NIGHT SIGNAL LAMPS.
In a report to the Trustees for improving the Queensferry passage, made in 1811, Mr. Stevenson proposes a set of signals as described in the following extract, his proposal being, in fact, the signal now in use on all British railways:—
“Upon the supposition of its being the intention of this Honourable Trust to have an establishment on the south side of the Firth similar to that which is now proposed for the north side, the reporter takes the liberty of observing that much advantage, as the Trustees know, might be derived by the public from a few simple and well appointed signals, both for night and day.
“Those intended for the day may be constructed upon a modified scale, after the common telegraphic method; while the night signals can be rendered extremely simple and effective by interposing at pleasure between the observer and the reflector a shade of coloured glass. By connecting these partial obscurations of colouring the light with an index that shall be understood on both sides of the passage, orders may be communicated in a very expeditious manner.”