Telegraph Batteries
Excerpted from the Telephone and Telegraph Engineers' Pocketbook,
published by International Correspondence Schools, Scranton, PA.
(1908), pages 160 - 166:
Name: Bichromate Grenet, or Poggendorff
Anode: Zinc
Electrolyte: Sulphuric acid, 4 parts; potassium or sodium
bichromate, 3 parts; water, 18 parts;
_or_
Chromic acid, 6 oz.; water, 5 1/2 pt.;
sulphuric acid, 1/2 pt.
Cathode: Carbon
Depolarizer: Potassium bichromate; _or_ sodium bichromate;
_or_ chromic acid
EMF Volts: 1.9 to 2.1
Remarks: Suitable for closed-circuit work. Electrodes
should be removed from solution when not in
use
-------------
Name: Fuller
Anode: Zinc; in porous cup containing 6 oz. of zinc
sulphate to 1 pint of water and a few drops
of mercury
Electrolyte: Sulphuric acid, 17 oz.; water 56 oz.; sodium
bichromate, 6 oz.; placed in jar containing
carbon element
Cathode: Carbon; placed in jar containing electrolyte
Depolarizer: Sodium bichromate
EMF Volts: 2.14
Remarks: Suitable for closed- or open-circuit work.
Elements need not be removed from solution
when cell is not in use
-------------
Name: Bunsen
Anode: Zinc; in jar containing sulphuric acid
solution
Electrolyte: Sulphuric acid, 1 part; water, 20 parts;
specific gravity of solution should be
about 1.09
Cathode: Carbon; placed in porous cup containing
depolarizer
Depolarizer: Nitric acid, specific gravity about
1.33 to 1.4
EMF Volts: 1.89
Remarks: Suitable for closed-circuit work. Gives
off disagreeable fumes. Elements should
be removed from solution when not in use.
-------------
Name: Partz
Anode; Zinc; hung from the lid of the cell
Electrolyte: Sodium chloride; _or_ Magnesium sulphate
(being lighter, this solution floats on
top of the depolarizer
Cathode: Carbon; plate slightly raised from bottom
of jar
Depolarizer: Bichromate solution; _or_ sulpho-chromic
salt solution
EMF Volts: 1.9 to 2
Remarks: Solutions kept apart by the different
specific gravities. Resistance: with
sodium chloride about .5 ohm; with
magnesium sulphate, about 1 ohm
-------------
Name: Pabst
Anode: Wrought Iron
Electrolyte: Ferric chloride
Cathode: Carbon
Depolarizer:
EMF Volts: 0.78
Remarks: Non-polarizing electrolyte
-------------
Name: Daniell
Anode: Zinc; in porous cup containing electrolyte
Electrolyte: Zinc sulphate
Cathode: Copper; surrounded by depolarizer
Depolarizer: Saturated copper sulphate solution and
crystals
EMF Volts: 1.07
Remarks: For closed-circuit work. Electrolyte and
depolarizer kept apart by porous cup
-------------
Name: Daniell, gravity, or Crowfoot cell
Anode: Zinc, held in top part of jar
Electrolyte: Zinc sulphate; specific gravity
not to exceed 1.15; being lighter,
floats on top of copper sulphate
solution
Cathode: Copper; sheet star-shaped, placed
bottom of jar surrounded by de-polarizer
Depolarizer: Saturated copper-sulphate solution and
crystals. 3 pounds of copper-sulphate
crystals for one cell.
EMF Volts: 1.07
Remarks: Solutions kept apart by their different
specific gravities. For closed-circuit
work only. Most economic output is 1/4
ampere. Average resistance, about 3 ohms.
-------------
Name: Leclanche and some dry cells
Anode: Zinc
Electrolyte: Ammonium chloride (sal ammoniac) 3 oz. to
1 pt. water
Cathode: Carbon; usually placed with depolarizer in
porous cup; _or_ Carbon forms porous cup
containing depolarizer
Depolarizer: Dioxide of manganese, sometimes mixed with
broken coke
EMF Volts: 1.3 to 1.7
Remarks: Suitable only for open-circuit work.
Internal resistance, from .4 to 4 ohms
-------------
Name: Edison-Lalande
Anode: Zinc; plate held between two cathode plates
Electrolyte: Caustic potash. 15 per cent. of silicate of
soda said to nearly double capacity of cell
Cathode: Molded plates of cupric oxide; held in copper
frames
Depolarizer: Cupric oxide
EMF Volts: 0.7
Remarks: Electrolyte must be covered with mineral oil.
Suitable for closed-circuit work. Internal
resistance very low
-------------
Name: Harrison
Anode: Zinc; must be amalgamated
Electrolyte: Dilute sulphuric acid, or bisulphate of
potassium, or sodium; must be pure to avoid
local action
Cathode: Lead
Depolarizer: Peroxide of lead; compressed around a
conductor of hard lead
EMF Volts: 2.5
Remarks: Local action is very likely to cause trouble
-------------
[Three other types of cell are listed: Latimer-Clark,
Carhart-Clark, and Weston. These cells are
characterized by EMF values from 1.4333 to 1.0187,
and were used as voltage standards, since their
temperature coefficients of EMF were very stable
or at least predictable. Remember the Weston cell
from freshman physics lab?]
-------------
Excerpt from the general discussion of Primary Batteries,
re Depolarizers:
... The chemical action incident to the generation
of the current consumes the zinc and, in the simplest
cell, liberates hydrogen at the cathode, which tends
to adhere to the surface and reduces the EMF of the
cell. To overcome this effect of polarization, a
depolarizer is often used, which will dispose of the
hydrogen as fast as it is formed......
----------------------------------------
second file:
-----------------------------
excerpted from the Telephone and Telegraph Engineers' Pocketbook,
published by International Correspondence Schools, Scranton, PA.
(1908):
Following a listing of 15 types of primary cells, with
all their characteristics, we find:
Directions for Setting up the Crowfoot Gravity Cell.
Proceed as follows: Unfold the copper strip so as to
form a star and place it in the bottom of the jar. The
point where the copper connecting wire is riveted to the
copper electrode should be near the bottom of the cell,
and the insulated covering on the wire should come close
to the riveted joint. Suspend the zinc about 4 in. above
the copper by hooking the lug on the side of the jar. The
method of suspending other forms of zincs will be evident
from their construction. Pour sufficient clean water into
the jar to cover the zinc and drop about 3 lb. of copper
sulphate in a cell to be used for heavy, continuous work --
for instance, for the local-circuit batteries that run
telegraph sounders; for the batteries in a main-line
telegraph circuit, a smaller charge will be sufficient,
and, in quadruplex-telegraph circuits, the so-called
"long" end of the battery will need less bluestone than
the "short" end, because the former is not worked as
continuously as the latter. The internal resistance
may be reduced and the battery made immediately available
by drawing about 1/2 pt. of solution of sulphate of zinc
from a battery already in use, and pouring it gently into
the jar; or, when this cannot be done, by pouring carefully
on top of the solution in the jar 4 or 5 oz. of pulverized
sulphate of zinc previously dissolved in a cup of water.
If there is no hurry for the cells, do not put in the zincs
until the solutions have had time to settle to their normal
conditions, which will require at least 24 hr. This
prevents or reduces the formation of a black deposit on the
zinc. When there is much of this black deposit, remove the
zinc and brush or scrape it off. If no zinc sulphate is
added in setting up the cell, it will be necessary to short-
circuit the cell for some time (24 hr. will not be too long)
before it will be in good condition.
(From the previously-mentioned listing, we find the Daniell
cell's characteristics to be:
Name: Daniell, gravity, or Crowfoot cell
Anode: Zinc, held in top part of jar
Electrolyte: Zinc sulphate; specific gravity
not to exceed 1.15; being lighter,
floats on top of copper sulphate
solution
Cathode: Copper; sheet star-shaped, placed
bottom of jar surrounded by de-polarizer
Depolarizer: Saturated copper-sulphate solution and
crystals. 3 pounds of copper-sulphate
crystals for one cell.
EMF Volts: 1.07
Remarks: Solutions kept apart by their different
specific gravities. For closed-circuit
work only. Most economic output is 1/4
ampere. Average resistance, about 3 ohms.
-------------------------------------
QSY to Morse Telegraph Miscellaneous
QSY to Telegraph Lore Home Page