A NEW SYSTEM FOR
PREVENTING COLLISIONS AT SEA

HEAD OF BLAINVILLE'S BAT.

Some have suggested that the alleged sixth sense of the
Bat is nothing more nor less than the sense of feeling. To
a certain extent this is true, but the same thing can be said
of every sense that we possess.

The Bat has an organ that we do not have which
enables it to get a very fair idea of its surroundings without
the use of either ears or eyes. This organ is peculiar to
itself, and does not resemble any other known organ of
sense.

A bird certainly has the sense of feeling highly developed,
but it is quite helpless if deprived of its eyes, whereas ex-
periments show that all Bats which possess the organ of
the sixth sense do just as well without eyes as with them.
This sense is certainly quite distinct from that of seeing or
hearing ; therefore are we not justified in designating it as
"The Sixth Sense"?

Measures have already been taken for securing Patents
in the leading countries of the world on the apparatus,
devices, and mode of operation shown in this pamphlet.

HIRAM S. MAXIM.

LONDON, June, 1912.

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A record made tn a v*ry brighf-and hot day, -The changing current's A /ow and s/optng Cocrs-f erf a c/t stance of Two Afi/es with htgh and
of hot and co/d air form Acoustic C/ouds fhafrcS/ecT -f-h& v/braftons Afovnfatnot/s ground tn the rear.

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A NEW SYSTEM

FOR PREVENTING
COLLISIONS AT SEA

BY

SIR HIRAM S. MAXIM

PRINTED FOR THE AUTHOR BY

GASSELL AND COMPANY, LIMITED

London, New York, Toronto and Melbourne
1912

ALL RIGHTS RESERVED

o

CONTENTS

PAGE

INTRODUCTION . . xi

A NEW SYSTEM FOR PREVENTING COLLISIONS AT

SEA i

A SIXTH SENSE . . ... 3

THE APPLICATION OF THE SIXTH SENSE TO SHIPS . 22

SOME REMARKS ON THE OPERATION AND USE OF
THE APPARATUS . .26

ICEBERGS 43

LIST OF ILLUSTRATIONS

Specimens of Records that might be received from Echoes

Frontispiece

PAGE

Head of the Long-eared Bat 7

Head of the African Magaderm ..... 7

Head of the Lyre Bat (Hilarious Bat) .... - 8

Head of the Mourning Horseshoe Bat 8

Head of Townsend's Bat 9

Head of Gestoni's Bat ........ 9

Head of the Speckled Vampire Bat . . . . .10

Head of the Lesser Horseshoe Bat 10

The Barbastelle 10

Mouth of the Spectacled Stenoderm . . . . n

The Trident Bat n

The Diadem Bat . .' 12

Head of the Greater Horseshoe Bat 12

Head of the Collared Bat 13

Head of Blainville's Bat 13

Head of the True Vampire Bat 14

Head of the Grey Fruit Bat 14

Head of the Kalong . . .15

List of Illustrations

PAGE

Welwitsch's Bat . . . .16

Plate 1. — Vertical Central Section of the Apparatus for

Producing the Vibrations 36

Plate 2. — Side Elevation of the Siren or Vibrator . . .37

Plate 3. — Receiver that Makes and Breaks Electrical Circuits

for Ringing Bells 39

Plate 4. — Receiver for Recording the Vibrations . . 40

Plate 5. — System of Mounting the Receivers . . . .41
Iceberg in the South Pacific ....... 44

INTRODUCTION

THE sinking of the Titanic, although the greatest catastrophe
of the kind, is by no means an isolated case. Many other
large ships have been destroyed or lost at sea, some of them
having disappeared without leaving the least trace of what
had happened to them, but the number of ships, though very
considerable, which have been lost in the open sea by col-
lisions with other ships or with icebergs, is extremely small
in comparison with those which have been lost by running
on to rocks or running ashore in a fog. I have seen a chart
called the " Caviare " map, in which a little black dot repre-
sents the locality where a ship has been lost, and these little
black dots are so numerous about the coasts of England,
Ireland, Norway, Sweden and Denmark as to give the map
the appearance of a lot of caviare, consequently the name.

Professor John Tyndall, " the poet of science," was in-
structed by the British Government to conduct certain experi-
ments with the view of obtaining the best means of preventing
ships from running ashore in a fog. After a great number
of lights, electrical and otherwise, had been tried with very
indifferent success, experiments were made with sound-pro-
ducing instruments, such as very large steam whistles, enormous
trumpets worked with compressed air, and a siren specially
constructed for fog-signalling and much used in the United
States. Guns were also used of various sizes and with varying

xi

Introduction

charges. In some cases, the sound of the guns travelled
farther than that of any other instrument ; in some cases
the trumpet and siren were about equal, but in most cases
the siren did the best. But there is something besides
carrying power in the siren which makes it eminently well
qualified for sending out powerful vibrations and receiving
back the echo.

Professor Tyndall tells us not only that the reflection of
sound from a solid body like a ship is very great, but
also that he got astonishing results from acoustic and in-
visible clouds :

u On the i yth of October, at about 5 p.m., the air being perfectly
free from cloud, we rowed towards the Foreland, landed, and passed
over the seaweed to the base of the cliff. As I reached the base
the position of the Galatea was such that an echo of astonishing
intensity was sent back from her side ; it came as if from an
independent source of sound established on board of the steamer.
This ceased suddenly, leaving the aerial echoes to die away
gradually in silence."

On some occasions the learned professor was greatly
puzzled. Sometimes at a distance of three miles he was quite
unable to hear the report of the guns or the sound of the
whistles or sirens, while on other days these could be
heard at a distance of nine or ten miles. On one occasion
they drew up as near as two and a half miles to the shore
and still the sounds were inaudible. Suddenly a cloud ob-
scured the sun, a dark shadow overspread the sea ; then
every instrument was heard, and, while the cloud was still
obscuring the sun, they withdrew to a distance of six miles
and practically all the instruments were heard.

On another day while experimenting, the air was optic-

xii

Introduction

ally clear, not the least sign of a cloud in sight and the sun
was shining down with merciless intensity, making everything
hot that it struck. There was very little wind. Under
these conditions all the instruments were inaudible at a
distance of two miles.

It then occurred to the Professor that there was an
acoustic cloud between the instruments and the ship, and he
reasoned it out in this way : when the sun shines on an
ordinary cloud, the cloud refuses passage to the light ; the
light is broken up and numerous reflections take place ; the
light is not all lost — some of it is reflected. The side of a
cloud that the sun shines on is very bright ; why, then,
should there not be a similar result from an invisible acoustic
cloud ? The immense energy of the sound sent out must
go somewhere ; if the cloud refuses its passage, would it not
be sent off in the other direction ? Would it not be reflected
back as is the case with light on a common cloud ? As he
could get no response from the sound sent out, he thought
he would see what he could obtain from the other side of
the cloud. I quote the following: —

" It is incredible that so great a body of sound could utterly
disappear in so short a distance without rendering some account
of itself. Supposing, then, instead of placing ourselves behind the
acoustic cloud we were to place ourselves in front of it, might
we not, in accordance with the law of conservation, expect to re-
ceive by reflection the sound which had failed to reach us by
transmission? The case then would be strictly analogous to the
reflection of light from an ordinary cloud to an observer between it
and the sun.

" My first care in the early part of the day in question was
to assure myself that our inability to hear the sound did not arise
from any derangement of the instruments on shore. Accompanied
by Mr. Price Edwards at I p.m., I was rowed to the shore, and

xiii

Introduction

landed at the base of the South Foreland cliff. The body of air
which had already shown such extraordinary power to intercept
the sound, and which manifested this power still more impressibly
later in the day, was now in front of us. On it the sonorous waves
impinged, and from it they were sent back with astonishing in-
tensity. The instruments, hidden from view, were on the summit
of the cliff 235 feet above us, the sea was smooth and clear of
ships, the atmosphere was without a cloud, and there was no object
in sight which could possibly produce the observed effect. From
the perfectly transparent air the echoes came, at first with a strength
apparently little less than that of the direct sound, and then dying
away."

Professor Tyndall shows the necessity of using sound-
producing instruments in foggy weather instead of attempting
to penetrate the fog with a light :—

u The cloud produced by the puff of a locomotive can quench
the rays of the noonday sun ; it is not therefore surprising that
in dense fogs our most powerful coast lights, including even the
electric light, should become useless to the mariner.

" Disastrous shipwrecks are the consequence. During the ten
years ending in 1874, no less than 273 vessels were reported as
totally lost on our own coast in fog or thick weather. The loss, I
believe, is far greater on the American seaboard."

It is a curious and interesting fact that anything in the
nature of a light does best in perfectly clear weather, while
anything in the nature of a sound does best in thick or foggy
weather. Acoustic clouds that bar the passage of sound never
exist in foggy weather ; these clouds are produced by numerous
conflicting currents of air at different densities caused by the
interchange of the hot air from below with the cold air from
above, and this action never takes place in thick weather ;
therefore, acoustic clouds cannot interfere with the working
of my apparatus.

xiv

Introduction

Although I do not propose to send out vibrations that
can be considered as sound from a musical standpoint, being
too low to appeal to the human ear, still, as these atmospheric
waves or vibrations only differ from audible sound vibrations
in their length, or, in other words, there are less of them
in a given time, and as they obey all the laws that govern
sound, I propose to treat them as sound and to designate
them as sound, although they are not audible to the human
ear.

The siren furnished to Professor Tyndall by the United
States Government had a rotating disc 5 inches in diameter.
The trumpet was sixteen feet long, and the mouth measured
26 inches in diameter. It used steam at 70 Ibs. pressure to
the square inch, and gave off an audible note. The prob-
abilities are that when the steam valve was wide open the
power represented would not be more than 50 h.p.

On our large steamships, we very often have a boiler
pressure of 280 Ibs. to the square inch. Suppose, now, that
we use a rotating disc 10 inches in diameter and a trumpet
correspondingly large, we can convert 500 h.p. into sound,
sending out vibrations of enormous energy and amplitude,
which ought to travel over a distance very much greater than
would be possible with any of the instruments employed by
Professor Tyndall. As the steam valve of a siren is only
open for about a second at a time, it is very evident that the
total amount of steam consumed would not be very great,
although -the energy when it was actually escaping might be
500 h.p.

xv

A NEW SYSTEM FOR PREVENTING
COLLISIONS AT SEA

THE wreck of the Titanic was a severe and painful shock
to us all ; many of us lost friends and acquaintances by
this dreadful catastrophe. I asked myself: "Has Science
reached the end of its tether ? Is there no possible means
of avoiding such a deplorable loss of life and property ?
Thousands of ships have been lost by running ashore in a
fog, hundreds by collisions with other ships or with icebergs,
nearly all resulting in great loss of life and property."

At the end of four hours it occurred to me that ships
could be provided with what might be appropriately called
a sixth sense, that would detect large objects in their im-
mediate vicinity without the aid of a searchlight.

Much has been said, first and last, by the unscientific ot
the advantages of a searchlight. Collisions as a rule take place
in a fog, and a searchlight is worse than useless even in a light
haze, because it illuminates the haze, making all objects beyond
absolutely invisible.

Some have even suggested that a steam whistle or siren
might be employed that would periodically give off an
extremely powerful sound, that is, a veritable blast, an ear-
piercing shriek, and then one is supposed to listen for an echo,
it being assumed that if any object should be near, a small
portion of the sound would be reflected back to the ship, but
B i

A New System for Preventing Collisions at Sea

this plan when tried proved an absolute failure. The very
powerful blast given off by the instrument is extremely painful
to the ears and renders them incapable of hearing the very
feeble echo which is supposed to occur only a few seconds
later. Moreover, sirens or steam whistles of great power
are extremely objectionable on board passenger ships ; they
annoy the passengers and render sleep impossible. It is, there-
fore, only too evident that nothing in the way of a light or
noise producing apparatus could be of any use whatsoever.

A SIXTH SENSE

ALL warm-blooded animals, including Man, are provided
with five senses, i.e. seeing, hearing, tasting, feeling, smelling.
I now propose to show that there are certain kinds of animals
which have a sixth sense, and that with this sixth sense they
are perfectly able to detect objects in their vicinity, to
determine their character, and to move about with great
rapidity and perfect ease when deprived of both sight and
hearing, thus proving most conclusively that they possess a
sixth sense. I also propose to show that by mechanical
means, we can provide a ship with a similar sense, not, of
course with the wonderful sensitiveness found in nature, but
sufficiently sensitive to detect any large object in the vicinity
of the ship, to indicate with a great degree of nicety its dis-
tance from the ship, and also to give a fair idea of its
size and character.

Before explaining this apparatus, I propose to prove that
a certain animal does have a sixth sense.

We are able to see perfectly in twilight which appears to
be complete darkness to a common fowl. A horse can see
better in the dark than we are able to do, and the cat and
owl with their very large eyes are able to see sufficiently
well to get about when there is very little light. However,
no eye, no matter how large or perfect it may be, is of the
least use in total darkness.

About a hundred years ago, the Abbe Spallanzani dis-

3

A New System for Preventing Collisions at Sea

covered that certain kinds of bats had a veritable sixth sense ;
he noticed that the particular kind that possessed this re-
markable sense was only provided with extremely small eyes
that could be of little or no use to them in the dark — still
they found their way about quite as well as cats and owls
which have very large eyes. He then made experiments by
blotting out the eyes of bats with red-hot irons and found
that they got along just as well without eyes as with them.
I quote the following from Cassell's Natural History :—

" He blinded these animals, sometimes by burning the eyes
with a red-hot wire sometimes by removing the organs altogether,
and even filling up the orbits with wax, and then allowed them
to fly. In spite of the mutilation, the unfortunate little creatures
continued quite lively, and flew about as well as those which still
retained their eyes ; they did not strike against the walls of the
room, or the objects in it, avoided a stick held up before them, and
showed a greater desire to keep out of the way of a cat or the
hand of a man than to escape contact with inanimate objects. One
of these blinded bats was set free in a long underground passage,
which turned at right angles about its middle. It flew through
the two branches of this passage, and turned without approaching
the side walls. During its flight it detected a small cavity in the
roof at a distance of eighteen inches, and immediately changed
its course in order to conceal itself in this retreat. In a garden
a sort of cage was prepared, with nets, and from its top sixteen
strings were allowed to hang down. Two bats were introduced into
this enclosure, one blinded, the other with its eyes perfect. Both
flew about freely, never touching the strings with more than the
tips of the wings. Finally, the blind bat discovered that the meshes
of the enclosing net were large enough for it to get through, and
made its escape ; and after flying about for a time, made its way
rapidly and directly to the only roof in the neighbourhood, in which
it disappeared. In a room containing numerous branches of trees, or
in which silk threads, stretched by small weights, were suspended
from the ceiling, the bats, though blinded, avoided all these
obstacles ; and when, after tiring themselves with their aerial evolu-

A Sixth Sense

tions, they settled on some object for the sake of rest, they would
immediately rise again on an attempt being made to seize them with
the hand.

" From these experiments it was perfectly clear that in threading
the galleries of caverns and other narrow and pitch-dark places
to which bats commonly resort for their diurnal repose, these
animals were guided by some other sense than that of sight, and
the worthy abbe set himself to ascertain what this sense might
be. He commenced operations by covering the body of one of
his blind bats with varnish, and found that this had no effect in
rendering its movements uncertain. He then stopped up the ears
with wax, and finally with melted sealing-wax, and still the bats
obstinately persisted in avoiding obstacles placed in their way.
Consequently they did not hear their way in the dark. There
remained the senses of smell and taste. To test the former the
nostrils were stuffed up, but the only effect of this operation was to
bring the creature speedily to the ground, owing to difficulty of
breathing. Little fragments of sponge impregnated with musk,
camphor, or storax were fastened in front of the nostrils, and then
the bats flew about as freely as ever, and showed the same power of
avoiding contact with objects in their path. The removal of the
tongue, as might be expected, produced no result."

During the last century several others have experimented
with a view of ascertaining the manner in which bats are
able to detect objects in their vicinity without the use of eyes.
It was believed by many that they had an unknown organ
which enabled them to find their way about in the darkest
places without the use of either eyes or ears, and it was
believed that this unknown organ was situated in the head.

a Cuvier, however, who was the first really to appreciate the
results of these experiments, arrived at the conclusion, now
generally accepted, that the wonderful power possessed by bats
of directing their flight in places so dark as to render the
sharpest eyes useless was due to an exceptional development of
the sense of touch, residing especially in the great delicate mem-
branous expanse of the wings. These organs are really of the

i 5

A New System for Preventing Collisions at Sea

most delicate structure, and traversed by nerves, the fine ramifi-
cations of which terminate in little loops, like those found in
those parts of the skin in man in which the sense of touch is
manifested with the greatest perfection ; and their surface is
covered with rows of small thickened points, or papillae, which
may very probably have something to do with the perception of
exceedingly delicate tactile impressions."

All of these experimenters are fully agreed that the bat
does possess what might very properly be called a sixth sense,
and that it is able to pursue and capture small insects in the
dark under conditions in which eyes would be of little or no
use. It is a very curious fact that, notwithstanding that the
organ of the sixth sense is the most conspicuous organ pos-
sessed by the bat, none of our scientific men have discovered
it. It was evidently too apparent to be observed, and reminds
one of Christian in " Pilgrim's Progress " who was digging
in the muck for a crown when the crown in question was
directly over his head and very conspicuous. In many cases,
the organ that gives the bat the sixth sense is spread all
over its face. In the vampire bat the organ is on the tip of
the nose ; it stands up in the air, and is called the " shield,"
but in most of the small bats that catch insects on the wing,
we find two little leaves, not unlike the wings of the insect
that it pursues, standing up just in front of the ears. Others
have the sensitive spots located on other parts of the face
as will be seen by the following illustrations : —

A Sixth Sense

HEAD OF THE LONG-EARED BAT.

This bat has two wing-like leaves of great sensitiveness in front of the
ears. These are very much like the wings of the insect which it pursues. The
ears themselves are only able to hear rather high notes, but these two little
leaves vibrate in unison with very low notes, much lower than the human ear
is able to take in. It is therefore possible for this bat to pursue and capture
insects in the dark without seeing them. The little leaves really endow the animal
with a sixth sense.

HEAD OF THE AFRICAN MAGADERM.

This bat has very large ears, and is also provided with a sensitive organ
attached to the nose. It is a very fierce little beast — in fact, a species of a
vampire, and feeds not only on insects, but it kills and devours other bats.

A New System for Preventing Collisions at Sea

HEAD OF THE LYRE BAT (Hilarious Bat).

T^his bat has the sensitive membranes in the ears and also on the nose,
has fairly large eyes, and does not live altogether on insects.

It

HEAD OF THE MOURNING HORSESHOE BAT.

This bat has a very complicated sensitive organ which occupies nearly the
whole of the face. That it has very little use for its eyes is witnessed by the fact
that they are extremely small.

A Sixth Sense

HEAD OF TOWNSEND'S BAT.

V*

In this case the sensitive organ is in front of the ears and also in two egg-
shaped projections on the nose. The eyes are very small.

HEAD OF CESTONI'S BAT.

This bat has the sensitive organ in the ears and also on the upper lip. It is
the kind that one finds in the dark passages of the pyramids of Egypt ; it will be
noted that its eyes are so extremely small that they do not appear in the engraving.

A New System for Preventing Collisions at Sea

HEAD OF THE SPECKLED VAMPIRE BAT.

In this bat, the principal organ projects from the nose. It will, however, be
noted that it has the rudiments of the wing-like leaf in its ear, which shows that
its early ancestors^belonged to the kind of bats that possess this leaf. This bat
does not depend so much upon its sixth sense as many other kinds of bats, but it
is provided with a fairly large pair of eyes.

wv

HEAD OF THE LESSER HORSESHOE BAT.

It will be observed that this bat has extremely small eyes, and that the sensitive
membrane is attached to the nose and therefore cannot be considered a part
of the ear.

THE BARBASTELLE.

This bat is interesting from the fact that the organ of the sixth sense is located
inside of the ears, but there is also a sensitive spot at the tip of the nose.

10

A Sixth Sense

MOUTH

THE SPECTACLED STENODERM.

In this bat we find the sensitive organ not only in the ears and on the nose, but
the lips themselves are sensitive. Tills ^vA.uiiar arrangement enables it to seize its
food in the dark and to know exactly what it is without seeing it.

THE TRIDENT BAT.

This species has a very complicated organ which covers nearly the whole ot its
face, and is extremely sensitive. In this species it certainly cannot be claimed that
the sensitive organ of the sixth sense is a part of the ear.

II

A New System for Preventing Collisions at Sea

THE DIADEM BAT.

This'is a good example of the Leaf-nose Bat. Not only does it have the leaf
attached to its nose, but it has a little sac which secretes a wax-like substance
similar* to ear-wax. Its eyes are extremely small, nevertheless it is able to get about
in the dark quite as well as a bird would do in daylight.

HEAD OF THE GREATER HORSESHOE BAT.

I It will be observed that the sensitive membrane is attached to the nose, and
that the ears are not provided with the wing-like leaves.

12

HEAD OF THE COLLARED BAT.

This bat is interesting in so far as it occupies a place intermediate between the
bats that have six senses and those which have only five. The sensitive membrane
is very small and projects from the neck ; the face is provided with wart-like
formations each of which is covered with sensitive hairs. The sixth sense is of
very little use to this animal, but it is provided with fairly large eyes.

HEAD OF BLAINVILLE'S BAT.

In this bat, we have the highest development of the organ of the sixth sense to
be found anywhere in animated nature. The whole face, including the ears, is
covered with this organ ; the nose, ears and chin, are all occupied and covered
with sensitive hairs. The eyes are small and of very little use.

13

A New System for Preventing Collisions at Sea

HEAD OF THE TRUE VAMPIRE BAT.

This bat does not pursue insects in the air and does not fly about in total dark-
ness ; the sensitive organs, both on the nose and in the ear, are in a rudimentary
form and probably are of very little use, but the eyes are large, which show that
it depends upon the sense of sight instead of the sixth sense.

HEAD

THE GREY FRUIT BAT.

This bat does not inhabit caves or dark places, does not fly about on dark
nights, and lives exclusively on fruit. It depends altogether upon its large
eyes and moderate-sized ears, the organ of the sixth sense being completely absent.
All bats with a highly developed sixth sense are provided with extremely small
eyes, and no bat with large eyes has a highly developed sixth sense.

A Sixth Sense

HEAD OF THE KALONG.

This is a very large bat ; the body is about fourteen inches long and the wings
have a spread of four feet or more. It does not inhabit caves, but makes its home
among the thick foliage of trees. It feeds exclusively on fruit, has very large
eyes, and not the least trace of the organs of the sixth sense. It should be noted
that all bats endowed with the sixth sense are very small, and consequently move
their wings very rapidly, while the large bats with slowly moving wings never
have the sixth sense, and always have large eyes.

A New System for Preventing Collisions at Sea

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A Sixth Sense

Let us see now what takes place, and what it is that
enables the bat to fly about through all manner of obstruc-
tions without touching anything, after the manner of a swallow.
What enables it to pursue a fly or a beetle in a degree of
darkness which renders eyes useless ?

In the bats that feed on swiftly flying insects, we find
that this small organ is about the shape and size of the wing
of the insect on which it feeds. The beat of the insect's
wings is communicated to this organ and enables the bat to
follow the insect and seize it without seeing it. This is very
simple and easily understood, because the insect itself produces
certain atmospheric vibrations to which the little leaves in
front of the bat's ear respond, but, when we come to in-
animate things that give off no vibrations of themselves, how
does the bat know of their presence ? How is it able to
judge of their character ?

It has already been shown that the wings of the bat are
extremely sensitive and very well provided with nerves, and
the same is true of the various, organs on the face; of course,
all of these are intimately connected with each other, and
.ilso with the brain of the bat. '(When a bat flies about in
total darkness, the beat of its wings sends out a series of pul-
-sations or waves after the manner of sound waves, but of
too low a frequency to be considered as sound. These waves
strike against all surrounding objects, and, like sound or light,
are reflected back to their source of origin] The wings send
out ,.uns or impulses and they are reflected back

and i«^~ivcd by the sensitive organs which form a part of
the face of the bat. lThe extremely delicate nature of the
bat's wings, together with the sensitiveness of its organ of the

c 17

A New System for Preventing Collisions at Sea

sixth sense, enables it to judge the distance to any object
by the lapse of time between the sending out and the receiving
of the waves, because it takes some time, some fractional part
of a second, for a wave to travel from the bat's wings to
the object and return to the bat's face^

We know that this is the mechanism that gives to the bat
what is practically a sixth sense. We know it must be true
because it cannot be otherwise. That the bat possesses this
power is completely beyond dispute, and this is the only way
that it can be accomplished. But all bats do not possess this
organ ; the fruit-eating bats that do not fly about in total
darkness have large eyes and never possess this organ, although
in some cases, we find the rudimentary remains of the organ
which they have inherited from their early ancestors, the same
as we have inherited the Darwin tip.

Anyone who has made a study of heat, light and sound, and
is familiar with the experiments of Professor Tyndall, must be
struck with the similarity of the laws that govern these three
forms of energy. If the atmosphere is very clear, the search-
light will reveal objects at a considerable distance. In this case,
let us see what takes place. The carbons in the lamp become
intensely heated and send off certain very rapid waves in the
ether. These travel with a marvellous rapidity, strike the
object, become modified to some extent, and a portion of them
returns and enables us to distinguish the object. It will, there-
fore, be seen that it is the waves that we send out that return
to us. If we go into a dark room with a candle, these same
ether waves are sent out in all directions ; everything in the
room becomes] illuminated, and the waves that return to our
eyes enable us to know exactly what the room contains.

18

A Sixth Sense

Every little detail is revealed with the greatest degree of
nicety. In like manner the bat, on going into a perfectly
dark cave where there is not the least suspicion of light,
produces certain kinds of vibrations with its wings ; these
vibrations or waves are sent out exactly the same as the ether
waves sent out by the candle. Everything in the cave is
struck by these waves, and everything that is struck reflects
back to the bat a portion of the waves that it receives exactly
as is the case with the light. In this manner, the bat is able
to move about with perfect ease exactly as a bird would do
if the cave were brilliantly illuminated. Of course, this system
of detecting objects, and of judging of their character arid size,
although sufficient to answer the purpose of the bat per-
fectly, cannot be compared at all with the waves that are
sent out by a candle and received by our eyes.

It is very evident from the foregoing that bats which
are able to fly about in total darkness, very much as birds
do in daylight, do not depend upon their eyes or their ears,
but have some other means of detecting the presence and
locality, also the character, of objects — that is, they have a
sense which is neither hearing nor seeing, and the organ of
this sense is situated on the face of the bat. The extra-
ordinary formation on the face of Blainville's Bat enables
this animal to fly about in absolute darkness, avoiding all
possible obstructions which may be placed in its path.
These evolutions could not be performed without the aid of
a sixth sense. I do not think it will be disputed that these
animals do have a sixth sense.

Some small insects, such as mosquitoes, bees, and certain
kinds of flies, produce a musical note with their wings ; the

19

A New System for Preventing Collisions at Sea

humming bird also moves its wings with sufficient rapidity to
produce an audible musical note. In many kinds of beetles,
the wings are not moved rapidly enough to produce an
audible note, but every insect or bird that flies does produce
atmospheric vibrations which are identical with sound and
are governed by the same laws, the only difference being that
the formation of our ears is such that they are unable to
respond to such very low notes. This, however, does not
prove their non-existence ; it shows rather the limitation of
our ears. It requires sixteen pulsations or vibrations of the
air in a second of time to produce the deepest bass note
that we are able to hear and which corresponds to the note
given off by a 32-foot organ pipe.

As a rule, the bats that are provided with the sixth sense
are very small, and it is probable that they only make about
ten to twelve strokes with their wings in a second of time.
This, of course, produces an extremely low note that does
not appeal to our ears, but it travels after the manner of
sound — or light, for that matter — strikes all of the surround-
ing objects, becomes modified by their character and size,
and is reflected back, and these reflections or echoes are
received by the organ of the sixth sense and analysed, exactly
the same as light waves would be by our eyes under
similar conditions. It is, therefore, certain that the bat obtains
its knowledge of surrounding objects by sending out certain
atmospheric vibrations and receiving back in a fraction of a
second later, the reflected and modified vibrations.

This is a purely mechanical problem. From the foregoing, I
think its action will be understood, and I do not think it will
be denied that we can imitate it to some extent mechanically.

20

A Sixth Sense

The energy employed by the bat is certainly not more
than one - thousandth part of a horse-power, but it serves
the bat's purpose perfectly well.

Suppose, now, that we construct an apparatus that will
produce atmospheric vibrations of about the same frequency
as those produced by the bat, but instead of using the
infinitesimal amount of energy employed by the bat, we
use two or three hundred horse-power — that is, we send out
waves that have an amplitude and energy at least three hundred
thousand times as great as those sent out by the bat. These
vibrations, although of great energy, will not be audible to
our ears, but they will shake up and agitate light objects
for a considerable distance, and 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 send back to the ship a reflected
echo that would be strong enough to be detected.

The quantity of steam required would not be very great,
because the valve would not be opened very often, and
when open wrould not remain open more than a second at
a time ; therefore, the total amount of steam required while
signalling was actually going on would certainly not exceed
ten horse-power.

The apparatus could also be used for communicating with
other ships by giving off long and short blasts representing
the dots and dashes of the Morse system.

21

THE APPLICATION OF THE SIXTH SENSE
TO SHIPS

HAVING ascertained that the bat does possess a sixth sense,
and having discovered the organ that makes this sense pos-
sible, let us see now if we cannot accomplish the same thing
in a rough sort of a way on a large scale for use on steam-
ships at sea.

The human ear has a range between the note that is given
off by a | -inch organ pipe and by one 32 feet long, but
the sound given off by a J-inch organ pipe is not audible to
us because the sound waves are too frequent ; there is
nothing in our ears that is able to respond to them, whereas
the note given off by a 33-foot organ pipe has not a sufficient
number of vibrations in a second to bring it within the
range of our ears. Low notes travel much farther than high
notes. The American bull-frog, which is about the size of a
man's fist, emits a deep bass note which can easily be heard
at a distance of two miles — some writers say three miles.

It is known that whales are able to communicate with
each other over vast distances by some species of low
bellowing, but the note given off is too low to have any
effect on the human ear.

At the age of thirteen, I discovered that the common mouse
is quite unable to hear the voice of a man, but it is able to
hear the voice of a woman, in which the number of vibrations
per second is about four times as great as in a man's voice.

22

The Application of the Sixth Sense to Ships

About one-half of mankind is able to hear the high note
given off by crickets, and the same is true of the voice of bats.
Extremely high notes have very little power ; they do not
travel far enough to be of any use at sea.

In providing a ship with a sixth sense, we have to con-
sider three distinct devices : one for producing and sending
out the necessary waves, one for receiving the reflected
waves and making them audible by ringing bells, and
another apparatus for recording the amplitude of the waves.

For producing the vibrations of waves, I prefer to use a
modified form of a siren, the disc being rotated at a suitable
speed by a motor of some kind, preferably an electric motor.
I prefer to use a very high pressure of steam, to have
all the parts large and strong, and to produce about fourteen
or fifteen vibrations per second. These will not come within
the range of the human ear, consequently they cannot be
considered as sound, and as they are of great amplitude and
power they are able to travel over great distances, and
when they come in contact with a body, the waves are
reflected back to the ship in the same manner. that sound
would be reflected back, but this echo would not be audible
to the human ear. I, therefore, provide an apparatus which
might be considered as an artificial ear. It 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 waves of the echo, and its vibrations are made to open
and close certain electrical circuits which ring a series of bells
of various sizes. If, for example, the object is very small

23

A New System for Preventing Collisions at Sea

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.
This apparatus gives an audible notice if anything is ahead
of the ship.

The other apparatus is similar, but instead of ringing a bell
it 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 seawaves, a wavy line is produced, 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 (see frontispiece), 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 ; therefore, the distance
can be determined with a considerable degree of nicety, and
the size of the object may be determined by the amplitude of
the waves that return.

Very extensive experiments were conducted about forty years
ago by Professor Tyndall at the South Foreland. He found
that a deep note emitted by a powerful siren travelled a very
long distance, and he was rather surprised at the volume of
sound that was reflected back from a ship. At that time it
was generally supposed that snow, rain, and fog were very un-
favourable to the travel of sound, but in his experiments he
found that such was not the case. I quote the following from
his work on " Sound " : —

u Rain has no sensible power to obstruct Sound.
" Hail has no sensible power to obstruct Sound.
<4 Snow has no sensible power to obstruct Sound.
" Fog has no sensible power to obstruct Sound."

24

The Application of the Sixth Sense to Ships

" The air associated with fog is, as a general rule, highly homo-
geneous and favourable to the transmission of sound. The notions
hitherto entertained regarding the action of fog are untenable."

The most unfavourable weather for sound is when the sun
is shining brightly and when the air is optically perfectly clear.
Under these conditions, we have heated air rising up from the
earth, and cooler air descending ; this produces a kind of a
glimmer in which it is very difficult to sight a gun at long range
with any degree of exactness, but my apparatus would not be
needed in this kind of weather.

It is well known that the air around a large iceberg is
extremely cold — in fact, so cold that certain scientific men have
thought that it might be possible to detect the presence of
icebergs by the use of a delicate thermometer ; but the cold
air does not extend far enough around the iceberg to make this
practical. Cold air, however, lends itself admirably to the use
of my apparatus, because the air itself about the iceberg, being
of a different density from the surrounding air, acts as a re-
flector returning the vibrations to the ship.

In Professor Tyndall's experiments I find the following : —

" In the experiments at the South Foreland, not only was it
proved that the acoustic clouds stopped the sound, but that the
sounds which had been refused transmission were sent back by
reflection."

SOME REMARKS ON THE OPERATION AND
USE OF THE APPARATUS

THE apparatus for producing the atmospheric vibrations should
be placed well forward on the main deck or in any other
position where it can be turned about from port to starboard.
It should be very firmly secured to the deck, and connected
with a high-pressure boiler by a three-inch pipe. A straight-
way valve should be placed in the pipe near the boiler, and
means should be taken to prevent accumulation of water in
the pipe leading to the apparatus.

Of course, there would be no use for the apparatus except
in dark, foggy or stormy weather, unless it was to be used
for communicating with other ships. When, however, the
presence of other ships or icebergs is suspected at night, the
apparatus should be used constantly, sending out the blasts
in every direction. If the sea were perfectly clear, the blasts
sent out would be recorded at the very instant of their pro-
duction, but no echo would be returned other than that due
to the waves of the sea, which would produce a zigzag line
of small amplitude ; 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 should be always the
same, it would indicate the presence of some object, and the

26

The Operation and Use of the Apparatus

length of paper between the primary blast and the echo would
indicate the distance that the object was from the ship. It
might be so arranged that one inch of paper represented a mile.

The receiving instruments can be placed anywhere on the
ship where they can be turned in the same direction that
the siren is turned, and there may be as many of them as
desirable.

Of course, there are vastly more accidents caused by
running ashore than by collisions at sea, and it does not
require a very bold sea front to produce a very strong echo.
For example, in approaching the coast of Ireland, the echo
would be sufficiently strong to show itself over a distance of
at least ten miles.

To many it will doubtless appear very difficult, even on the
verge of the impossible, to reveal the presence of objects at sea
by simply sending out atmospheric vibrations and receiving
the echo of the same. One might ask, how can it be possible
to judge of the size, distance, and character of the object
by the echo ? If, however, we make a careful study of the
matter, we shall find, if we send out a powerful blast of
sound like a deep musical note, that it will travel a long
distance, and if it strikes any object of considerable size, it
will send back a reflection or echo. Sound is nothing more
nor less than atmospheric vibrations. If there are less than
sixteen vibrations in a second of time, they are not audible
to our ears; we do not hear them, although we may feel
them. They may be of great power and able to travel a
long distance, and if they should happen to strike any
object they send back an echo which, although completely
inaudible to our ears, is sufficient to record itself by suitable

27

A New System for Preventing Collisions at Sea

apparatus, and the record thus made will give us a fair idea
of the object struck. It will indicate its size and shape
with a fair degree of accuracy ; it will indicate its direction
from the ship, and will also show its distance with great
accuracy. It will distinguish a ship from an iceberg, will
show whether the object is stationary or moving, and if
moving the direction and velocity of such movement.

Before describing fully the modus operandi of this apparatus,
we will first examine some of the phenomena relating to sound
and the accompanying echo.

On one occasion I witnessed a stroke of lightning at a
distance of ten feet. It was simply a blinding flash and a
short, sharp, ear-piercing snap ; I did not hear any thunder.
The duration of a flash of lightning is only a small fraction
of one-thousandth part of a second, and still we hear the
thunder roll for some seconds, perhaps ten or more. All the
noise is produced in less than one-thousandth part of a second.
The thunder is not the direct sound, but the echo, which varies
greatly, according to the character and distance of the object
that reflects the primary sound. On one occasion, while on
the very roughest part of the Tete Noire, we were overtaken
by a very violent and noisy thunderstorm. There were many
large objects all around us, and each flash of lightning was
followed by noises coming from all directions and resembling
musketry fire. The clatter was so great that I failed to hear
a " thunder roll " of the kind so well known in all level
countries and at sea. The rolling and reverberating sound
known as thunder that follows a lightning flash is all made
up of echoes. The first short sharp primary snap sends out
vibrations that strike the clouds ; if the clouds were solid and

28

The Operation and Use of the Apparatus

hard the echo would also be sharp and short, but as the
clouds only vary slightly in density from the surrounding
air, the sound is much modified and softened — that is, par-
taking in no small degree of the nature of the reflecting body.
Clouds are of all densities and are at various distances. The
primary vibrations produced by the lightning are echoed and
re-echoed between the clouds and the earth, producing a very
complicated series of sounds of widely varying degrees of
intensity. Thunder is a reflection that reveals the character
of the object in our vicinity. Would not a blind man with
good ears and a knowledge of the laws of sound as relates
to thunder be able to judge something of the nature of his
surroundings by the character of the thunder ? In the system
of Zadig described by Voltaire, we find what a lot of infor-
mation one is able to obtain from very slender data. The
same idea is elaborated by Sir Conan Doyle in his " Sherlock
Holmes." In my apparatus, we have to examine certain little
zigzag lines on a strip of paper ; the relative size of the zig-
zags, their position on the paper, and their number, can be

read and understood without the use of anything approaching

•

the skill of Zadig or Sherlock Holmes. In order to bring
this subject within the grasp of all, let us suppose a case.

We will imagine that all ships of any considerable size
crossing the Atlantic are provided with my apparatus. We
embark on one of these ships at New York at 4 o'clock in
the afternoon, and a few hours later we are well out on
the Atlantic in a moderate sea way, and adjust our receiver
so that the small bell sounds about every ten seconds, due
to the noise of the wind and waves. We try our recording
instrument, and find that it only produces a wavy line, quite

29

A New System for Preventing Collisions at Sea

uniform. We next send out a powerful blast, and find that
this has produced a decided series of zigzag lines on the
strip of paper. The bells have not sounded because the
electric current that rings them is cut off by the act of
opening the steam valve of the siren. Nothing is on the
paper except the marks produced by the primary blast and
the sea waves. We repeat our experiment by pointing our
instruments a few degrees to both port and starboard ; still
no result. Therefore there is evidently no large object ahead
of us, and we proceed in the darkness at 'full speed, repeat-
ing our experiments every ten minutes if the weather is
foggy. At about midnight, we find a very faint indication
of an echo ; the wavy line due to the sea is slightly
modified when our instruments are pointed ten degrees to
the port, but not when pointed dead ahead or to the star-
board. We repeat at the port side with the same result as
before, but we find that the little bell of the indicator shows
an increased ringing, and a few seconds after we send out
our blast from the siren, or vibrator, as we should call it.
The echo reaches us 20 seconds after sending out the blast ;
consequently, it took 10 seconds for our vibrations to reach
the object and another 10 seconds for the reflected vibrations
to return ; therefore, the distance is slightly over two miles.
Our ship is doing 20 miles per hour, and 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
dead ahead, also that the distance between the object and
our ship is being reduced at the rate of 35 miles per hour ;
therefore the unknown object is evidently a ship making 15

30

The Operation and Use of the Apparatus

miles per hour, and travelling towards 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 in 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
seen the ship, but we have a fair idea of her ; we know
her speed and the direction in which she is sailing.

The next day is fine and clear ; we meet several ships and
send out blasts and note the readings. Amongst these ships
is a large fully rigged sailing ship with all sail on. When
she is off our beam, we turn our indicator and recorder in
her direction and send out a strong blast of two seconds'
duration ; this is followed in six seconds by a ringing of all
our bells, and the recorder has a clear record showing that
the object sending back the waves or vibrations is of great
size and high out of the water.

We are now off the New England coast ; night is coming
on and there is a slight mist, so that a ship's lights cannot
be seen more than half a mile distant. Suddenly the two
smaller bells at our indicator ring violently ; we have not
sent out a blast, and so we know it is the blast from another
ship's vibrator. We answer by a blast and then liberate the
clockwork, so that the paper strip is fed out continuously,
and very soon our recorder shows the letters A B C to be
followed by a message and a reply. The ships are now 30
miles apart, and we find that the primary blast will work
our recorder at that distance, or more than twice as far

A New System for Preventing Collisions at Sea

as the echo ; 45 minutes later we send out a blast and receive
a faint echo which tells us that the ship is ten miles distant.
A few minutes later the echo is very strong, makes a decided
record, and rings our smallest bell. We make other records
as the ship approaches, and when she is off our port beam,
broadside on and only half a mile distant, she sends us a
blast that we can feel if not hear. It rings all our bells
violently, and causes every light object on the deck to vibrate.

The following day we only exchange messages with other
ships ; night comes on, we encounter a dense fog and by mid-
night are on the Banks of Newfoundland. We are constantly
sending out blasts without receiving any response. However, at
about two o'clock in the morning, we do receive a response ; it is
only slight and only a short distance away, so we know it is
some small object, which we soon pass without seeing it, 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. When daylight appears, we
are still in a dense fog ; we make out and communicate with
several ships that have our apparatus, but we fail to see any of
them. About nine o'clock in the morning we have a new ex-
perience ; we send out a blast and receive back an echo showing
that there is an exceptionally large object very nearly dead
ahead of us. We know it 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

32

The Operation and Use of the Apparatus

is stationary. When we are two miles apart, the reflection of
our blasts rings the bells, and the indicator shows a different
record to 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 tailing out of spots made by the zigzag lines. The total
length of the echo is thus made longer than that pro-
duced by the primary blast. This shows that there is
some kind of a cloud about the object of a different density
from the surrounding air and that it is of considerable size.
Therefore, we draw a logical conclusion. 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 pass 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 of ice that
have been broken off. The following day we pass many ships,
and with our apparatus we inform them of the size and
locality of the big iceberg. We are now well off the Banks,
but still in a locality where icebergs may be found, and in
the afternoon we come in sight of a group of these danger-
ous objects of all sizes. We give them a blast and the record
produced is peculiar. Instead of one spot of zigzag lines
on the paper strip, there are about half a dozen spots. Each
iceberg within range has made its own record, indicated
roughly its size and accurately its distance. Soon night is
on us again, accompanied by a slight mist that obliterates
D 33

A New System for Preventing Collisions at Sea

the lights of passing ships. At about nine o'clock, after
sending out many blasts to port and starboard, and also
dead ahead, we have a very slight indication that there is
some large object ten miles distant, and very nearly in the
direction we are going. We expect to get a stronger reading
in a few minutes, but do not do so. However, we keep on
sending out blasts, and at the end of an hour the readings
are more distinct and the distance is reduced from ten miles
to seven, showing that the object in question is evidently a
ship going in the same direction as ourselves but at a lower
speed. We come up to her and pass her in a short time ; we
next find that there is a very large object off our starboard
beam. Our recorder shows the distance to be over twelve
miles, and still the markings are quite distinct. What can
it be ? Reason tells us that it is a big liner with her
immensely large broadside in a position to send back to us
an echo such as we have never received before at such a
distance. We continue sending out blasts, and soon find
that the big ship is going in the same direction as ourselves,
and at a speed of fully three miles an hour faster than our
own ship is travelling. In a short time she is so far ahead
of us that we cannot receive back an echo.

The day following is very fine and cloudless ; the sun shines
down from a deep blue sky with remarkable intensity. There
is practically no wind. However, at about midday, the little
wavelets on the surface of the water show that the air is in
motion. Currents of cold air are descending, spreading out
over the surface of the water, and producing the little waves
that enable us to locate both the descending and ascending
currents. The warm air produced by the intense heat of the

34

The Operation and Use of the Apparatus

sun shining on the surface of the water is constantly rising and
its place being taken by the colder air above. It is like the
rush of the third-class passengers through the rushing first class
at a railway station. This of course produces a great many
conflicting currents of aii of different densities, certainly very
favourable for the production of acoustic clouds ; optically the
air is clear and transparent. At two o'clock we send out blasts
in various directions, and, although there is nothing in sight,
we receive responses of considerable power, showing unmistak-
ably the presence of invisible acoustic clouds. The readings
on the paper strip, however, are drawn out and much longer
than the primary blast. Acoustic clouds never appear in foggy
weather ; they are produced by many conflicting currents of air,
of different densities, the result of bright and unobstructed
sunshine.

The last three days of our voyage are cloudy, rendering
observation impossible. It is a very dark and foggy night,
and we are approaching the rugged coast of Ireland. We work
our vibrator constantly, sending out strong blasts every few
seconds, but we receive no response until near morning. We
know that there is no danger, as our apparatus shows that the
coast is clear, so we keep on full speed until we receive some
response to our blasts. The first is very feeble and comes from
a distance ; twenty minutes later the record is strong and
distinct, and there is more than one record. Some objects are
only three miles distant and of no great size, whilst others are
indicated fully ten miles distant, and from the size and shape of
the records must be of great size. It is the uneven coast of
Ireland, with mountains in the background. The fog continues
dense ; still, with our apparatus we are able to skirt the coast,

35

PLATE 1. — Vertical Central Section of the Apparatus for Producing the Vibrations.

The Operation and Use of the Apparatus

keeping our distance from the shore, and have no difficulty of
feeling our way into port.

Plate No. i represents a vertical central section of the appar-
atus for producing the vibrations. The rotating disc is driven
at a uniform speed by an electric motor, so that the pitch of the
note sounded is always the same. The steam enters the central
pivot, passes through the balanced valve, and escapes through

PLATE 2. — Side Elevation of the Siren or Vibrator.

expanding nozzles into the small end of the trumpet. The
balanced valve is opened and closed by means of a handle, as
will be seen ; the opening and closing of the valve also makes
and breaks electric circuits.

Plate No. 2. — A side elevation of the complete apparatus
on a greatly reduced scale. The trumpet, being of great
size, is supported by a wheel. The trumpet may be turned
in any direction without interfering with the supply of steam,
which enters through the centre of the pivot on which the
apparatus revolves. It is proposed to use this form for long-
distance work, but where it is desirable to spread the vibra-

37

A New System for Preventing Collisions at Sea

tions out and to occupy more territory, a much shorter
trumpet is employed, which is bell-mouthed and does not
require any support other than the central pivot,

Plate No. 3. — A vertical central section of the apparatus for
converting the inaudible waves of the echo into sounds which
are audible to the human ear. This apparatus is provided with
a thin, tightly drawn diaphragm. The atmospheric vibrations
cause this diaphragm to vibrate after the manner of the head
of a drum, and in moving it opens and closes electrical circuits
and causes bells of various sizes to ring. The circuit making
and breaking apparatus is shown in the smaller illustration.
Any degree of fine adjustment may be made by means of
the spindle, which is provided with a screw thread passing
through a support inside of the cylinder. Whatever pressure of
air there may be on the front of the diaphragm produces a
similar pressure inside of the cylinder. The air passes through
the felt, and through a small opening that is adjustable in the
connection through which the screw spindle passess.

In Plate No. 4 we have a vertical central section of the
apparatus for recording the frequency and the amplitude of the
atmospheric vibrations that strike the diaphragm. A very
small and light rod is attached to the centre of the diaphragm
which passes to the rear and carries a pencil point that records
the vibrations on a strip of paper similar to trjat used in a
Morse instrument. When the operator moves the handle of
the siren downward, he not only opens the steam valve, but
closes an electric circuit which releases the mechanism of the
Morse instrument and allows about fourteen inches of the paper
to be fed out, all of which is shown in the drawings.

The primary blast sent out by the siren is registered on the

38

Tl

PLATE 3. — Receiver that Makes and Breaks Electrical Circuits for Ringing Bells.

PLATE 4. — Receiver for Recording the Vibrations.

The Operation and Use of the Apparatus

paper strip, and the distance that the object is from the ship
may be determined by the distance between the record of the
primary blast and the echo received, as shown in the drawing.

PLATE 5.— System of Mounting the Receivers.

Observe the markings on the strips of paper shown at the top
of the drawing.

Plate No. 5. — Some engineers might imagine that it would
be very difficult to mount these delicate instruments on a
vibrating ship so as not to interfere with their fine adjustment

A New System for Preventing Collisions at Sea

and accurate working, but this trouble is overcome by mount-
ing them as shown in Plate 5. They are placed inside of a
large hoop and suspended by eight pure rubber straps. This
effectually prevents them from participating in any of the
vibrations that are peculiar to a high-powered ship.

At a mean temperature of 50° F. sound travels 1,100 feet
in a second of time. It takes sound 4.8 seconds to travel
one mile and 9.6 seconds to reach an object one mile distant
and send back an echo.

The guns of H.M.S. Thunderer were recently heard at
a distance of 100 miles.

42

ICEBERGS

IN many cases, icebergs are of immense size, and they are
always slowly melting. Many have supposed that it would
be possible to detect their presence by a change in the tem-
perature of the water, but nothing could be farther from the
truth.

At the spot where the Titanic went down the water is
over two miles in depth. Water, being a non-conductor
of heat, can only be cooled or heated by convection — that
is, in order to be cooled it must touch something that is
cold. About eight-ninths of the bulk of an iceberg is below
the surface of the water, and only one-ninth above. As the
sea water comes in contact with the ice, a certain portion
of the ice is dissolved, and each pound of it that is dissolved
absorbs heat enough from the surrounding sea water to
raise one pound of water 140° — that is, it requires 140
British thermal units to melt one pound of ice. This is
very considerable, and causes a downward current of the
sea water and what little fresh water has been melted from
the ice, so that with a large iceberg the relatively warm
water of the sea is flowing from all sides towards the ice-
berg, and as it comes in contact, it is cooled, sinks, and other
water is drawn into its place. Thus the iceberg is constantly
being diminished in size, but it does not chill the surface of the
water to any considerable extent. If the water about an

43

Icebergs

iceberg is colder than the surrounding water, it will certainly
sink, and its place be taken by other water which has not
been chilled. It will, therefore, be seen that the testing of
the water at any considerable distance from an iceberg can
be of little or no use.

With the air, however, it is quite different. The ice-
berg is never moving as relates to the water, it is always
travelling with the water and at the same speed, but the
air is always travelling as relates to the iceberg. The result
is that a very large quantity of air is chilled by passing
over the iceberg, and this forms a bank of air at the lee-
ward of a greater density than the surrounding air, and this
of itself is capable of reflecting sound or the kind of vibrations
which I employ in my apparatus.

I am very strongly of the opinion that the thermometer,
either in the air or in the water, can be of very little use,
whereas my apparatus not only detects the presence of an
iceberg, but it indicates its approximate direction from the
ship, and measures the distance with a high degree of
accuracy. Moreover, my apparatus lends itself admirably
for transmitting messages, providing the distance is not
greater than twenty miles.

Suppose two ships, each provided with my apparatus, should
wish to communicate, it is only necessary that the recording
apparatus should be turned in the direction of the ship and
the mechanism allowed to feed out the strip of paper. We
should then be able to dispatch and receive messages, using
the Morse code — a short blast for the dot and a long blast for
a dash. In like manner a ship would be able to communicate
with the shore, providing the distance was not too great.

45

A New System for Preventing Collisions at Sea

In conclusion, I would say that, as steamships are always
provided with plenty of steam power, there is no reasonable
limit to the size of the apparatus that may be used. It may
be possible to send out a series of pulsations that will travel
over a distance of 100 miles and be received by the delicate
apparatus which I prefer to call a " recorder."

In this little booklet, I have only shown devices that are
easily understood by the unscientific. For producing the
primary vibrations on the ship I use a modified form of a
siren, with certain improvements that make it much more
powerful than those now in use. For receiving the echo,
I have shown two separate devices — one that rings a series
of bells of assorted sizes according to the intensity of the
echo, and another for recording the echo and showing, in a
very graphic manner, the distance that the object is from the
ship. In both of these, I employ a simple diaphragm stretched
over the head of a cylinder after the manner of a drum,
and it is the vibrations of these diaphragms that open and
close the electrical circuit that rings the bells in the one
case, and in the other case produces zigzag lines on a strip
of paper.

Full and complete working drawings have been made of all
of these devices, and, of course, these large, coloured drawings
are much easier to understand than the very small illustra-
tions which form part of this booklet. However, if interested
parties wish to see the large drawings, I am prepared to
show them.

The apparatus will work exactly as described with the
devices already designed, but I am not going to rest at this
point. I shall shortly produce a recording instrument with

46

Icebergs

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.*

Experiments without Cruelty.

It is quite possible that what I have written will lead
investigators to make experiments on Bats. I therefore
suggest how these experiments may be conducted without
cruelty.

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 eyes do not reveal the
presence of glass. The result is, a broken neck and instant
death.

Suppose now that we make the same experiment with a
Bat. Before the Bat is liberated it does not perceive the
glass, it simply appears to be an opening through which it
cari escape, exactly as was the case with the bird, and like
the bird, when liberated it makes a rush to escape. The
flapping of the wings brings its sixth sense into action and
it soon perceives that it is face to face with a solid wall. It
stops short before it touches the glass, but as its eyes tell it
that the road is clear it is naturally greatly puzzled and
continues to face the glass without touching it for some
time. However, it places much more reliance on the sixth
sense than on the sense of sight, otherwise its fate would be
the same as that of the bird.

Naturalists have made this experiment, and those that
will not admit that the Bat possesses a sixth sense will
perhaps explain this phenomenon.

The bird found the glass by the sense of feeling, which
is defined in the dictionary as "the sense of touch," with
fatal results. The Bat found it by a sense which is not
possessed by other animals — what shall we call this sense ?

HIRAM S. MAXIM.
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