* 
118 Contributions to Electricity and Magnetism. 
another communication. After considerable delay, occasioned by 
alterations in the rooms of the physical department of the col- 
lege, I was enabled to resume my researches, and since then I 
have been so fortunate as to discover a series of new facts belong- 
ing to different parts of the general subject of my contributions. 
Those Tw announced to the Society at different times, as they 
were di red, and I now purpose to select from the whole such 
portions as relate particularly to the principal subject of my last 
paper, namely, the induction at the beginning and ending of a 
galvanic current, and to present them as a continuation, and, in 
a measure, as the completion, of this part of my researches. The 
other results of my labors in this line will be arranged for publi- 
cation as soon as my duties will permit me to give them a more 
careful examination. 
2. In the course of the experiments I am about to describe, I 
have had occasion to repeat and vary those given in my last pa- 
per, and Tam happy to be able to state, in reference to the results, 
that, except in some minor particulars, which will be mentioned 
in the course of this paper, I have found no cause to desire a 
change in the accounts before published. My views, however, 
of the connection of the phenomena have been considerably mod- 
ified, and I think rendered much more definite by the additional 
light which the new facts have afforded. 
3. The principal articles of apparatus used in these experiments 
are nearly the same as those described in my last paper, namely, 
several flat coils and a number of long wire helices. (III, 6, 7; 
8.)* Ihave, however, added to these a constant battery, on Pro- 
fessor Daniell’s plan, the performance of which has fully answered 
my expectations, and confirmed the accounts given of this form 
of the in strument by its author. It consists of thirty elements, 
formed of as many copper cylinders, open at the bottom, each 
five inches and 
nd a half in height, three inches and a half in diam- 
eter, and placed in eart en cups. A zine rod is suspended in each 
of these of the same length as the nders, and about one inch | 
in diam er. The several ele x ents are connected by a thick cop 
per wire, soldered. to the copper eylin | “6 one element, and dip- 
.. Ping into a cup‘of mercury on the zin ‘the: next. The cop 
ay 
‘numerals IT or III are included in th > parenthesis, reference is made 
i ka contributions, 3 “ we 
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