Evening Republican, Volume 18, Number 250, Rensselaer, Jasper County, 22 October 1914 — LONGER EARS FOR SHIPS [ARTICLE+ILLUSTRATION]

LONGER EARS FOR SHIPS

by ROBERT H. MOULTON.

ur 8 A RESULT of the Titanic disaster, Sir XI Hiram Maxini, the inventor of the I Maxim gun, has evolved a plan for giv--17 I ing ships a “sixth sensb” that will enable ythem to avoid icebergs in a fog by the same means by* which a bat finds its way about in„ the dark. For a year or more he has been working on a device which he claims will enable a vessel to detect a floating object'several miles away, to estimate its size, shape and distance, and to recognize the character of a neighboring shore, so that a har-

bor, for instance, may be safely entered in a fog. All this is to be pone simply by receiving and recording the echoes sent back by the objects to be detected; but the sound that produces the echoes is not high enough in pitch to be audible. Its vibrations are powerful and slow and are given out by a' huge siren at the ship’s bows. The echoes are received and recorded by apparatus that serve as ears and. which are able to give us much more information than a real ear could do. This latest collision preventer is another - adaptation of a phenomenon in the natural world. Sir Hiram Maxim has taken his cue from the bat, which he was reminded is enabled to tell the distance of objects by the beat of its wings. In bats the sense organs are highly developed. When a bat flies about in" total darkness the beat of Its wings sends out a series of pulsations, or waves. These waves strike against all surrounding objects and are reflected back and received by the sensitive organs which form part of the face of

J£® ba A Th ! eXt f emely delicate nature of the ita j-rfh lß8 ’ togetber the sensitiveness of nfrvl S K? Se ™ ntalned its delicate face e ? e ® the bat to U( ige the distance of any object by the lapse of time between the sending out and the receiving of the waves. It is this exceptional mechanism, and not any faculty of seeing in the dark, which enables the bat to fly unerringly without the least light to guide it. This was proved a hundred years ago by the Abbe Spallanzani, who made experiments by blotting ou the eyes of bats with red hot irons and found that they got along Just as well without eyes as with them. Other experiments, without cruelty, may be made to show the same thing. We all know that if we capture a wild bird and liberate it in a large room with closed windows, it makes a wild and furious rush for what its senses tell it is an opening through which it can escape. Its eyeß do not reveal the presence of the glass, and the result is a broken neck. A bat liberated under similar circumstances makes the Bame dash for freedom. The flapping of its wings, however, brings its sixth sense into action and it soon perceives that it is face to face with a solid wall and stops short before it touches the glass. , Sir Hiram proposes to apply this sixth sense to sea-going vessels. His apparatus will produce atmospheric vibrations of about the same frequency as those produced by the bat, but of energy at least three hundred thousand times as great. These will not be audible, but they will travel at least twenty miles, so that they could be received and recorded by a suitable apparatus at that distance, and would be able to travel at least five miles and return back to the ship a reflected echo that would be strong enough to be detected. In describing his invention, Sir Hiram Btates that it might be considered an artificial ear. The apparatus is provided with a large diaphragm tightly drawn over a drum-shaped cylinder, and so arranged that the atmospheric pressure is always the same on both sides, quite irrespective of any air blast. It is therefore always able to vibrate freely in response to the staves of the echo, and its vibrations are made to open and dose certain electrical circuits which ring a series of bells of various sizes. If, for example, the object is very small or at a very great distance from the ship, a very small bell rings, while a large object at a distance of two miles would % ring a larger bell, and a very large object a still larger bell. The apparatus gives an audible notice if anything is ahead of the ship. Another apparatus, similar to the first, is provided, but instead of ringing a bell ft produces a diagram of the disturbances in the air—that is, when there Is no noise except that due to the action of the ship or the sea waves, a wavy line is produced on paper, but whenever the vibrations sent out by the vibrator strike an object and return, the wavy line on the paper becomes very much increased in amplitude, so as to be easily , observed, and the distance that the object is from the ship can be measured by the length of the ,paper strip between the giving off of the vibrations and the receiving of the echo. In this way the distance of the object can be determined with a considerable degree of ficcuracy, and the size of the object may be determined by the amplitude of the waves that return. The apparatus for producing the atmospherlo vibrations should be placed well forward on the snalsi deck or In any ether position where it can

be turned from port to starboard. Of course, there would be no use for the apparatus except in dark, stormy or foggy weather unless it was to be used in comnpmicating with other ships. If the sea were perfectly clear the blasts sent out would be recorded at the very instant of their production, but no echo would be produced. But if there should happen to be an object of any considerable size at a distance no greater than two or three miles the zigzag line on the paper would be changed, the amplitude of the waves would be greater and would be very noticeable. To make sure, the blasts could be repeated several times { and then if the result was always the same, it would indicate the presence of some object, and the length of paper between the primary blast and the echo would indicate the distance that the object whs from the ship. It might be so arranged that one inch of paper represented a mile. To many it will appear difficult to reveal not only the presence of objects at sea, but also their size, distance and character, by simply sending out vibrations and receiving echoes. Sir Hiram assures us, however, that such an echo properly received and recorded will not only indicate size and shape with a fair degree of accuracy, but direction and distance with great accuracy. It will distinguish, a ship from an iceberg, will show whether the is stationary or moving, and, if moving, the direction and velocity of such movement Let us embark, in imagination, on a ship equipped with Sir invention. We are well out at sea, our ship making 20 miles an hour, and we find, upon sending out several blasts, that the echo reaches us in 20 seconds. We infer that, as it took ten seconds for our vibrations to reach the object and another ten seconds for the reflected vibrations to return, the distance is slightly over two miles. One minute later we send out another blast, but the result is no stronger than before, so we change the direction of the blast and find that the greatest effect is produced when the blast is sent out dead ahead; also, that the distance between the object and our ship is being reduced at the rate of 35 m miles an hour. Inasmuch as our ship is making known object is a ship making 15 miles an hour and traveling toward us slightly to our starboard. Our next blast shows us that the ship is only a mile distant, and very much to the starboard. We follow her direction and when she is in a position to present her broadside to us, we find on sending out a blast that the echo is very strong, the bells at the receiver ring violently and the recorder makes a large and distinct marking on the paper strip. The weather has been so thick that we have not semi the ship, but we have a fair idea of her; we know her bpeed and the direction in which she is sailing. Later on, we receive a series of records from each blast, showing that there are several small objects in our vicinity, probably fishing boats. We are able to locate them and measure their distance, and if any of them are dead ahead of us, we change our direction so as to give them a wide berth. Subsequently we have a new experience. We send out a blast and receive back an .echo show-. lng that there is an exceptionally large object very nearly dead ahead of us. We know 1£ is large, because the distance Indicated is ten miles and the record quite distinct. By sending out

repeated blasts we find'that the distance between us and the object diminishes about one-third of a mile in a minute. This, of course, is due to our own speed and indicates that the object is stationary. When we are two miles apart the reflection of our blasts rings the bells and the indicator shows a different record from what we

have seen before. The markings on the paper strip are of considerable size and commence sharp and abrupt, but the ending is not sharp or distinct. There is a trailing out of spots made by the zigzag lines. The total length of the echo is thus made larger than that produced by the primary blast. This shows that there is some kind of a cloud About the object of a different density from the surrounding ait and that it is of considerable size. The logical conclusions drawn are: the object is of great size; it is stationary and it has something about it that modifies the echo. Consequently the record on the paper strip resembles that obtained from both a large, solid object and a cloud. Therefore, it must be a large iceberg surrounded by cold air. ' We change our direction so as to paBS it on our port side at a distance of half a mile. Fortunately we have barely passed when the fog lifts

and discloses an enormous iceberg surrounded by smaller pieces that have broken off. Returning to realities, Sir Hiram states that while the apparatus will work exactly as described with the devices already designed, he is not going to rest- at this point. He says that he will shortly produce a recording instrument with a selective power that will not receive any vibrations except those due to the echo of the blast sent out. This will eliminate all noises due to the ship and the sea, and produce a very clean record.