198 
IOWA ACADEMY OF SCIENCES. 
ampere and remained perfectly constant during the remain- 
ing time. This cell was allowed to run for three days 
longer. Its E. M. F. lowered slightly but was still .67 volt 
at the end of a four days 7 run. The cell delivered during 
that time about 80 ampere hours of electricity. At the 
end of four days its internal resistance w x as .04 ohm. 
All three cells gave a voltage of .95 on open circuit 
before being used. All of them recovered to .8 volt inside 
of fifteen seconds w T hen the circuit was broken after a 
twenty-four hour run. The Edison showed a higher effi- 
ciency than the Gordon. This, I think, is due to the fact 
that the copper oxide in the Gordon is rather loosely packed 
preventing as high a conductivity as the closely compressed 
plates of the Edison. The Edison was 150 ampere hour 
cell of the Q type and weighed seven and one-half pounds. 
The Gordon was the commercial 300 ampere hour cell and 
weighed fifteen pounds. The sheet steel cell was about the 
size of a pint measure and weighed about two and one-half 
pounds. Enough copper oxide was compressed into its 
netting to give it a capacity of 160 ampere hours for two 
discharges using the same zinc and but one renewal of the 
electrolyte. 
The advantage of such a light sheet steel cell of high 
capacity is evident. It can be produced at less price than 
the Daniell. The container can not be broken. The lid 
can be sealed so as to prevent any spilling of the electro- 
lyte. The cell is always ready for use. Local action in 
the cell is very small when the chemicals are compara- 
tively pure. When working on low external resistance 
the wattage is always higher than that of a Daniell 
operating under similar conditions. 
A very convenient thing about the cell, however, is its 
reversibility. When the capacity of the cell is exhausted 
as a primary, an amalgamated brass gauze electrode is sub- 
stituted for storage purposes. When storing, the zinc is 
deposited on the amalgamated gauze and the reduced cop- 
per is converted into an oxide. 
It is true that the two principal defects of the alkaline 
copper cell are first, that the zinc can not be deposited in 
