1851 Great Exhibition: Official Catalogue: Class X.: C. V. Walker
430. WALKER, C. V., Tonbridge — Inventor.
Insulation of telegraph wires, exhibited as in situ on a pole-head, and detached on the table. The earthenware cone by which the telegraph wire is suspended, is so shaped that the point of contact with the wire is small, is sheltered, and is far from the pole. The shackle frame used for insulating the wire at winding-posts is glazed iron; and its earthen cylinders are so constructed as to give a great length of insulating material.
Insulation of telegraph wires in tunnels, exhibited as in actual use. The wire is covered with gutta percha by Mr. T. Foster's patent process, and is placed in grooved boards, prepared with varnish, and fixed against the tunnel walls.
[Mr. Forster's process of covering telegraphic wires is as follows:— The gum, after being cleared, is macerated by steam machinery in a heated iron vessel. It is thence transferred, lump by lump, to a pair of heated grooved rollers, between which it is passed and pressed into solid cylinders three or four feet in length. It is now ready for the covering machine to which it is carried, and where it is used while warm and soft. This machine consists of two pair of hollow polished iron flapping rollers, heated, as occasion requires, by steam, and of a pair of small grooved cutting rollers. The cutting rollers vary both in the number and the size of the grooves, according to the character of covering required. The wire employed in the tunnels on the South-Eastern Railway, and which are under the superintendence of Mr. Walker, is No. 16 copper, and is covered by six grooved rollers, six wires being covered at one operation. The diameter of the wire, with its covering, being one-fourth of an inch. The two pairs of flatting rollers are placed one over the other, with a small interval between them. The six wires traverse the interval between the two pairs of flatting rollers, and pass between the six grooved cutting rollers with one of the sheets of gittta percha above them and another below, and appear on the other side as a perfect band of six covered wires. They are pulled apart when single wires are required, or left undisturbed when required in a band.—J. G.]
Moveable studs, fitted to Cooke and Wheatstone's electric telegraph, to counteract deflections of the needle arising from meteorological phenomena. When the needles are deflected by extraneous causes, so as to touch the ivory studs, or stops, the latter are to be moved in the direction of the deflection, until they are again made equidistant.
Compound needle, consisting of several small needles secured on an ivory disc.
Bell transferrer, an ebony cylinder so inlaid with brass and combined with springs as to transfer the telegraph bell to the up or the down side of an intermediate station, according as that station is talking down or up the line.
Let A B C be a telegraph wire of any length, having instruments at A, B and C; B being the intermediate station, and having the bell and the needle on the said wire. If the bell is so connected as to be on the A side [Diagram] of the needle at station B, when B and C are in communication, it is required to transfer it to the C side, when A and B are in communication; so that while B talks to A, with the rest of the line cut off, he can hear if C rings; or while he talks to C, he can hear if A rings.
This effect is produced, by selecting some convenient place inside the instrument for dividing the wires, and placing springs at these spots. These springs, six in number, press, three above and three below, on brass laid in the ebony cylinder, visible on the left side of the instrument.
When the word UP, on the stud in front of the instrument is vertical, the springs are connected in pairs, as 1, 2; 3, 4; 5, 6. When the word UP is horizontal, the springs are connected in pairs, as 1, 4; 5, 3; 2, 6, thus transferring the bell to the other side of the needle.
The same operation that transfers the bell to the C side of B, cuts off the C half of the line, by the other springs not concerned in this description.
Branch double turn-plate, being a box-wood cylinder, so inlaid with brass and combined with springs as to enable a junction station to put a branch line of telegraph in communication with either direction of the main line; and completing a perfect circuit for the other portion of the main line.
Lightning conductors, for telegraph wires, shown in situ as fitted in telegraph offices, and shown on the table in parts.
Graphite battery; a common sand battery, charged with diluted acid, but having the negative plate constructed of slices of corrosion from gas retorts, instead of copper. Such batteries last longer than the others, there being no salt of copper present to produce action on the zinc.
Up and down ringing key, a contrivance for sending the electric force from an intermediate station to ring bells in the required direction only; the apparatus when at rest constituting part of a complete circuit.