If a message is to be sent at night, the Ardois system of night signals, with which all our vessels carrying an electric plant are fitted, is employed. These signals consist essentially of five groups of double lamps, the two lamps in each group containing incandescent electric lamps, and showing white and red respectively. By the combination of these lights letters can be formed, and so, letter by letter, a word, and hence an order, can be spelled out for the guidance of the ships of the squadron. These lamps are suspended on a stay in the rigging, and are worked by a keyboard from the upper bridge.
On the smaller ships of the service, those which are not fitted with electric lighting, Very’s night signals are used. This set includes the implements for firing and recharging the signals.
The latter show green and red stars on being projected from pistols made for them. The combination in various ways is used to express the numbers from one to nine and cipher, so that the numbers, to four digits, contained in the [pg 378]signal-book, may be displayed. The Myer wigwag system is employed either by day or by night. Flags and torches are employed. The official flag is a red field with a small white square in the centre; the unofficial flag is the same with the colours reversed. The operator, having attracted the attention of the ship which is to be signalled by waving the flag or torch from right to left, transmits his message by motions right, left, and front, each motion the element of a letter of the alphabet, the letter being made up of from one to four motions.
When circumstances permit, the heliograph is sometimes used. The rays of the sun are thrown by a system of mirrors to the point with which it is desired to communicate, and then interrupted by means of a shutter, making dots and dashes as used in the Morse telegraph code. This system is used only when operations ashore are going on, as the rolling of the ship would prevent the concentration of the sun’s rays.
The present systems of flag signalling are products of experience in the past, and are the natural growth of the cruder flag system in use during the War of 1812, and in the Civil War. There have been some changes in the construction of flags, and the scope of communication has been enlarged, but otherwise our forefathers talked at sea in much the same way as we do now. Of course the Ardois light signal is something very modern. In old times they communicated at night either with coloured lights or by torches, and, as there was no alphabetical code in those days, the process was by means of flashes (representing numbers in the signal book), and it was long and tedious.
APPENDIX C.
SANTIAGO DE CUBA.
Santiago is the most easterly city on the southern coast of Cuba, second only to Havana in its strategic and political importance, and is the capital of the eastern department, as well as its most flourishing seaport.