-----------------------+--------------+------------------+---------
| | Resistance |
No. of cell. | Battery. | "gold | "gold | Ratio
| | anode."|cathode."|
-----------------------+--------------+--------+---------+---------
| | ohms. | ohms. |
3/8 inch square. No. 4 | 5 elements. | 20,000 | 1,000 | 20 to 1
" " " 3 | Se. cell. | 6,500 | 400 | 16.2 "
Full size, No. 13 | 1 element. | 9,000 | 800 | 11.2 "
" " " 14 | 5 " | 2,440 | 130 | 18 "
" " " 15 | 5 " | 4,640 | 210 | 22 "
" " " 27 | 5 " | 6,900 | 440 | 16 "
" " " 126 | 1 " | 5,000 | 330 | 15 "
-----------------------+--------------+--------+---------+---------
The direction of the current is always indicated by stating the position
of the gold electrode, by the terms "gold anode" and "gold cathode." The
above measurements were made in dark.
4. _Sensitiveness to change of battery power_.--My cells are extremely
sensitive to any change in the strength or character of the current
flowing through them, which is shown by a corresponding change in the
resistance of the cell. I can, therefore, vary the resistance of one of
my cells in many ways, and the following may be specified--
(a) By changing the potential or electromotive force of the current
through the cell.
(b) By changing the "quantity" of the battery or current.
(c) By putting more or less resistance in the circuit.
(d) By dividing the current, by one or more branch circuits or shunts
around the cell.
(e) By varying the resistance in any or all of said circuits.
A cell whose resistance becomes greater as the battery power becomes
greater, and _vice versa_, I call an "L B cell" signifying _Like the
Battery power_. A "U B cell" is one whose resistance becomes greater as
the battery power (or strength of current) becomes less, and _vice
versa_, being _Unlike the Battery power_, or current strength.
These changes of resistance are not due to heating of the conductor or
the selenium, and the following instance will illustrate this. I have one
cell in which the selenium has about one-fourth inch square of surface
melted on a brass block one inch thick. This cell measured, with 25
elements of Leclanche, 40,000 ohms. On changing the battery to 5 elements
the resistance fell instantly to 30 ohms, and there remained. On again
using the current from 25 elements, the resistance instantly returned to
40,000 ohms. Had these results been due in any degree to heating, the
resistance would have changed gradually as the heat became communicated
to the brass, whereas no such change occurred, the resistances being
absolutely steady. Moreover, even the fusion of the selenium would not
produce any such change.
The "U B" property does not ordinarily change the resistance of the cell
to exceed ten times, i.e., the resistance with a weak current will not be
over ten times as high as with a strong one. But I have developed the "L
B" property to a far higher degree. Table C gives some recent results
obtained with L B cells, including one whose resistance, with 25 elements
Leclanche, was 11,381 times as high as with 8 elements, and which, after
standing steadily at 123 ohms (and then at 325 ohms with 1 element), on
receiving the current from 25 elements again returned to its previous
figure of 1,400,000 ohms.