each lighthouse, and it would be necessary for that letter to be added whenever the light was described or referred to. This also would be source of inconvenience to seamen, and would not be welcomed by them.

Moreover, as there are only 26 distinctions available by the Morse alphabet, and as, according to Sir William Thomson, the number of lights on our coasts exceeds 600, it would be necessary to repeat the alphabet about twenty-four times in order to give every light a letter. It is difficult to see how confusion would be avoided in the case of the lights on the East coast of Ireland and those on the West coasts of England and Scotland; and there is no doubt that the lighting arrangements of the North coasts of France, Belgium, and Holland would be seriously interfered with if the proposed system were to come into operation on the British coasts.

Again, the mariner would also have to remember that sometimes the signals would be conveyed by means of long and short flashes of light, and sometimes by means of long and short intervals of darkness. In the one case, continuous darkness would be broken by flashes of light; in the other, continuous light would be broken by flashes (so to speak) of darkness. To mistake the one for the other of these two classes might be disastrous in the extreme, and to our thinking it seems that as the sailor's mind would be bent almost entirely upon making out the dots and dashes, he would be apt to confuse the two classes, and might substitute one for the other.

But assuming, for the sake of argument, that these preliminary hindrances to the application of Sir William Thomson's proposal could be all satisfactorily overcome, the question then arises: What practical advantages would the mariner derive from the special forms of distinction proposed? In the place of the present highly varied system, he would find all the lights perpetually bobbing and jumping, and each by its continual Jack-in-the-box movement, firing off the necessary groups of dots and dashes to signalise the letter which may have been appropriated to it. Sir William makes no provision for any other kinds of distinctions to be used, and would abolish the use of colour except for sectors for local purposes, so the mariner would see nothing but white

C

lights continually on the move. It is true that they will differ from the masthead lights of steamers under way, which appears to be one of the chief objects aimed at, but the anchor light of a vessel rolling ever so little to the action of the waves is always liable to be characterised by what may be termed occultations produced by the interference of masts, rigging, sails, smoke, steam, or passing vessels, and although the occultations so produced might not be regular, yet they might be sufficiently marked to cause considerable doubt in the mind of the seaman as to what light it could be, and to involve a great loss of time in his endeavours to find out.

But another great advantage which Sir William Thomson claims for his proposal is, that it will greatly facilitate the picking up of a light in comparison with the means offered by the present system of distinctions.

We have already shown that the adoption of the proposed system would involve the shortening of the duration of the flashes themselves, even to such short periods as one second and half-a-second, and it is probably believed, on the other hand, that the increased frequency of their recurrence would obviate any inconvenience which might be caused by reducing the duration of the flash to such exceedingly short periods. But it must not be forgotten, that the construction of the optical apparatus of the revolving lights now in operation is such that it will not admit of the flash being reduced without a considerable loss in the intensity of the light. A flash of some seconds' duration sent through a panel of, say, a six-sided apparatus, consists of a great amount of light gathered up into a powerful beam; but in order to produce these rapidly recurring flashes, the body of light falling upon the panel must be cut up into a great number of very small sections, and the light sent through each section would be, in comparison with the large beam transmitted through the entire panel of 60°, weakened in proportion to the reduction of the angle into which the light is gathered. But, besides this, a mechanical obstruction exists which would make it extremely difficult to apply the system of short and quick flashes to existing revolving lights. It would either be necessary to completely alter the optical arrangements (which would involve an enormous

expenditure), or the apparatus would have to be rotated so rapidly that one man would be chiefly occupied in winding up the clockwork, to say nothing of the inconvenience, risk, and wear and tear with which so rapid a velocity of the glass apparatus would be attended.

But, under any circumstances, the intensity and penetrating power of the light would be lessened by the adoption of quickly recurring short flashes. The mariner thereby would lose the power, and possibly the visibility of the light, for the sake of gaining the dot-flash system of distinctions. At times when the light would be most required, its intensity would be enfeebled, and through haze, rain, or snow, he might with difficulty make out faint blinkings, which it would require the most careful observation and thought to interpret. We ask our readers, the majority of whom know practically what is wanted, will they sacrifice intensity of light for the sake of a new code of distinctions? and would the mariner be assisted in picking up any given light by its change to rapidly recurring but enfeebled flashes?

But we have another point to make against the dot-and-dash system. What the mariner really wants is a light which immediately it is sighted proclaims to him its own individuality. This would not be the case with the dot-and-dash system of signalling, even though the Morse Code were as familiar to him as the letters of the alphabet. Sir William Thomson, on board H.M.S. Northampton, or his own comfortable yacht, would no doubt be in a position to devote all his attention to the minute observance of lights. In his letter to the Times he admits that when criticising the performances of some of the channel lights, his mind was free from navigational anxiety, and as a scientific observer he has devoted himself entirely to the question.

To Sir William Thomson the Morse Alphabet is "as easy as A B C," he can see no difficulty in reading the signals-his mind is full of it-and what is so simple and intelligible to him must, he appears to think, be equally comprehensible to everyone else. But we must remind Sir William Thomson that merchant sailors are not all scientific observers, nor able to sympathise with ingenious scientific theories. However competent the commanders and officers

of our great steamships may be to appreciate a complex system of signalling, it must be borne in mind that the lighthouses of our coasts are also intended for the use of thousands of men to whom the details of short and long flashes, the Morse Code, &c., would be merely so many additional perplexing elements in the performance of the business of their lives.

Imagine the master of a small trader, on a rough night, with his mind full of the hundred and one matters connected with the navigation of his vessel, yet anxious to assure himself of his position; would he wish to add to his already burdened mind the task of deciphering the meaning of what would appear to him, at first sight, to be a very rapidly blinking light. To do so he must give up for the time all thought about his ship; he must concentrate all his faculties on the light; he must find out first the number of flashes or occultations in a given period, and must then decide which of them are long and which are short; having after repeated observations satisfied himself on this point, he must then remember or find out what letter is symbolised, and having accomplished that must then recollect or search out to what light the letter in question is appropriated. And all this it would be necessary for him to do at a time when the light was just showing above the horizon, and he was in an anxious state of mind, wishing to verify his position. We venture to think that practical seamen will regard this multiplication of the efforts necessary to determine the name of a lighthouse as a fatal objection to the introduction of such a system of lighthouse distinctions. If every nautical man had the Morse Alphabet at his fingers ends; if the signals could be conveyed with the greatest certainty and intelligibility; if the short flashes of light retained the intensity which the longer flashes possess; if the mind of the sailor were in a state of absolute certainty as regards the "flashing" system and the "occulting" system; and lastly, if the existing system of distinctions were so lamentably deficient as to provoke the outcries of those who require to make use of the lights, and to lead to disaster, then we would be disposed to look with more favour on the proposition of Sir William Thomson, and the necessities of navigation would, no doubt, call for its adoption if nothing better opposed it.

But our readers will probably ask: What does the present system consist of? To this we answer that it appears to be a combination of many systems by which an effective variety of distinctions is obtained. But one great merit pervades the present heterogeneous collection of distinguishing characteristics. Every light says at once what it is; there is no code of symbols or letters to be interpreted-the Wolf Rock Light is revolving, showing a red and a white flash alternately every half minute; the light on the Mull of Galloway in Scotland is intermittent or occulting, showing a fixed light for half-a-minute then eclipsed for fifteen seconds; the Calf Rock Light on S.W. Coast of Ireland is flashing, showing a flash every quarter of a minute; then there are fixed lights, red and white; revolving, white or red or green; double lights shown from one tower; or from two lighthouses a short distance from each other; electric lights which are very distinctive; sundry combinations of fixed and flashing; and a system of recent introduction known as group flashing, whereby two or more flashes in quick succession are repeated at certain periods. The above characteristics and their combinations, varied by time periods ranging from ten seconds to two minutes, afford a much larger number of distinctions than could be obtained by the dot-and-dash system alone, with the advantage that the seaman knows at once what he is looking at.

We do not pretend to affirm that the lighting arrangements on our coasts are perfect; there are doubtless many improvements which may be made, particularly in the general direction indicated by Sir William Thomson in regard to shortening the period of darkness in revolving lights. But, in the absence of complaints from seafaring men, it may fairly be assumed that the arrangements are generally effective and do not call for any revolutionary change. The steady progress made during the past twenty years in all that relates to lighthouse illumination, the increased efficiency and number of lights, the development of sound-signalling for foggy weather, the improvements in and increase in the number of buoys, afford sufficient reasons for the nautical community to be satisfied with what is being done for them, and explain the apathy with which they have regarded the efforts of even a distinguished man of science like Sir William Thomson to bring about a scheme which does not