716 



RECOED OF CURRENT RESEARCHES RELATING TO 



in tlic stage. Ui3on the stage is a compressorium. The bar is first 

 brouglit close to the pillar of the Microscope, and the compressorium 

 moved along it until all the flesh in that strip has been examined. 

 The bar is then, by means of the adjusting screw h, advanced for a 

 distance equal to the diameter of the field of view, and the compres- 

 sorium is then moved in the reverse direction, and so on. The square a 

 is said * to be a small scale for the purpose of determining the extent 

 of movement each time. On account of the depth of the compres- 

 sorium, it must be reversed in order to examine it comi^letely. 



Matthews' Improved Turntable. — There have been many im- 

 provements suggested in microscopical turntables, most of which have 

 dealt with the means for securing the glass slide upon the table. Very 

 few improvements have been made in the means for imparting the 

 necessary rotatory movement to the table, and none which have come 

 into general use. 



Dr. Matthews' invention has for its chief object to provide a 

 ready and efficient means for obtaining a rapid and steady rotary 

 motion to the table, without adding materially to its complexity and 

 consequent cost, as at present constructed. This object he effects 

 thus : — 



Fig. 64 is a plan view of the machine, and Fig. 65 a side view of 

 the same, both figures being drawn \ size. 



Fig. 64. 



A A is a base-board of mahogany, upon which is erected the plat- 

 form B which serves as a support for the wrist of the operator. This 

 platform is hinged at h, so that it can be turned up out of the way 

 when desired. Near the front end of the base-board A is secured a 

 pivot-pin c'. Upon this pivot-pin is mounted, so as to turn freely, 

 a broad flanged pulley D. Above this pulley is mounted the 

 turntable E, also turning freely upon the pivot-pin. The under 

 side of the turntable is provided with a short neck e, having a ring of 

 ratchet teeth. The upper flange of the pulley is fitted with a spring 

 pawl d, which engages with the ring of ratchet teeth on the under side 

 of the turntable. Underneath the platform B a flat spring F is 

 secured by one of its ends, and to the free end of this spring is attached 

 a cord, which is led forward and passed around the pulley. It is then 

 carried over a second pulley G, from which it hangs pendent. 



* The figure is a ' cliche ' from tlie original woodcut. 



