924 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



connected so as to make them equivalent to our large cup, as in 

 fimire 1. 



By intensity I mean that property which overcomes great 

 resistance and reudeijs the current efficacious in being propagated 

 , through long lines of telegraph wire, and in giving severe shocks 

 physiologically. This is obtained by a large number of cups, 

 which may be cither large or small, arranged in compound battery, 

 having the negative pole of one cup connected with the positive 

 of the next, and so on as in figure 2. Small cups give equal 

 intensity with large; hence, a cup formed of a gun cap, and charged 

 with a lady's tear, was said to give impulses through the Atlantic 

 cable, as strong as those from a cup of larger dimensions; but 

 small cups do not last as long as large ones. 



There is another property of a current, viz.: That which renders 

 it capable of being subdivided, and of intensely charging and 

 operating a number of long lines at the sam'e time. This is 

 obtained either by a large number of large cups, or a number of 

 parallel series of smaller cups, arranged as compound battery, 

 having the similar poles of the several series connected. A current 

 possessing this property I have presumed to call volume of inten- 

 sity. I do this with some diffidence, for I know that electricians 

 have considered it a simple combination of qiiantity and intensity, 

 and have not seemed to notice the distinction I am speaking of; 

 but it seems to me that no portion of this current can exhibit the 

 true properties of a quantity current. 



There is certainly one plain distinction, i. e., it does not possess 

 the peculiar negative property of being incapable of overcoming 

 resistance; for the whole or any subdivision of it is truly intense 

 and is capable of overcoming great resistance, and of working a 

 telegraph at great distances. It seems to me that the reinforce- 

 ment of an intensity current, by the addition of another of the 

 satne quality, has the effect of increasing the volume, and not of 

 converting it in any proper sense into a quantity current. It, 

 therefore, seems to merit an appropriate name to distinguish it. 



. Theoretically, as stated by authors, the increasing of the number 

 of cups in compound battery increases the intensity nearly in pro- 

 portion to the number of cups, while the quantity is not increased. 

 And, on the other hand, by increasing the number arranged in 

 simple battery, the intensity is increased but little, while the 

 quantity is increased nearly in proportion to the number of cups. 



By testings made by myself, with four cups of Hill's, battery, 



