May 3, 1901.] 
A third plug was provided to prevent the 
necessity for opening the circuit when al- 
tering the resistance. The measuring in- 
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struments were portable, Weston’s and 
Hartman-Braun. This entire electrical 
equipment was fairly satisfactory and was 
SCIENCE. 
699 
duplicated later. It had many defects; 
for instance, it was possible to connect cells 
in parallel and series at the same time and 
the student sometimes preferred to make 
connections haphazard rather than work 
out and understand the whole scheme. 
And even though he did understand it, the 
chances for making a wrong connection 
were too great because of the confusingly 
large number of blocks on the boards. 
The resistance frames had the fault that 
the German-silver wire soon became so 
corroded as to break. Replacing the coils 
by tinned steel wire proved to be little or 
no improvement. The portable instru- 
ments, too, were in danger of being injured 
by solutions being spilled on them, and 
sometimes received rather rough handling, 
which soon decreased their usefulness. 
“ For these reasons, and the growing de- 
mand for training in electrochemistry, it 
was finally decided to provide a laboratory 
and installation sufficient to accommodate 
eighteen students. The effort was also 
made to overcome as fully as possible the 
defects of the previous arrangement. It 
will readily be seen that the matter of com- 
plication would be made indefinitely worse 
if the number of outlets were increased to 
eighteen and the number of cells to fifty, so 
an entirely different arrangement of switch- 
board had to be devised. The only room 
available was one fifteen feet by twenty-six 
feet, as shown in Fig. 3, and it soon became 
evident that this room would not accom- 
modate more than sixteen students, allow- 
ing each individual three feet by twenty 
inches of table space. 
“‘ Storage cells were, because of their con- 
stanecy, decided upon for this installation. 
Those in use have 120 ampére hours’ ea- 
pacity, with a normal discharge rate of 15 
amperes and a maximum rate of 30 ampéres. 
Two groups of twenty-four cells each were 
located in the compartments shown; they 
supply their respective sides of the room. 
