A CONVENIENT VOLTAIC CELL. 
BY L. BEGEMAN. 
I wish to discuss briefly a convenient form of the Lalande 
class of voltaic cells for which the government has recently 
allowed me a patent. While the cell possesses nothing 
startling in its newness, it yet has those advantages which 
make it better, I think, than any other for the purpose for 
which it was devised. 
The old Lalande-Chaperon primary cell consisted of a 
steel jar with a sealed top from w T hich was suspended a 
coiled rod of zinc. The electrolyte was either caustic soda 
or potash, and the depolarizer was copper oxide, a thick 
layer of which was placed in a copper pan resting on the 
bottom of the container. The cell was remarkable for its 
great capacity, but defective in that the depolarizer was not 
in firm contact with the positive electrode which resulted in 
a comparatively high internal resistance and a sluggish 
depolarization. 
The well known Edison primary is a modified Lalande 
in which this defect is overcome by compressing the cop- 
per oxide into firm plates that serve both as depolarizer 
and positive electrode. 
The Gordon is another familiar form of this class of cells. 
While it is true that the Edison and Gordon primaries are 
probably the best cells on the market for all purposes, yet 
their great cost almost prohibits them for general student 
use in the physical laboratory. Many experiments devised 
for students in secondary work demand a cell that delivers 
a constant current. The only primary cells that are 
capable of delivering a constant current for a period of 
time are those of the Lalande or Daniell class. 
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