402 SUMMARY OF CURRENT RESEARCHES RELATING TO 



where it has been several times described. It cousists primarily of a 

 small wooden case A, about one-third larger than shown in the figure. 

 To one end of the lid B is attached one of the ends C of the case, and 

 when the lid is reversed it may be slid into the groove of the case, 

 and then forms a stand for the lenses and stage. These are supported 

 by a steel rod D, the lower end of which is hinged to the lid so that 

 it may be turned down and lie in the groove provided for it. When 

 raised into the jjositiou shown in the figure, it is held securely in 

 place by means of the button E, which also serves to retain it in the 

 groove when it is turned down. The glass stage G is fitted into a 

 frame of hard rubber, and slides easily on the stem D, so as to be 

 readily adjustable for focus, while at the same time it may be firmly 

 fixed by means of a set-screw, at any desired height, and will then 

 serve as a stage for dissecting purposes. The frame which holds the 

 lenses F (magnifying 5-30 diameters) fits on the top of the stem. A 

 mirror H is fitted into the case, and is readily adjustable by means of 

 the button I shown on the outside, so that light may be reflected up 

 through the stage when the objects to be examined are transparent. 

 When they are to be viewed by reflected light there is a dark plate 

 of hard rubber N, which is also carried by the stem D, and may be 

 turned under the stage so as to cut off all transmitted light. Dis- 

 secting needles (K and I), with handles, fit into appropriate grooves. 



The glass plate is fitted into the stage so as to form a cell capable 

 of holding water, so that dissection may be carried on under that 

 liquid, or aquatic animals may be kept alive and examined at leisure. 

 The stage may also be turned so that the flat side will be uppermost 

 if desired. When the lenses and stage are removed they are 

 readily packed in the case, and the entire instrument goes into a 

 compass " which readily admits of it being carried in the vest pocket." 



Dr. Phin recommends * that in order to increase the steadiness of 

 the instrument the case should be attached to a board 6 in. x 4 in. x 

 f in. A single small screw is sufficient, and the board can be easily 

 detached when it is desired to carry the Microscope in the pocket. 



Hartnack's Drawing Apparatus (His's Einbryograph).t — Dr. E. 

 Hartnack describes his new drawing apparatus, which is a modifica- 

 tion of the erabryograph of Professor His. He writes: — "It is 

 desirable for many purposes of natural history to trace exact out- 

 line drawings with low magnifying-powers, and to be able to regulate 

 the power so that it may be easy to pass from one scale to another. 

 The drawing apparatus hitherto employed in microscopy (even with 

 the use of low objectives) have hardly allowed the use of a power 

 less than 20 ; moreover, although through the movement of the tube 

 it was not impossible to obtain any scale desired, yet, at any rate, it 

 was not convenient. 



" A short time ago Professor W. His published f the design of a 

 drawing-apparatus which allowed the power to be varied at will from 

 4 to 40. He combined the Oberhauser camera with a small photo- 



* ' How to u?e the Microscope,' 4th ed., 1881. 



t Zeitschr. f. Instrumentenk., i. (1881) pp. 284-7 (1 fig). 



X ' Anatomie menschlicher Erabryonen,' fol., Leipzig, 1880. 



