Although this particular review covers the pre-radio limitations of maritime signalling within Great Britain, at this time the same basic problems were being encountered world-wide.
Journal of the Society of Telegraph Engineers, 1872, pages 410-413:



By  Captain  P.  COLUMB,  R.N.

THE disaster which occurred to the "Northfleet" has directed public attention to the question of signals of distress--especially by night--amongst merchant ships. It has been somewhat startling to the general public to learn that a ship and all on board her may be destroyed within immediate reach of assistance, and in the midst of friends, without having the power to convey the intelligence to one of them, while the time for doing so might have been ample if only the means had been provided.
    Though the question is new to the public, it is very old to those who have watched the progress of these events, and it is by no means new to the Board of Trade. That department has had the question thrust upon it, not only by circumstances similar to those of the "Northfleet," but by the converse case, where a loss of life occurred in the attempt to carry succour to a ship which was not really in want of that particular kind of help.
    It is comparatively common for ships to be destroyed or injured in various ways from want of power--at night or in fog--of asking either advice or assistance. But it is, perhaps, more common for life and property to suffer from want of means of telegraphing after the disaster to the ship has occurred. A very notable instance was presented by the Rangoon, which ran on a rock near Point de Galle, and whose signals, meant to express that she was sinking, really conveyed to the minds of the observers the idea that she was speeding some parting guests.
    That such a state of things should now exist, is hardly creditable to modern science, but perhaps one excuse may be found in the thought that the facts are not generally known to men who might devote themselves to supplying the deficiency.
    At present, ships of the mercantile marine carry, as a rule, the means of making any want, whatever its nature, known to neighbouring vessels or to signal stations on shore, so long as daylight and clear weather lasts. But at night or in fog, when the necessity for such power presses with double force, they are absolutely precluded from expressing their wants. At this moment such ships are accustomed to use "flare up lights," rockets, blue lights, or even guns, quite indifferently, to express by night all their various wants and distresses, from want of a pilot, or a tug, up to the want of such immediate assistance for the saving of life as was called for in the case of the "Northfleet."
    The natural consequence has ensued, that when these signals are seen, only those whose livelihood is gathered by supplying pilotage or steam power, approach the ships making them, and life or property is lost for the want of the particular help required, which is perhaps quite close at hand.
    In the Royal Navy these guns, rockets, and blue lights, are also in constant use, but they bear no more signification than they ought to bear. That is, they simply draw attention to the ship which uses them. All sudden wants or distresses are denoted at night, or in fog, side by side with these alarm or attention signals, in words. If a man of war catches fire, and requires the help of her fellows, she says she is on fire and specifies the sort of help she wants. If she is running into danger unwittingly, her fellows tell her of the danger and how to avoid it. If, like the "Northfleet," she is sinking, surrounded by friends, she tells the state of her case, and asks that boats may be sent to save life.
    It is generally supposed that the difficulty in the Mercantile Marine will be met by legislation which shall devise a particular signal denoting "urgent distress," and then, by making its use on trivial occasions a punishable offence, secure that it shall show every observer that urgent distress is suffered by the vessel employing it. But if this idea be examined somewhat closely, it will be found at best to be but a very doubtful remedy for the present evil.
    In the first place there is something incongruous in applying compulsory legislation to what is, after all, a scientific question. If legislative sanction is required to encourage the use of a new process, instrument, or substance, of which the value is only known to experts, it seems a very legitimate function of Government to give the new thing that much support; and science suffers in no degree from such help. When, however, the new thing is intended to be useful to him who uses it, it almost seems a hindrance to scientific progress for a Government to exercise any power beyond sanctioning its employment, and if a general rule is necessary, announcing what it shall be.
    In another view of the question, it may be assumed, either that an urgent distress signal will be so seldom used, that its meaning will not be remembered at the proper time by observers who witness it, or that it will gradually fall to the level of a simple means of attracting attention. The latter possibility is strengthened by the thought that what is at one time a trivial want in a ship, may be at another a matter involving her safety. Unless, therefore, every particular occasion on which a distress signal may be lawfully used is prescribed, the captain of the vessel must be left judge of the urgency of his wants, and the strong probability is that he will generally consider them so urgent as to authorise the use of whatever means may be best adapted to obtain their supply.
    It is sufficiently evident that our real aim should be, not the providing of an empirical special signal covering all wants under the general phrase, "Urgent distress," but the supply of the means by which ships of the Mercantile Marine shall be enabled to express their particular wants.
    These means are now, by international arrangement, made applicable to the ships of all nations, by the use of the ordinary coloured flags in the day-time. It may be debated whether simpler and more efficient means might not be had, for there is, after all, a good deal of trouble and inconvenience in the use of flags for the requirements of merchant ships; but, so far as it goes, there can be no doubt of the advantages conferred by the plan. A more immediate object for the Telegraph Engineer than the improvement of signalling between merchant ships in the clear daylight, should be devising means for communicating at night, and in fog. It is impossible to say for certain, without trial, whether the means used in the English and many foreign navies will be found ultimately available for the mercantile marine, but whatever arrangements become successful which are of the nature of visual or audible signals, it may be prescribed for them that they must be extremely simple; easily mastered, and easily retained in the memory; they must attract attention very easily--much more easily than anything now used in merchant ships; they must not involve preparation beforehand, nor time in their display. It is probable, also, that they must be such as to come naturally into constant use, because it is a known fate of all special arrangements to be either absent or overlooked when the occasion for then arises.
    We should, in short, make a very considerable advance in nautical telegraphy, if we could supersede the methods of attracting attention now in ordinary use afloat, by some plan which would not only attract attention, but express the particular want to which that attention is required.