45, COENHILL,|E.C., AND 122, BEGENT STEEET, w., LONDON. 



^ttitf^ 



461 



FIG. 2801. 



FIG. 2801*. 



ELECTRIC TELEGRAPH APPARATUS. 



2801 



Model Telegraph Instruments, consisting of two Single Needle Instruments 

 with Signal Bells and communicators, for exhibiting and explaining 

 telegraphic communication (figs. 2801 and 2801*). These instruments 

 will be found useful to learners of Telegraphy, 



The complete Set of two Needle Instruments with Bells attached 5 10 

 Leclanche Batteries for working the above through short distances, Single 



Cells, see also page 8s. 6d. and 10s. 6d. each. 



Six-Cell Smee's Batteries (fig. 2803), for Telegraph use, conveniently arranged 

 in a stout framed tray, with Ratchet Movement for immersing the elements 

 to any desired depth in the acid according to the action required, or for 

 entirely withdrawing them when out of use . . Price 4 10 

 Smee's Batteries when charged with extremely dilute acid will be found to act 

 very well for some considerable time without much attention. 



For particulars of Leclanche and other Batteries, see pages 428 to 434. 



2802 



2803 



FIG. 2804. 



FIG. 2806. 



2804 



Portable Sick Room and Invalid's Electrical Bell and Battery combined, 

 in a mahogany case, for temporary service. Specially adapted for the use 

 of invalids, with 30 yards of flexible Wire Cord and Presselle, &c. (fig. 2804) 



440 



