MODE OF CROSSING BROAD RIVERS, OR OTHER BODIES OF WATER, WITHOUT WIRES._The American Electro Magnetic Telegraph With the Reports of Congress, and a Description of All Telegraphs Known, Employing Electricity or Galvanism

The following extract from Professor Morse’s letter to the Secretary

of the Treasury, and by him submitted to the House of Representatives,

Dec. 23, 1844, in relation to this interesting subject, will

sufficiently illustrate it:

“In the autumn of 1842, at the request of the American Institute, I

undertook to give to the public in New York a demonstration of the

practicability of my telegraph, by connecting Governor’s Island with

Castle Garden, a distance of a mile; and for this purpose I laid my

wires properly insulated beneath the water. I had scarcely begun

to operate, and had received but two or three characters, when my

intentions were frustrated by the accidental destruction of a part

of my conductors by a vessel, which drew them up on her anchor, and

cut them off. In the moments of mortification, I immediately devised,

a plan for avoiding such an accident in future, by so arranging my

wires along the banks of the river as to cause the water itself to

conduct the electricity across. The experiment, however, was deferred

till I arrived in Washington; and on December 16, 1842, I tested my

arrangement across the canal, and with success. The simple fact was

then ascertained, that electricity could be made to cross a river

without other conductors than the water itself; but it was not until

the last autumn that I had the leisure to make a series of experiments

to ascertain the law of its passage. The following diagram will serve

to explain the experiment.

[Illustration: FIG. 31.]

A, B, C, D, are the banks of the river; N, P, are the battery; E is

the electro magnet; _w w_, are the wires along the banks, connecting

with copper plates, _f_, _g_, _h_, _i_, which are placed in the water.

When this arrangement is complete, the electricity, generated by the

battery, passes from the positive pole, P, to the plate _h_, across

the river through the water to plate _i_, and thence around the coil

of the magnet, E, to plate _f_, across the river again to plate _g_,

and thence to the other pole of the battery, N. The numbers 1, 2, 3, 4,

indicate the distance along the bank measured by the number of times of

the distance across the river.

The distance across the canal is 80 feet; on August 24th, the following

were the results of the experiment.

---------------------+-------+--------+------+-------+-------+--------

No. of the | 1st. | 2d. | 3d. | 4th. | 5th. | 6th.

---------------------+-------+--------+------+-------+-------+--------

battery, | 14 | 14 | 14 | 7 | 7 | 7

_w_, _w_, | 400 | 400 | 400 | 400 | 300 | 200

galvanometer, |32 & 24|13½ & 4½| 1 & 1|24 & 13|29 & 21|21½ & 15

_f_, _g_, _h_, _i_, |5 by 2½|16 by 18|6 by 5|5 by 2½|5 by 2½| 5 by 2½

| ft.| in.| in.| ft.| ft.| ft.

---------------------+-------+--------+------+-------+-------+--------

Showing that electricity crosses the river, and _in quantity in

proportion to the size of the plates in the water._ The _distance

of the plates on the same side_ of the river _from each other_ also

affects the result. Having ascertained the general fact, I was desirous

of discovering the best practical distance at which to place my copper

plates, and not having the leisure myself, I requested my friend

Professor Gale to make the experiments for me. I subjoin his letter and

the results.

NEW YORK, _November_ 5th, 1844.

MY DEAR SIR—I send you, herewith, a copy of

a series of results, obtained with four different sized

plates, as conductors to be used in crossing rivers. The

batteries used were six cups of your smallest size, and

one liquid used for the same throughout. I made several

other series of experiments, but these I most rely on for

uniformity and accuracy. You will see, from inspecting the

table, that the distance along the shores should be _three

times greater_ than that from shore to shore across the

stream; at least, that four times the distance does not

give any increase of power. I intend to repeat all these

experiments under more favorable circumstances, and will

communicate to you the results.

Very respectfully,

L. D. GALE.

Professor S. F. B. MORSE,

_Superintendent of Telegraphs_.

Series of Experiments on four different sizes of plates,

to wit: 1st, 56 square inches; 2d, 28 square inches; 3d,

14 square inches; and 4th, 7 square inches.

_Experiment 1st.—Surface of one face of the copper plate,

56 square inches; battery, Morse’s

smallest, 6 cups._

NOTE.—In all the experiments,

_f_ and _g_ are stationary.

--------+--------+---------+---------+------+------+------+------

bank | along | 1st | 2d | 3d | 4th | 5th | 6th

--------+--------+---------+---------+------+------+------+------

1 | 1 | 22° | 23° | 23° | 22° | 22° | 22°

--------+--------+---------+---------+------+------+------+-------

1 | 2 | 31 | 32 | 31½ | 31 | 31 | 31

--------+--------+---------+---------+------+------+------+-------

1 | 3 | 36 | 36 | 35½ | 35 | 35 | 35

--------+--------+---------+---------+------+------+------+-------

1 | 4 | 36 scant| 36 scant| 34½ | 34 | 34 | 34

--------+--------+---------+---------+------+------+------+-------

_Experiment 2d.--Plates 28 square inches,

conducted as above._

--------+--------+-------+-------+-------+-------+----------+-------

bank | along | 1st | 2d | 3d | 4th | 5th | 6th

--------+--------+-------+-------+-------+-------+----------+-------

1 | 1 | 18° | 17° | 17° | 17° | 17° | 17°

--------+--------+-------+-------+-------+-------+----------+-------

1 | 2 | 27 | 26 | 27½ | 27½ | 27½ | 27

--------+--------+-------+-------+-------+-------+----------+-------

1 | 3 | 31 | 31 | 31 | 31 | 31 | 31

--------+--------+-------+-------+-------+-------+----------+-------

1 | 4 | 31 | 31 | 31 | 31 | 31 scant.| 31

--------+--------+-------+-------+-------+-------+----------+-------

_Experiment 3d.--Plates 14 square inches,

conducted as No. 1._

-------------+-----------+------+------+------+------+------+------

Distance from| Distance | 1st | 2d | 3d | 4th | 5th | 6th

-------------+-----------+------+------+------+------+------+------

1 | 1 | 8° | 8½° | 8½ | 8° | 8° | 8°

1 | 2 | 19½ | 20 | 19½ | 19 | 19 | 19

1 | 3 | 23½ | 23½ | 23½ | 23½ | 23½ | 23½

1 | 4 | 24½ | 24½ | 23½ | 23½ | 23½ | 23½

-------------+-----------+------+------+------+------+------+------

_Experiment 4th.--Plates 7 square inches,

conducted as No. 1._

-------------+-----------+------+------+------+------+------+------

Distance from| Distance | 1st | 2d | 3d | 4th | 5th | 6th

-------------+-----------+------+------+------+------+------+------

1 | 1 | 5° | 5° | 5° | 5° | 3° | 3°

1 | 2 | 15 | 14½ | 14 | 15 | 15 | 12

1 | 3 | 17½ | 18 | 17½ | 17½ | 18 | 17

1 | 4 | 18 | 18 | 18 | 17½ | 17½ | 17

-------------+-----------+------+------+------+------+------+------

The distance from bank to bank, 30 inches. Depth of water,

12 inches. In experiment 4, the liquor of the batteries was

very weak, exhausted towards the last; and in trials 5 and

6, the irregularities are to be attributed in part to the

weak liquor, and in part to the twilight hour at which the

experiments were made.

As the result of these experiments, it would seem that there may

be situations in which the arrangements I have made for passing

electricity across the rivers may be useful, although experience alone

can determine whether lofty spars, on which the wires may be suspended,

erected in the rivers, may not be deemed the most practical. The

experiments made were but for a short distance; in which, however, the

principle was fully proved to be correct. It has been applied under the

direction of my able assistants, Messrs. Vail and Rogers, across the

Susquehanna river, at Havre-de-Grace, with complete success; a distance

of nearly a mile.

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