IMPROVEMENTS IN UNDERGROUND TELEGRAPH LINES
Year: 1878

page_text: LETTERS PATENT to James Smith Pierson, of Brooklyn, in the State of New
York, United States of America, for the Invention of "IMPROVEMENTS IN
UNDERGROUND TELEGRAPH LINES."
PROVISIONAL SPECIFICATION left by the said James Smith Pierson at the
Office of the Commissioners of Patents on the 30th December 1878.
JAMES SMITH PIERSON, of Brooklyn, in the State of New York, United States
of America. "IMPROVEMENTS IN UNDERGROUND TELEGRAPH LINES."
I make use of strips of wood or boards that are channeled in the upper surfaces
with grooves that are parallel or nearly so, and slightly larger than the telegraph
wires or other electric conductors that are to be employed. These grooved boards
are to be laid lengthwise, and the wires introduced into the grooves, and such
grooves are thoroughly filled with bitumen or asphalt, and the board sufficiently
coated to form a bed for the next layer of grooved boards that receive other
telegraph lines or conductors.
In this manner any desired number of telegraph wires or lines can be insulated
and preserved from contact one with the other.
I remark that the asphalt or bituminous material must be of a durable and
slightly yielding quality so that it will not crack, and it must be also adapted to
act as an insulator.
The native asphalt with impurities removed is preferable, and a small quantity
of paraffin may also be employed with the asphalt,

page_text: The grooved strips or boards should be carefully laid so that the joints of the
various layers come at different places, and they should be held firmly together.
For this purpose it is preferable to place them in a case, and entirely fill the same
with the asphalt below, at the sides and above the top layer of grooved planks so as
to keep the parts firmly in place and entirely exclude moisture. The boards may
be clamped together or bound by wires or hoop iron, and the case may be of any
suitable material, such as iron, cement, or wood. If cement or masonry is used the
same is laid below at the sides and above the layers of boards and asphalt as
aforesaid, and when the case is made of sections they should be put together with
tongues and grooves or slip joints that are thoroughly filled with bitumen.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said James Smith Pierson in the Great Seal Patent Office on the 28th June 1879.
JAMES SMITH PIERSON, of Brooklyn, in the State of New York, United
States of America. "IMPROVEMENTS IN UNDERGROUND TELEGRAPH LINES."
I make use of strips of wood or boards that are channeled in the upper surfaces
with grooves that are parallel or nearly so, and slightly larger than the telegraph
wires or other electric conductors that are to be employed. These grooved boards
are to be laid lengthwise and the wires introduced into the grooves, and such
grooves are thoroughly filled with bitumen or asphalt, and the board sufficiently
coated to form a bed for the next layer of grooved boards that receive other
telegraph lines or conductors.
In this manner any desired number of telegraph wires or lines can be insulated
and preserved from contact one with the other.
I remark that the bituminous material must be of a durable and slightly yielding
quality so that it will not crack, and it must also be adapted to act as an insulator.
The native asphalt with impurities removed is preferable, and a small quantity of
parafine may also be employed with the asphalt.
The grooved strips or boards should be carefully laid so that the joints of the
various layers come at different places, and they should be held firmly together.
For this purpose it is preferable to place them in a case, and entirely fill the same
with the asphalt below, at the sides and above the top layer of grooved planks so
as to keep the parts firmly in place and entirely exclude moisture. The boards
may be clamped together or bound by wires or hoop iron, and the case may be
of any suitable material, such as iron, cement, or wood. If cement or masonry
is used the same is laid below at the sides and above the layers of boards and
asphalt as aforesaid, and when the case is made of sections they should be put
together with tongues and grooves or slip joints that are thoroughly filled with
bitumen.
In the Drawing,-
Fig. 1 is a cross section of the lines and the closing case; and
Fig. 2 is a plan partially in section of the case and lines.
The telegraph wires or conductors a are of copper or other material, and the size
of the underground structure will depend upon the number of conductors. The
case b is either of wood, metal, or earthenware. I prefer to make the same of wood
thoroughly coated with asphalt. The sections or lengths of case are united by
tongues and grooves at e, and india rubber, asphalt, or other yielding material is
to be inserted to keep out water, and with metal cases this yields to expansion or
contraction from heat or cold. The cover fis preferably secured by screws.
A layer of melted native asphalt or bitumen is laid in the case b, and upon this
a plank or board h having numerous grooves in its upper surface, and into these
grooves the conductors a are laid.
It is generally best to supply these telegraph wires from reels that are drawn
along the top edge of the pipe or case b, and planks or boards h are laid successively
upon the bitumen, the grooves matching each other. Melted bitumen or asphalt is
poured upon the boards h, and in sufficient quantity to fill the grooves and prevent
moisture reaching either the board or the conductors.
A second board is laid upon the asphalt while hot, and pressure is applied,
sufficient to cause an intimate contact between the board and the bitumen.
The grooved boards should be laid so that the joints of one layer come near the
middle of the boards of the next layer.
A second range of wires is laid in the grooves in the surfaces of the second
layer of the boards I, and the filling in of melted bitumen is made use of as before
described.

page_text: In this manner several layers are introduced in the case, and then the cover is
put on and fastened down if desired.
The bitumen being indestructible, entirely water proof, and slightly elastic, is
excellently, adapted to the insulation and protection of underground telegraph lines,
and the risk of injuries is lessened in consequence of the slight elasticity of the
bitumen, because the same will yield and not crack by the settling of the earth or
the frost displacing the case containing the conductors.
It is to be understood that it is preferable not to employ the inferior or brittle
quality of bitumen or asphalt.
Lateral branches are taken off in the manner represented in Fig. 2, the wires
being laid in transverse grooves that correspond to the grooves in the planks
that pass off laterally, so that the wires can be bent at right angles and laid in the
grooves.
Having now described the nature of my said Invention, and in what manner the
same is or may be carried into effect, I declare that
I claim as my Invention,-
In combination with grooved planks or boards and the conductors in such
grooves, a filling of asphalt introduced into such grooves and around the boards,
substantially as set forth.
In witness whereof, I, the said James Smith Pierson, have hereunto set my
hand and seal, this Sixth day of June, A.D. 1879.
Witnesses,
JAMES SMITH PIERSON. (L.S.)
CHAS. H. SMITH, 140, Nassau St., N.Y.
WILLIAM G. MOTT, 140, Nassau St., N.Y: