<s>
The	O
Clark	B-Algorithm
cell	I-Algorithm
,	O
invented	O
by	O
English	O
engineer	O
Josiah	O
Latimer	O
Clark	O
in	O
1873	O
,	O
is	O
a	O
wet-chemical	O
cell	O
(	O
colloquially	O
:	O
battery	O
)	O
that	O
produces	O
a	O
highly	O
stable	O
voltage	O
.	O
</s>
<s>
In	O
1893	O
,	O
the	O
output	O
of	O
the	O
Clark	B-Algorithm
cell	I-Algorithm
at	O
15	O
°C	O
was	O
defined	O
by	O
the	O
International	O
Electrical	O
Congress	O
as	O
1.434	O
volts	O
,	O
and	O
this	O
definition	O
became	O
law	O
in	O
the	O
United	O
States	O
in	O
1894	O
.	O
</s>
<s>
This	O
definition	O
was	O
later	O
supplanted	O
by	O
one	O
based	O
on	O
the	O
Weston	B-Algorithm
cell	I-Algorithm
.	O
</s>
<s>
Clark	B-Algorithm
cells	I-Algorithm
use	O
a	O
zinc	B-Application
,	O
or	O
zinc	B-Application
amalgam	O
,	O
anode	O
and	O
a	O
mercury	O
cathode	O
in	O
a	O
saturated	O
aqueous	O
solution	O
of	O
zinc	B-Application
sulfate	O
,	O
with	O
a	O
paste	O
of	O
mercurous	O
sulfate	O
as	O
depolarizer	B-Algorithm
.	O
</s>
<s>
Clark	O
's	O
original	O
cell	O
was	O
set	O
up	O
in	O
a	O
glass	O
jar	O
in	O
a	O
similar	O
way	O
to	O
a	O
gravity	O
Daniell	B-Algorithm
cell	I-Algorithm
.	O
</s>
<s>
Above	O
this	O
was	O
the	O
mercurous	O
sulfate	O
paste	O
and	O
,	O
above	O
that	O
,	O
the	O
zinc	B-Application
sulfate	O
solution	O
.	O
</s>
<s>
A	O
short	O
zinc	B-Application
rod	O
dipped	O
into	O
the	O
zinc	B-Application
sulfate	O
solution	O
.	O
</s>
<s>
The	O
zinc	B-Application
rod	O
was	O
supported	O
by	O
a	O
cork	O
with	O
two	O
holes	O
—	O
one	O
for	O
the	O
zinc	B-Application
rod	O
and	O
the	O
other	O
for	O
a	O
glass	O
tube	O
reaching	O
to	O
the	O
bottom	O
of	O
the	O
cell	O
.	O
</s>
<s>
A	O
platinum	B-Operating_System
wire	O
,	O
fused	O
into	O
the	O
glass	O
tube	O
,	O
made	O
contact	O
with	O
the	O
mercury	O
pool	O
.	O
</s>
<s>
It	O
was	O
set	O
up	O
in	O
an	O
H-shaped	O
glass	O
vessel	O
with	O
zinc	B-Application
amalgam	O
in	O
one	O
leg	O
and	O
pure	O
mercury	O
,	O
surmounted	O
by	O
a	O
layer	O
of	O
mercurous	O
sulfate	O
paste	O
,	O
in	O
the	O
other	O
.	O
</s>
<s>
The	O
vessel	O
was	O
filled	O
,	O
nearly	O
to	O
the	O
top	O
,	O
with	O
zinc	B-Application
sulfate	O
solution	O
.	O
</s>
<s>
Electrical	O
connections	O
to	O
the	O
zinc	B-Application
amalgam	O
and	O
the	O
mercury	O
were	O
made	O
by	O
platinum	B-Operating_System
wires	O
fused	O
through	O
the	O
lower	O
ends	O
of	O
the	O
legs	O
.	O
</s>
<s>
The	O
cell	O
yields	O
a	O
reference	O
EMF	O
of	O
1.4328	O
volts	O
at	O
a	O
temperature	O
of	O
15	O
°C	O
(	O
288	O
K	B-Operating_System
)	O
.	O
</s>
<s>
The	O
design	O
had	O
two	O
drawbacksa	O
rather	O
large	O
temperature	O
coefficient	O
of	O
−	O
1.15	O
mV/	O
°C	O
,	O
and	O
corrosion	O
problems	O
caused	O
by	O
the	O
platinum	B-Operating_System
wires	O
alloying	O
with	O
the	O
zinc	B-Application
amalgam	O
connections	O
where	O
they	O
enter	O
the	O
glass	O
envelope	O
.	O
</s>
<s>
In	O
1905	O
,	O
Clark	B-Algorithm
cells	I-Algorithm
were	O
supplanted	O
as	O
a	O
voltage	O
standard	O
by	O
the	O
more	O
temperature-independent	O
Weston	B-Algorithm
cell	I-Algorithm
.	O
</s>
