926 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



The increase of force in this case is due mostly to the propor- 

 tionally diminishing resistance. In this arrangement the total 

 interior resistance is not increased when we increase the number 

 of cups. If a battery is composed of one cup, a given resistance 

 is overcome by it ; if the number is increased (the cups being 

 equal), the same resistance is divided among them, and that shared 

 by each is diminished as the number is increased. 



Fourth case : 



8imple battery, with quantity galvanometer^ gave the following 

 deflections, viz : 



One cup _ 9° 



Two cups 18° 40' 



Three cups 26° 20' 



Four cups 31° 40' 



The cups individually gave the following deflections: 9°, 10° 40', 

 11° 30', and 10° 30'. 



It is astonishing to observe how exceedingly sensitive this gal- 

 vanometer is to the least possible amount of resistance, either inte- 

 rior or exterior. The extra wires necessary for connecting the 

 several cups, produced appreciable eflects, and changes in the 

 relative position of the zinc and copper plates of one cup produced 

 effects as follows, the deflections by the intensity galvanometer 

 being at the same time noted : 



Deflections. 



Distance of plates apart. Quantity gal. Intensity gal. 



Oneinch 32° 62° 45' 



Two inch.: 25° 63° 



Three inch 20° 62° 45' 



Fourinch ' 16° 10' 62° 30' 



"This shows how a large quantity is affected by resistance of any 

 kind, and how very little intensity is aftected by interior resistance. 



I hope I have succeeded in giving some appreciable illustration 

 of the two distinct properties, quantity and intensity. 



The batteries most used in telegraphy are Smee's Sulphuric 

 Acid Battery, Grove's Nitric Acid Battery, the Chromic Acid Bat- 

 tery, and some forms of the Sulphate of Copper Battery. 



Smee^s battery has gone nearly out of use, on account of the 

 inconstancy of its current. When a circuit is tirst closed upon it, 

 ■It fcitapts off with great energy ; but the counteracting eflect of the 



