Popular Science Monthly/Volume 24/March 1884/Science and Safety at Sea
|SCIENCE AND SAFETY AT SEA.|
IN the autumn of 1879 the steamship Arizona, five thousand tons, at that time the swiftest ocean-going steamship in existence, was urging her way, at the rate of some fifteen knots an hour, on the homeward course from New York, whence she had sailed but a day or two before. It was night, and there was a light haze, but of danger from collision with a passing ship there was little or none. The captain and crew knew of no special reason for watchfulness, and the passengers were altogether free from anxiety. Indeed, it so chanced that at a time when, in reality, the most imminent danger threatened every soul on board, many of the saloon-passengers were engaged in purchasing at auction the numbers for the next day's run—runs below three hundred and fifty knots being sold at a very low rate indeed. Suddenly a crash was heard, the ship's swift progress was stopped, and a few minutes later every one knew that the Arizona had run dead upon an enormous iceberg, the spires and pinnacles of which could be seen hanging almost over the ship, and gleaming threateningly in the rays of her mast-head light. But the risk that threatened her living freight was not that of being crushed by falling ice. The bows of the Arizona were seen to be slowly sinking, and presently there was a well-marked lurch to starboard. The fore compartment and a smaller side compartment were filling. It was an anxious time for all on board. Many an eye was turned toward the boats, and the more experienced thought of the weary miles which separated them from the nearest land, and of the poor chance that a passing steamer might pick up the Arizona's boats at sea. Fortunately, the builders of the Arizona had done their work faithfully and well. Like another ship of the same line which had been exposed to the same risk, save that her speed was less, and therefore the danger of the shock diminished, the Arizona, though crippled, was not sunk. She bore up for St. John's, and her passengers were taken on later by another steamer.
The danger which nearly caused the loss of the Arizona—collision with an iceberg—is one to which steamships, and especially swift steamships, are exposed in exceptional degree. Like this danger, also, it is one which renders the duty of careful watching, especially in the night and in times of haze or fog, a most anxious and important care. But, unlike the risk from collision with another ship, the risk from collision with icebergs can not be diminished by any system of side-lights or head-lights or stern-lights, except in just such degree (unfortunately slight) as a powerful light at the foremast-head, aided by strong side-lights or bow-lights, may serve to render the gleam of the treacherous ice discernible somewhat farther ahead. But to a steam-ship running at the rate of fourteen or fifteen knots an hour, even in the clearest weather, at night, the distance athwart which a low-lying iceberg can be seen, even by the best eyes, is but short. She runs over it before there is time for the watch to make their warning heard, and for the engineers to stop and reverse their engines.
But science, besides extending our senses, provides us with senses other than those we possess naturally. The photographic eyes of science see in the thousandth part of a second what our eyes, because in so short a time they can receive no distinct impression at all, are unable to see. They may, on the other hand, rest on some faintly luminous object for hours, seeing more and more each moment, where ours would see no more—perhaps even less—after the first minute than they had seen in the first second. The spectroscopic eyes of science can analyze for us the substance of self-luminous vapors or of vapors absorbing light, or of liquids, etc., where the natural eyes have no such power of analysis. The sense of feeling, or rather the sense for heat, which Reid originally and properly distinguished as a sixth sense (not to be confounded, as our modern classification of the senses incorrectly confounds it, with the sense of touch), is one which is very limited in its natural range. But science can give us eyes for heat as keen and as widely ranging as the eyes which she gives us for light. It was no idle dream of Edison's, but a thought which one day will be fraught with useful results, that science may hereafter recognize a star by its heat, which the most powerful telescope yet made fails to show by its light. Since that was said, the younger Draper (whose loss followed so quickly and so sadly for science on that of his lamented father) has produced photographic plates showing stars which can not be seen through the telescope by which those photographs were taken. As yet the delicate heat-measurers devised by science have not been applied to astronomical research with any important results. But Edison's and Langley's heat-measurers have been used even in this way, and the very failure which attended the employment of Edison's heat-measurer (the tasimeter, or, literally, the strain-measurer, described shortly before in the "Times") during the eclipse of 1878 shows how delicate is the heat-estimating sense of science. When the light of the corona—which has no heat that the thermometer, or even that far more delicate heat-measurer, the thermopile, will recognize—fell on the face of the tasimeter, the index which Edison supposed likely, to move just perceptibly actually flew beyond the index-plate. Thus, though the heat of the corona could not be measured, the extreme delicacy of the tasimeter was demonstrated unmistakably. Langley's heat-measurer is scarcely less sensitive, and probably more manageable. But in point of fact each instrument is more sensitive than the heat-sense of science is required to be, to do the work I have now to indicate; and an instrument can readily be constructed which shall be, in the right degree, less sensitive than they are, though it might be difficult at present to invent any that should be more .
The sense of sight is not the only sense affected as an iceberg is approached. There is a sensible lowering of temperature. But to the natural heat-sense this cooling is not so obvious or so readily and quickly appreciated that it could be trusted instead of the outlook of the watch. The heat-sense of science, however, is so much keener that it could indicate the presence of an iceberg at a distance far beyond that over which the keenest eye could detect an iceberg at night; perhaps even an isolated iceberg could be detected when far beyond the range of ordinary eye-sight in the day-time. Not only so, but an instrument like the thermopile, or the more delicate heat-measurers of Edison and Langley, can readily be made to give automatic notice of its sensations (so to speak). As those who have heard Professor Tyndall's lectures any time during the last twenty years know, the index of a scientific heat-measurer moves freely in response either to gain or loss of heat, or, as we should ordinarily say, in response either to heat or cold. An index which thus moves can be made, as by closing or breaking electrical contact, or in other ways, to give very effective indication of the neighborhood of danger. It would be easy to devise half a dozen ways in which a heat-indicator (which is of necessity a cold-indicator), suitably placed in the bows of a ship, could note, as it were, the presence of an iceberg fully a quarter of a mile away, and speak of its sensations much more loudly and effectively than the watch can proclaim the sight of an iceberg when much nearer at hand. The movement of the index could set a fog-horn lustily announcing the approach of danger; could illuminate the ship, if need be, by setting at work the forces necessary for instantaneous electric lighting; could signal the engineers to stop and reverse the engines, or even stop and reverse the engines automatically. "Whether so much would be necessary—whether those among lost Atlantic steamships which have been destroyed, as many have been, by striking upon icebergs, could only have been saved by such rapid automatic measures as these—may or may not be the case; but that the use of the infinitely keen perception which the sense-organs of science possess for heat and cold would be a feasible way of obtaining much earlier and much more effective notice of danger from icebergs than the best watch can give, no one who knows the powers of science in this direction can doubt.—London Times.