usual substage fitting. 



The upper lens A is a thick plano-convex, somewhat larger than 

 a hemisphere. Just below it is a large bi-convex lens serving' as a 

 collecting lens to A. The upper focus of the combination is about 

 2 mm. (in glass) above the plane face of A, that is, about the distance 

 of an object on an ordinary slide. A small metal cap with a central 

 pin-hole can be placed over A for convenience of centering. B is a 

 box-fitting for diaphragms, &c., forming part of the carrier-plate C, 



* Thanhoffer"s 'Das Mikroskop uad seine Anwendung,' 1880, pp. 88-9 

 (1 fig-)- 



t Mon. Micr. Journ., xiii. (1875) pp. 77-82 (1 fig.^. 



2 E 2 



