ELECTRICAL APPARATUS. 261 



the electrical shock will be felt, and the jar will thus be 

 discharged. Price, pint, $1.00 and $1.25. 



" quart, $1.25. 



" half gallon, $1.75. 



" gallon, $2.50. 



Discharger. (Fig. 277.) 

 This is formed of two wires 

 with balls at the outer ends, 

 and jointed at the lower ends 

 where they are received into 

 a socket, into which a glass 

 handle is fastened. Hold the 

 common discharging rod firm- 

 ly, and discharge a phial by 

 it, he will not receive a shock. 

 If the phial be a very large 

 one, or if he hold it lightly, 

 he will feel perhaps a slight 

 tingling of the fingers when 

 the shock passes, but this is 

 all. If he be furnished with 

 the glass-handled discharging rod, or jointed discharging 

 rod, as it is called, he may, by setting its knobs at a proper 

 distance, discharge even the largest battery without danger. 

 It is usual for the sake of convenience to fasten a chain to 

 one of the arms of the discharging rod, which communicates 

 with the outside of the phial. 



Price, $1.25 to $2.00. 



" with moveable joints, $3.00 and $4.00. 



Pith Ball Electrometer (Fig. 278, next page) consists 

 of a small stand, supporting a glass rod, bent at right angles 

 at the top, and having a hole to attach a pith ball, which is 

 suspended by a silk string. If an excited glass tube be 

 held near the electrometer, the ball will be attracted, and 

 after adhering for a short time, it will be repelled to a con- 

 siderable distance, nor will it again be attracted until it has 

 touched some body connected with the earth, and thus given 

 up the electricity which it had acquired from the tube, or 

 until, by remaining undisturbed for some time, it has lost it 

 by dissipation into the atmosphere. Price, 50 cts. 



