698 
lower row of blocks marked 2 are connected 
to the negative lead of the same outlet. 
And so on with the blocks marked 3. It 
will be noticed that one of the two above- 
mentioned N blocks is located in the same 
row with the P blocks, and this N block of 
one cell is adjacent to a P block of its 
neighbor. This is for the purpose of con- 
necting cells in series. 
“Hor instance, suppose that the operator 
at outlet No. 2 wanted to use cells B, C and 
D in series, he would connect the P block 
SCIENCE. 
[N.S. Von. XIII. No. 331. 
110-volt lighting circuit by means of a 
small knife switch, conveniently located at 
the side of the operating table. Incandes- 
cent lamps placed in this charging circuit 
kept the current down to the desired value. 
The cells were then all connected in series 
and across the No. 1 leads. Making No. 1 
leads the charging circuit also provided 
means for using the 110-volt current for 
electrolytic work where the solutions were 
of such high resistance that the twelve 
cells in series were insufficient to produce 
Fic. 1. Old Working Table. 
of cell B to 2, the P block of C to the N of 
B, and the P block of D to the N block of 
C, finally connecting the N block of D to 
its adjacent 2 block. 
“Tn addition to the above, the operator 
at 3 could insert plugs so as to use the cells 
HK, F, G, H, I, J in a combination of all in 
parallel, three in parallel two in series, two 
in parallel three in series, or all in series, 
just as occasion might demand. 
“The cells were charged (generally at 
night) by connecting circuit No. 1 to the 
the desired results. Portable resistance 
frames were provided, consisting of wooden 
frames mounted on neat iron feet, having 
German-silver wire coils stretched between 
brass blocks on both sides. There were 
sixteen pairs of coils of one resistance, and 
ten pairs of one-tenth of that resistance, 
all joined in series between two binding 
posts, and so arranged that any number of 
coils of either denomination could be short- 
circuited by means of two plugs ; thus the 
resistance could be altered by small steps. 
