TH E RO/nANCE
OF WAR
INVENTIONS
S.JW
THE IAN HARDY SERIES
BY
COMMANDER E. HAMILTON CUEKBY, R.N.
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IAN HARDY, NAVAL CADET
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IAN HARDY, SENIOR MIDSHIPMAN
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IAN HARDY FIGHTING THE MOORS
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THE ROMANCE OF WAR INVENTIONS
A TANK.
These weird-looking engines are literally moving forts, and are the evolution of a peacefu
agricultural machine fitted with "caterpillar" wheels, that is, a broad band encircles the
driving wheels, and so the whole construction moves as it were on its own revolving platforn
ind is thus prevented from sinking into the soft ground.
vas adapted to transport carts during the Crimean War.
ig pla
The principle itself is not new, as
JHE
ROMANCE
OF
WAR INVENTIONS
A DESCRIPTION OF WARSHIPS, GUNS, TANKS,
RIFLES, BOMBS, AND OTHER INSTRUMENTS
AND MUNITIONS OF WARFARE, HOW
THEY WERE INDENTED fc? HOW
THEY ARE EMPLOYED
^ BY
T. W. CORBIN
AUTHOR OF " THE ROMANCE OF SUBMARINE ENGINEERING,"
"MECHANICAL INVENTIONS OF TO-DAY,"
&c., fife., &c.
With many Illustrations
LONDON
SEELEY, SERVICE far CO. LIMITED
38 GREAT RUSSELL STREET
1918
j-
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By Prof. G. F. SCOTT ELLIOT, M. A.. B.Sc.
The Romance of Savage Life
The Romance of Plant Life
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The Romance of Modern Sieges
By JOHN LEA. M.A.
The Romance of Bird Life
By JOHN LEA. H.A. 6 H. COUPIN, D.Sc.
The Romance of Animal Arts and Crafts
By SIDNEY WRIGHT
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By the Rev. J. C. LAMBERT, M.A., D.D.
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By G. FIRTH SCOTT
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By CHARLES R. GIBSON, F.R.S.E.
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The Romance of the Spanish Main
SEELEY, SERVICE ^ co., LIMITED.
CONTENTS
IHAPTBR PAG
I. How PEACEFUL ARTS HELP IN WAR . .17
II. GUNPOWDER AND ITS MODERN EQUIVALENTS . 27
III. RADIUM IN WAR 39
IV. A GOOD SERVANT, THOUGH A BAD MASTER . 49
V. MINES, SUBMARINE AND SUBTERRANEAN . . 61
VI. MILITARY BRIDGES 75
VII. WHAT GUNS ARE MADE OF . . .92
VIII. MORE ABOUT GUNS 108
IX. THE GUNS THEY USE IN THE NAVY . . 120
X. SHELLS AND HOW THEY ARE MADE . . .135
XI. WHAT SHELLS ARE MADE OF . . . .146
XII. MEASURING THE VELOCITY OF A SHELL . . 159
XIII. SOME ADJUNCTS IN THE ENGINE ROOM . .164
XIV. ENGINES OF WAR 169
XV. DESTROYERS 184
XVI. BATTLESHIPS 191
XVII. How A WARSHIP is BUILT . 202
14 CONTENTS
CHAPTKR PACK
XVIII. THE TORPEDO 215
XIX. WHAT A SUBM\RINE is LIKE .... 223
XX. THE STORY OF WIRELESS TELEGRAPHY . . 240
XXI. WIRELESS TELEGRAPHY IN WAR . . .252
XXII. MILITARY TELEGRAPHY 264
XXIII. How WAR INVENTIONS GROW . . .276
XXIV. AEROPLANES 284
XXV. THE AERIAL LIFEBOAT 297
INDEX .... . 313
LIST OF ILLUSTRATIONS
A TANK Frontispiece
PAGB
MACHINE-GUN VERSUS RIFLE 32
AN ITALIAN MINE-LAYER 64
AN INCIDENT AT Loos 80
AN IS-POUNDER IN ACTION 96
A GERMAN AUTOMATIC PISTOL 112
BOMB THROWING 136
BOMB-THROWERS AT WORK 160
THE TRIPOD MAST 208
LISTENING FOR THE ENEMY 248
DIAGRAM SHOWING THE PRINCIPLE BY WHICH THE AERIALS
ARE CONNECTED TO THE APPARATUS . . . .251
THE PARENT OF THE TANK 280
THE "GUARDIAN ANGEL" PARACHUTE. . . . 304
'5
THE KOMANCE OF WAK
INVENTIONS
CHAPTER I
HOW PEACEFUL ARTS HELP IN
WAR
IN the olden times warfare was supported by a
single trade, that of the armourer. Nowadays
the whole resources of the greatest manu-
facturing nations scarcely suffice to supply the needs
of their armies. So much is this the case that no
nation can possibly hope to become powerful in a
military or naval sense unless they are either a great
manufacturing community or can rely upon the
support of some great manufacturing ally or
neutral.
It is most astonishing to find how closely some of
the most innocent and harmless of the commodities of
peace are related to the death-dealing devices of war.
Of these no two examples could be more striking
than the common salt with which we season our food
and the soap with which we wash. Yet the manu-
facture of soap furnishes the material for the most
B 17
HOW PEACEFUL ARTS HELP IN WAR
furious of explosives and the chief agent in its manu-
facture is the common salt of the table.
Common salt is a combination of the metal sodium
and the gas chlorine. There are many places, of
which Cheshire is a notable example, where vast
quantities of this salt lie buried in the earth.
Fortunately it is very easily dissolved in water so
that if wells be sunk in a salt district the water
pumped from them will have much salt in solution
in it. This is how the underground deposits are
tapped. It is not necessary for men to go down as
they do after coal, for the water excavates the salt
and brings it to the surface.
To obtain the solid salt from the salt water, or
brine as it is called, it is only necessary to heat the
liquid, when the water passes away as steam leaving
the salt behind.
Important though this salt is in connection with
our food, it is perhaps still more important as the
source from which is derived chlorine and caustic
soda. How this is done can best be explained by
means of a simple experiment which my readers can
try in imagination with me or, better still, perform
for themselves.
Take a tumbler and fill it with water with a little
salt dissolved in it. Next obtain two short pieces of
wire and two pieces of pencil lead, which with a
pocket lamp battery will complete the apparatus.
Connect one piece of wire to each terminal of the
battery and twist the other end of it round a piece
of pencil lead. Place these so that the ends of the
leads dip into the salt water. It is important to keep
18
HOW PEACEFUL ARTS HELP IN WAR
the wires out of the solution, the leads alone dipping
into the liquid, and the two leads should be an inch
or so apart.
In a few moments you will observe that tiny
bubbles are collecting upon the leads and these
joining together into larger bubbles will soon detach
themselves and float up to the surface. Those which
arise from one of the leads will be formed of the gas
chlorine and the others of hydrogen.
It will be interesting just to enumerate the names
of the different parts of this apparatus. First let me
say that the process by which these gases are thus
obtained is called electrolysis : the liquid is the
electrolyte : the two pieces of pencil lead are the
electrodes. That electrode by which the current enters
the electrolyte is called the an-ode, while the other is
the cath-ode. In other words, the current traverses
them in alphabetical order.
Now it is familiar to everyone that all matter is
supposed to consist of tiny particles called Molecules.
These are far too tiny for anyone to see even with
the finest microscope, so we do not know for certain
that they exist : we assume that they do, however,
because the idea seems to fit in with a large number
of facts which we can observe and it enables us to
talk intelligibly about them. We may, accordingly,
speak as if we knew for a certainty that molecules
really exist.
Now when we dissolve salt in water it seems as if
each molecule splits up into two things which we
then call " ions." Salt is not peculiar in this respect,
for many other substances do the same when dis-
19
HOW PEACEFUL ARTS HELP IN WAR
solved in water. All such substances, since they can
be " ionized," are called " ionogens."
Now the peculiarity about ions is that they are
always strongly electrified or charged with electricity.
At this stage we must make a little excursion into
the realm of electricity. You probably know that if
a rod of glass be rubbed with a silk handkerchief it
becomes able to attract little scraps of paper. That
is because the rubbing causes it to become charged
with electricity. In like manner a piece of resin if
rubbed will become charged and will also attract
little pieces of paper. A piece of electrified resin and
an electrified glass rod will, moreover, attract each
other, but two pieces of resin or two pieces of glass, if
electrified, will repel each other. This leads us to
believe that there are two kinds of electrification or
two kinds of electrical charge. At first these two
kinds were spoken of as vitreous or glass electricity
and resinous electricity, but after a while the idea
arose that there was really one kind of electricity and
that everything possessed a certain amount of it, the
electrified glass having a little too much of it and the
electrified resin a shade too little of it. From this
came the idea of calling the charge on the glass a
" positive " charge and that on the resin a " negative"
charge. Recent investigations seem to show that we
have got those two terms the wrong way round,
but to avoid confusion we still use them in the old
way.
It will be sufficient for our purpose, therefore, if we
assume that every molecule of matter has a certain
normal amount of electricity associated with it and
HOW PEACEFUL ARTS HELP IN WAR
that under those conditions the presence of the
electricity is not in any way noticeable. When a
molecule becomes ionized, however, one ion always
seems to run off with more than its fair share of the
electricity, the result being that one is electrified
positively, like rubbed glass, while the other is
negatively charged, like rubbed resin.
Thus, when the common salt is dissolved in water,
two lots of ions are formed, one lot positively charged
and the other lot negatively. Each molecule of salt
consists of two atoms, one of sodium and one of
chlorine : consequently, one ion is a chlorine atom
and the other is a sodium atom, the latter being
positive and the former negative.
Now the electrodes are also charged by the action
of the battery. That connected to the positive pole
of the battery becomes positively charged and the
other negatively. The anode, therefore, is positive
and the cathode negative.
It has been pointed out that two similarly charged
bodies, such as two pieces of glass or two pieces of
resin, repel each other, while either of these attracts
one of the other sort. Hence we arrive at a rule that
similarly charged bodies repel each other, while
dissimilarly charged bodies attract each other.
Acting upon this rule, therefore, the anode starts
drawing to itself all the negative ions, in this case the
atoms of chlorine, while the cathode gathers together
the positive ions, the atoms of sodium. Thus the
action of the battery maintains a sorting out process
by which the sodium is gathered together around one
of the electrodes and the chlorine round the other.
HOW PEACEFUL ARTS HELP IN WAR
Those ions, by the way, which travel towards the
an-ode are called an-ions, while those which go to
the cath-ode are termed cat-ions.
Thus far, I think, you will have followed me : the
chlorine is gathered to one place and the sodium to
the other. The former creates bubbles and floats up
to the surface and escapes. But where, you will ask,
does the hydrogen come from, which we found, in the
experiment, was bubbling up round the cathode.
Moreover, what becomes of the sodium ?
Both those questions can be answered together.
The sodium ions, having been drawn away from their
old partners the chlorine ions, are unhappy, and long
for fresh partners. They therefore proceed to join up
with molecules of water. But water contains too
much hydrogen for that. Every molecule of water
has two atoms of hydrogen linked up with one of
oxygen, but sodium does not like two atoms of
hydrogen : it insists on having one only. Accordingly
the oxygen atom from the water, together with one
of the hydrogen atoms, join forces with the sodium
atom into a molecule of a new substance, a most
valuable substance in many manufactures, called
Caustic Soda, while the odd atom of hydrogen,
deprived of its partners, has nothing left to do but to
cling for a while to the cathode and finally float up
and away.
The sum-total of the operation therefore is this :
when we pass an electric current through salt water,
between graphite electrodes, chlorine goes to the
anode and escapes, while caustic soda is formed
round the cathode and hydrogen escapes. Let us see
now how this is applied commercially.
22
HOW PEACEFUL ARTS HELP IN WAR
For the production of Chlorine the apparatus need
be little more than our experimental apparatus made
large. The anode can be covered in such a way as to
catch the gas as it bubbles upwards. In times of
peace this gas is chiefly used for making bleaching
powder. It is led into chambers where it comes into
contact with lime, with which it combines into
chloride of lime, a powder which is sometimes used as
a disinfectant, but the chief use of which is for
bleaching those cotton and woollen fabrics for the
manufacture of which this country is famous through-
out the world.
The Germans, however, have taught the world
another use for chlorine. Those gallant Canadians
who were the first victims of the attack by " poison
gas " who suddenly found themselves fighting for
breath, and a few of whom, more fortunate than the
rest, have reached their homes shattered in health
with permanent damage to their lungs, those brave
fellows suffered from poisoning by chlorine.
We cannot obtain the other product, the caustic
soda, by the same simple means. In our little
experiment we succeeded in manufacturing some of it
in the region around the cathode, and had we drawn
off some of the liquid from there we would have been
able to detect its presence. But it would have been
mixed up with much ordinary salt, and for com-
mercial purposes we need the caustic soda separate
from the salt. The principle is, however, just the
same, as you will see.
Imagine a large oblong vat divided by vertical
partitions into three separate chambers. These
23
HOW PEACEFUL ARTS HELP IN WAR
partitions do not quite reach the bottom of the vessel,
so that there is a means of communication between
all three chambers. This is closed, however, by
filling the lower part of the vat with mercury up to
a level a little higher than the lower ends of the
partitions.
Thus we have three separate chambers with
communication between them but that communica-
tion is sealed up by the mercury.
The two end chambers are filled with salt water,
or brine, while the centre one is filled with a solution
of caustic soda. In each end compartment is a stick
of graphite, both being electrically joined together
and so connected up that they form anodes, while in
the centre compartment is the cathode.
When the current flows from the anodes it carries
the sodium ions with it, just as it did in our little
experiment. But its course, this time, is not
straight, since in order to travel from anode to
cathode it has to pass through the openings in the
partitions, in other words through the mercury.
On arrival at or near the cathode the ions of sodium
cause the caustic soda to be formed just as in our
experiment, but in this case, you will notice, the
formation takes place in a chamber from which the
salt brine is completely excluded by the mercury.
Brine is continually fed into the outer chambers
and the solution of caustic soda is drawn from the
centre one, while the chlorine is collected over the
anodes.
And now we can go a step further on our progress
from common salt to explosive.
24
HOW PEACEFUL ARTS HELP IN WAR
In the soap works there are enormous coppers in
which are boiled various kinds of fat. The source of
the fat may be either animal or vegetable, many
kinds of beans, nuts and seeds furnishing fats practi-
cally identical with that which can be got from the
fat flesh of a sheep, for instance. To this fat is added
some caustic soda solution and the whole is kept
boiling for some considerable time. This protracted
boiling is to enable the soda thoroughly to attack the
fat and combine with it, whereby two entirely new
substances are formed.
At first the two new substances are not apparent,
for they remain together in one liquid. The addition,
however, of some brine causes the change to become
obvious for something in the liquid turns solid, so
that it can be easily taken away from the rest. That
solid is nothing else than soap. It remained dissolved
in the water which forms part of the liquid until the
salt was put in, but as it will not dissolve in salt water,
as you will discover if you attempt to wash in sea
water, it separates out as soon as the salt is added.
But still a liquid remains : what can that be ?
It is mainly salt water and glycerine, that sticky stuff
which in peace times we put on our hands if they get
sore in winter, or take, in a little water, to soothe a
sore throat. That it has other and very different
uses was brought home to me when, during the war,
I tried to buy some at a chemist's, only to learn that
it could not be sold except in cases of extreme need
under the orders of a doctor.
The mixed liquid is distilled with the result that
the water is driven off and the salt deposited, which
25
HOW PEACEFUL ARTS HELP IN WAR
with other minor purifying processes gives the pure
glycerine.
The next step takes us to the explosives factory,
where the glycerine is mixed with sulphuric and
nitric acids. Now glycerine, as you will have observed,
comes from the animal or vegetable sources and
therefore is one of those substances known as
" organic," and, like many other of the organic
compounds, it consists of carbon, hydrogen and
oxygen. Nature has a marvellous way of combining
these same three things together in many various ways
to form many widely different substances and if, to
such a compound, we can add a little nitrogen, we
usually get an explosive. Thus, the glycerine, with
some nitrogen from the nitric acid, becomes nitro-
glycerine, a most ferocious and excitable explosive,
the basis of several of those explosives without which
warfare as we know it to-day would be impossible.
26
CHAPTER II
GUNPOWDER AND ITS MODERN
EQUIVALENTS
THE origin of gunpowder appears to be lost in
antiquity. At all events it has been in
use for many centuries and is still made in
many countries.
Most boys have tried to make it at some time or
other and with varying degrees of success. Such
experiments generally lead to a glorious blaze, a
delightfully horrid smell and no harm to anyone, the
experimenter owing his safety to his invariable lack
of complete success, for although other and better
explosives have superseded it for many purposes it is
capable of doing a lot of harm when it is well made.
It consists of a mixture of charcoal, sulphur and
saltpetre ground up very fine and mixed very inti-
mately together. The mixture is wetted and pressed
into cakes and dried, after which it is broken up into
small pieces. The precise proportions of the various
materials seem to vary a great deal in different
countries, but generally speaking there is about
75 per cent of saltpetre (or to give it its scientific
name, nitrate of potash), 15 per cent of charcoal and
10 per cent of sulphur.
Now gunpowder, like all explosives, is simply
27
GUNPOWDER AND EQUIVALENTS
some thing or mixture of things which is capable of
burning very quickly. When we light the fire we set
going the process which we call combustion, or
burning, and, as we know from our own experience,
that process causes heat to be generated.
What takes place in the fire-grate is that the
carbon of the coal enters into combination with
oxygen from the air, the two together forming a new
compound called " carbonic acid gas." There is
nothing lost or destroyed in this process, the carbon
and oxygen simply changing into the new substance,
and could we weigh the gas produced we should find
that it agreed precisely with the weight of the carbon
and oxygen consumed. For the purpose for which
we require the fire, namely, to heat the room, the
chief feature about this process is not what is formed
in the shape of gas, for that simply goes off up the
chimney, but the heat which is liberated. We
believe that in some mysterious way the heat is
locked up in the coal. Latent is the term we use,
which means hidden : in other words we believe that
the heat is hidden in the coal : we cannot feel it or
perceive it in any way, but it comes out when we let
the carbon combine with the oxygen.
Why these two things combine at all is one of those
mysteries which may never be solved. We have
theories on the subject, but all we really know is that
under certain conditions if they be hi contact with
one another they will combine, apparently for the
simple reason that it is their nature so to do.
When we apply the match to the fire all we do is
to set up the conditions under which the carbon and
28
GUNPOWDER AND EQUIVALENTS
oxygen are able to follow their natural instincts, so
to speak.
A coal fire, as we all know, burns slowly, for the
simple reason that it is only at the surface of the
lumps that carbon and oxygen are in contact. If we
grind up the coal into a fine powder and then blow it
into a cloud, so that every tiny particle is surrounded
with air, a spark will cause an explosion. That is
how these terrible explosions hi coal-pits are caused.
This is sometimes seen on a small scale when one
shakes the empty fire-shovel after putting coal on the
fire to get rid of the fine dust adhering to it and to
save making a mess in the fender. That little cloud
of fine dust will often burst into flame like a mild
explosion.
We see from this that to make an explosion we
require fuel, just as we do to make a fire : but we
need that it shall be very intimately mixed with
oxygen, so that all of it can burn up in practically a
single instant. Now in gunpowder we get these
conditions fulfilled. We have the carbon in the shape
of charcoal, we also have some sulphur which likewise
burns readily, and we have saltpetre which contains
oxygen.
Thus, you see, we do not need to go to the air for
the oxygen, for the gunpowder possesses it already,
locked up in the saltpetre. Moreover, we can see now
why it is so important for all the materials to be
ground up very fine, for it is only by so doing that we
can ensure that every particle of charcoal or sulphur
shall have particles of saltpetre close by ready to
furnish oxygen at a moment's notice.
29
GUNPOWDER AND EQUIVALENTS
Another thing to be observed, for it lets us into the
great key to the manufacture of nearly all explosives,
is the scientific name of saltpetre. It is " nitrate of
potassium," and all substances whose names begin
with " nitr-" contain nitrogen : while the termina-
tion " ate " signifies the presence of oxygen. We
need the oxygen to make the explosion but we do not
need the nitrogen, yet the latter has to be present for
without it the oxygen would be too slow in getting to
work.
Nitrogen is one of the strangest substances on
earth. Extremely lazy itself, it has the knack of
hustling its companions, particularly oxygen, and
making them work with tremendous fury. When-
ever we get the lazy gas nitrogen to enter into a
combination with other things we may confidently
look for extraordinary activity of some sort.
So when we put a light to a quantity of gun-
powder we set up those conditions under which the
carbon and oxygen can combine, and at the same
moment our lazy friend the nitrogen turns out his
partner oxygen from the nitrate in which they were
till then combined and a sudden burning is the
result. The solid gunpowder is suddenly changed
into a volume of hot gas 2500 times as great. That is
to say, one cubic inch of gunpowder changes suddenly
into 2500 cubic inches of gas. That sudden expan-
sion to 2500 times its volume is what we term an
explosion. If it takes place in an enclosed space so
that the gas formed wants to expand but cannot, the
result is a pressure of about forty tons per square
inch.
GUNPOWDER AND EQUIVALENTS
If that enclosed space were the interior of a gun,
that force of forty tons per square inch would be
available for driving out the projectile.
Now, gunpowder is still used for sporting purposes
and also for some special purposes in warfare, but it
has the great disadvantage that it makes a lot of
smoke, so that the enemy would be easily able to
locate the guns were it to be used in them. As we
know so well, by the messages from France, guns and
rifles drop their shells and bullets apparently from
nowhere and are extremely difficult to locate. That
is owing to the use of improved powders one of the
great features of which is their smokelessness.
The reason why gunpowder makes a dense smoke,
is because the burning which takes place is very
incomplete. Therefore, by some such means as a
more intimate mixture of the materials a better
and more complete burning must be brought about.
One of the best known of the new powders (they
are all spoken of as powders, whatever their form,
since they have taken the place of the old gun-
powder) is nitro-glycerine, the basis of which is
glycerine.
The way in which we obtain this useful material
has already been explained. It consists of carbon, a
lot of hydrogen and some oxygen. These are not
merely mixed together but are in combination, just as
oxygen and hydrogen are combined in water. Carbon
and hydrogen will both combine with oxygen and
will give off heat in the process, but in glycerine they
are already happily united together and so glycerine
itself is no use as an explosive. If, however, we bring
GUNPOWDER AND EQUIVALENTS
nitric acid and sulphuric acid into contact with it a
pair of new partnerships is set up, one being water
and the other a compound containing carbon and
hydrogen, a lot of oxygen and, most important of all,
some of that disturbing, restless though lazy nitrogen.
This is nitro-glycerine, a particularly furious explo-
sive, for that curious nitrogen seems to be so un-
comfortable in his new surroundings that at the
smallest provocation he will break up the whole
combination and then there will be a mass of free
atoms of carbon, hydrogen and oxygen, all seeking
new partners, just right for a glorious explosion.
So furious and untamed is this stuff that it was
almost useless until the famous Nobel hit upon the
idea of taming it down by mixing it with an earth
called Kieselguhr, which reduces its sensitiveness
sufficiently to make it a very safe explosive to use.
To this mixture Nobel gave the name of dynamite.
It is interesting at this point to compare the action
of this typical modern explosive with that of the
older gunpowder. The latter is only a mixture : the
former is a chemical compound. The smallest
particle of material in the gunpowder is a little lump
containing millions of molecules and still more of
atoms : when the nitrogen has broken up the original
nitro-glycerine, just before the explosion actually
takes place, we have a mixture of single atoms. Thus
the mixture is far more intimate in the latter case and
the burning is therefore quicker and more thorough.
Another well-known explosive is gun-cotton. Surely
this must be a fancy name, for what can harmless,
simple cotton have to do in connection with guns.
32
TKTS-^V'.,:
This illustrates the
MACHINE-GUN versus RIFLE.
pidity and accuracy with which the modern rifle can be used.
of five and killed t
to the " Brown Bess" of a hundred years ago.
Sergeant O'Leary, V.C., tackled a gun crew of five and killed them all before they had time
to slew their gun round a striking contrast
GUNPOWDER AND EQUIVALENTS
It is a perfectly genuine descriptive name, however.
It seems very strange at first, but it is perfectly true
that nitrogen, as it turned glycerine into dynamite,
can also turn cotton into gun-cotton. Cotton consists
mainly of cellulose, a compound of carbon, hydrogen
and oxygen, happily combined together and there-
fore showing, as we well know from experience, no
tendency whatever to change into anything else,
least of all to " go off bang." But that state of things
is very much changed when we have induced nitrogen
to take a hand in the game.
In actual practice, cotton waste, pure and clean, is
dipped into a mixture of sulphuric and nitric acids
whereby the cellulose becomes changed into nitro-
cellulose, just as a similar process changes glycerine
into nitro-glycerine. The whole process of manu-
facture is of course far more than that simple dipping,
but that is the fundamental fact of it all. The rest
is concerned with getting rid of the superfluous acid,
tearing the stuff into pulp and pressing it into blocks.
It is probably the safest of explosives, since it can be
kept wet, in which case the danger of an accidental
explosion is practically nil, provided reasonable care
be taken. Even when dry, it behaves in a very
kindly way. If hit with a hammer, it only burns for
a moment just at the point struck. If ignited with a
red-hot rod, it burns but does not explode, unless it is
enclosed. The burning, that is to say, is not suffi-
ciently rapid to constitute an explosion.
On the other hand, if it be exploded by a detonator,
by which is meant a small quantity of a very power-
ful explosive, such as fulminate of mercury, fired close
c 33
GUNPOWDER AND EQUIVALENTS
to it, it then goes off with a violence which leaves
little to be desired.
It would be better still could we persuade a little
more oxygen to enter into its composition, for as it is
there is not quite enough to burn up the other
matters completely. That, however, does not cause
smoke, since the combustion is complete enough to
change everything into invisible gases. With more
oxygen more heat might be generated and the power
of the explosion be made greater. Still, even as it is,
the explosion of gun-cotton has been estimated by a
high authority to produce a pressure of 160 tons
per square inch, four times as much as gunpowder.
Nitro-glycerine has the advantage of a rather larger
proportion of oxygen to carbon, resulting in its being
rather more energetic.
Yet another class of explosive is made from Coal
Tar. This is a by-product in the manufacture of
gas for lighting and also in the manufacture of coke
for industrial purposes. It comes from the retorts
along with the gas in a gaseous form but condenses
into a black liquid in the pipes and more particularly
in an arrangement of cooled pipes called a condenser
specially placed to intercept it.
In the chemist's eyes it is the most interesting of
liquids, for it is full of mysteries and possibilities.
The most wonderful achievements of chemistry have
it for their raw material and there is still scope for
much more in the same direction.
If the tar be gently heated in a closed vessel it will
evaporate and the vapour can be led to another vessel,
there cooled and converted back into a liquid. This
34
GUNPOWDER AND EQUIVALENTS
looks rather like doing work for nothing, but the
various liquids, of which tar is a mixture, evaporate
at different temperatures, so that this furnishes a
means of separating them. The first liquid thus
procured is known as coal tar naphtha, and if it be
again distilled it can be subdivided further, the first
liquid separated from it being known as Benzine.
This, again, is another of those almost numberless
things which consist of carbon and hydrogen. Also,
like the other similar substances which we have been
discussing, it can, if treated with nitric acid, be made
to take into partnership a quantity of oxygen and
nitrogen.
Thus we get nitro-benzene. We can repeat the
process, when it will take more and become di-nitro-
benzene. Again we can repeat it, thus producing
tri-nitro-benzene.
The second liquid separated from coal tar naphtha
is called Toluene, which again is composed of carbon
and hydrogen in slightly different proportions. Like
its confrere benzene it, too, can be treated with
nitric acid, becoming nitro-toluene and then di-
nitro-toluene and finally tri-nitro-toluene, the deadly
explosive of which we read in the papers as T.N.T.
After the naphtha has been removed from the tar
another substance is obtained called Phenol, which
in a prepared form is familiar to us all as the dis-
infectant Carbolic Acid. It also can be treated with
nitric acid, to produce tri-nitro-phenol, otherwise
known as Picric Acid, which after a little further
treatment becomes the famous " Lyddite."
Most of the actual explosives used in warfare are
35
GUNPOWDER AND EQUIVALENTS
prepared from one or more of the above-mentioned
compounds. For example, nitro-glycerine and gun-
cotton, having been dissolved in acetone (another
compound of carbon, hydrogen and oxygen) and a
little vaseline added, form a soft gelatinous substance
which on being squeezed through a fine hole comes
out looking like a cord or string, and hence is called
Cordite.
Other explosives are finished in the form of sheets,
the dissolved gun-cotton or whatever it may be
being rolled between hot rollers which give it the
convenient form of sheets and at the same time
evaporate the solvent.
By combining these various substances various
characteristics can be given to the finished explosive.
For instance, the one which drives the shell from the
gun, known as the propellant, must not be too
sudden in its action. It must push steadily. Its
purpose is to drive the shell not to burst the gun,
wherefore its action must be comparatively slow and
continuous so long as the shell is still in the gun.
It must " follow through " as the golf player would
put it.
The charge in the shell, however, needs to go off
with the greatest possible violence so as to blow the
shell to pieces and to scatter the fragments so that
they do the maximum of damage.
Those explosives, whose function is thus to burst
with a sudden shock, are called High Explosives, as
distinguished from the propellants which produce a
more or less sustained push.
The great fundamental principle which enables
36
GUNPOWDER AND EQUIVALENTS
large quantities of these powerfully explosive sub-
stances to be handled with comparative safety
involves the use of two different substances in com-
bination. That which is used in quantity and
which actually does the work is made comparatively
insensitive, indeed in some cases it is very insensitive,
so that it can safely travel by train, by ship and by
road and also may be handled by the soldiers and
sailors with very little risk. Some of these compounds
can be struck or set on fire with impunity. They are
none the less violent, however, when, by the agency
of a suitable detonator they are caused to explode.
The detonator, of course, has to be very sensitive
indeed, but it need only be used in very small
quantities, so that by itself it, too, is comparatively
safe. Fulminate of mercury is often employed for
this purpose a compound based upon mercury but
in which nitrogen of course figures largely.
Thus, there are two things necessary for the
successful explosion, one of which is powerful but
insensitive, while the other is highly sensitive but
relatively harmless since it is never allowed to exist
in large quantities, and as far as possible these are
kept apart until the last moment.
One other thing may be mentioned in regard to this
matter which is of the greatest importance. That is
the necessity for the utmost uniformity in these
various compounds, so that when the gunners put a
charge into a gun they can rely upon it to throw the
shell exactly as its predecessor did. Modern artillery
seeks to throw shell after shell within a small area
which would clearly be quite impossible if one charge
37
GUNPOWDER AND EQUIVALENTS
were liable to be stronger or weaker than another, for
we can easily see that the more powerful the impetus
given the farther will the shell go.
To secure this uniformity the greatest care is taken
at all stages of the manufacture, and various batches
of the same stuff are tested and mixed, and any of
them turning out a little too strong are placed with
some a little too weak, so that their faults may
neutralize each other. By such methods as these a
remarkable degree of uniformity is attained, the
result of which we see when we read in the papers of
the wonderfully accurate gunnery of which our
soldiers and sailors are capable.
In conclusion, a word of warning may be appro-
priate. Reference has been made above to the safety
of modern explosives in the absence of the detonators,
but do not let that lead anyone to take liberties.
Should any reader come into possession of any of
these materials, even in the smallest quantities, let him
treat it with the utmost respect, for although what
has been said about safety is quite correct, it only
means comparative safety, there can be no absolute
safety where these substances are concerned.
CHAPTER III
RADIUM IN WAR
WHEN we remember how all forms of
scientific knowledge were called upon
to help in the great struggle, it is not
surprising to hear that, although in a comparatively
humble way, Radium has had to do its share.
Now radium is one of the most, if not actually the
most, remarkable substance known. About a genera-
tion ago scientific men, or some of them at all events,
were getting rather cocksure. Of course they were
quite right when they realized how much was known
about things and what great strides had been made
during the years through which they had lived.
They were proud of the achievements of their scien-
tific friends, for I am not imputing personal vanity to
anyone, and they had reason to be proud. They
made the mistake, however, of thinking that in one
direction at least they had learnt all that there was
to be known. The present generation of scientific
men seem to be almost too prone to go to the other
extreme and to dwell rather much on how little we
know now and the wonderful things which are going
to be discovered in time.
But that is by the way. A generation ago men
seem to have pretty well made up their minds that
39
RADIUM IN WAR
they knew all about atoms. They said that every-
thing was made up of atoms, that the atoms could
not be subdivided nor changed into anything else
except temporarily by combination with other atoms,
and that when these combinations were broken up
the atoms remained just as before, quite unchanged.
They believed that the atoms were unchangeable and
everlasting. Professor Tyndall, in a famous address,
referred to this in somewhat flowery language, telling
his hearers that the atoms would be still the same
when they and he had " melted into the infinite azure
of the past," which a wag translated into the slang
expression of the time, " till all is blue."
Now not very long after Professor Tyndall made
this historic speech Professor Henri Becquerel, of
Paris, was trying some experiments with phos-
phorescent materials, that is, materials which glow
in the darkness. In the course of these experiments
he used some photographic plates upon which, to his
surprise, he found marks which he thought ought not
to have been there. Thinking at first that he had
accidentally " fogged " his plates, as every photo-
grapher has done at some time or other, he tried his
experiments again with special care but still he got
the mysterious marks.
Those marks were caused by some of those " un-
changeable and everlasting " atoms deliberately and
of their own accord blowing themselves to bits.
For the celebrated Frenchman was not content to
let the matter of those mysterious marks rest : he
wanted to know what caused them and he did not
desist until he was on the track of the secret. It
40
RADIUM IN WAR
appeared after careful investigation that they were
made by the action of something in some of the ore
of the metal " uranium " which he had been using.
Moreover, this something evidently had the power
of penetrating through the walls of the dark-slide to
the plate within. Finally, it was tracked down to the
uranium itself which was unquestionably proved to
be giving off something in the nature of invisible
light, or at all events invisible rays, of strange pene-
trative power. A little later it was observed that
certain ores of uranium seemed to give off these rays
more freely than would be accounted for by the
amount of uranium present, from which fact it was
inferred that there must be something else present
in the ore capable of giving off the rays much more
powerfully than uranium can. Madame Curie ulti-
mately found out two such substances, one of which
she called, after her native land, Polonium (for she is
a Pole), and the other Radium. It is the latter which
is responsible for by far the greater part of the rays
formed.
The rays are invisible, but they affect a photo-
graphic plate in the same way that light does. They
also make air into a conductor of electricity and if
allowed to impinge upon a surface coated with a suit-
able substance they cause it to glow.
This spontaneous giving off of rays is now spoken
of by the general term of " radio-activity," and it
has grown into an important branch of science. A
number of other substances have been found to ex-
hibit the same peculiar ray-forming powers, notably
Thorium, one of the components of the incandescent
RADIUM IN WAR
gas mantle by the prolonged application of a fragment
of which to a photographic plate an impression can
be obtained due to the rays.
What, then, are these rays ? It is found that they
are of three kinds, not that they vary from time to
time, but that they can be sorted out into three
different sorts of rays which are given off simul-
taneously all the time.
The first sort are stopped by a sheet of paper, the
second passing easily through a thick metal plate,
while the third appear to be identical with X-rays.
For convenience the three sorts are termed Alpha,
Beta and Gamma rays, respectively, after the first
three letters of the Greek alphabet.
Further, the Alpha rays prove to be a torrent of
tiny particles about the size of atoms, indeed if they
be collected the gas Helium is obtained, so that
evidently they are helium atoms, and since that is
one of those substances whose molecules consist of a
single atom each they are also molecules of helium.
No doubt the reason why they are so easily stopped
by a piece of paper is because being complete atoms
they are large, huge indeed, compared with the
particles which form the Beta rays, for they are
apparently those same electrons which are found in
the X-ray tube, and which are at least 2000 times
smaller than the smallest atom.
When the electrons in the vacuum tube are sud-
denly brought to a standstill X-rays are given off and
in like manner X-rays no doubt would be given off
when they start on their journey, providing that they
started suddenly enough. Hence it is the starting
42
RADIUM IN WAR
or sudden explosion-like ejection of the Beta particles
which is believed to give rise to the Gamma
rays.
The strength or intensity of the rays can be
measured very conveniently by their action in making
air conductive to electricity, for which purpose a very
beautiful but simple instrument called an Electro-
scope is employed. It consists generally of a glass-
sided box or else a bottle with a large stopper,
consisting of sulphur or some other particularly good
insulator. Through this a wire passes down into the
inside of the vessel terminating in a vertical flat strip
to the upper end of which is attached a similar strip
of gold leaf or aluminium foil. Normally the leaf
hangs down close to the strip, but if the wire above
the stopper be electrified by touching it with a piece
of sealing-wax rubbed lightly against the coat sleeve
the charge of electricity passes down into the inside
and causes both strip and leaf to become so electrified
that they repel each other.
Owing to the non-conductivity of the air in its
normal condition the leaf will, if the insulation of the
stopper be good, remain projecting almost hori-
zontally for some time until, as it loses its charge
by a slow leakage, it gradually settles down close to
the strip.
If, however, a piece of radium be brought near
while it is sticking out, the leaf will fall almost
instantly. X-rays have a similar effect even from
several feet or yards away.
The intensity of the radio-activity of different
substances can be compared by noting the difference
43
RADIUM IN WAR
in the rate at which the leaf falls under the influence
of each.
What is happening, then, to the atoms of radium,
which causes them to show these curious effects and
to give off these strange rays ? To give any intelli-
gent answer to that question we are bound to assume
that which the older generation of scientists thought
impossible, namely, that atoms can be broken up.
Then we are forced to believe that the atoms of this
particular substance radium are of a peculiarly flimsy
unstable sort, so that they cannot permanently hold
their parts together but are liable to break up, as far
as we can see through their own inherent weakness
and under the influence of disruptive forces at work
within themselves.
We must remember, however, that the tiniest
speck of matter which we can see contains a number
of atoms of such a size as to be quite beyond the
grasp of our minds. To give a rough idea of it in
figures is useless as no one can comprehend the real
value of a figure or two followed by probably from
a dozen to twenty " noughts." It is best to content
ourselves with the general statement that a speck
of matter only just visible to the eye contains an
exceedingly vast number of atoms. Of course a
speck of radium is no exception to this and we must
remember, too, that all of them do not break up at
once. Indeed, the number breaking up at any time
are actually countable by means of a very simple
contrivance and a sensitive electrometer. Conse-
quently, in view of the enormous number present
and the comparatively small number breaking up
44
RADIUM IN WAR
at any moment, it is not surprising to hear that, so
it is estimated, the process can go on for an almost
indefinite number of years, certainly for hundreds.
There are, moreover, certain facts which we need not
go into here from which the above fact can be clearly
inferred, quite apart from what has been said about
the vast numbers of the atoms.
It seems as if the uranium atoms break up first,
giving off helium atoms and electrons and leaving
an intermediate substance called Ionium which in its
turn breaks up giving off the same things again and
leaving radium. That in its turn goes through a com-
plicated series of changes still giving off the same
alpha particles or atoms of helium and electrons
until, it is suggested, it finally settles down into the
simple commonplace metal lead of which we make
bullets and water pipes and such-like ordinary things.
We see then that all through its history its radio-
active history at any rate this stuff is throwing off
atoms of helium at a very high velocity (about
50,000 miles a second), and if it be enclosed in any-
thing this enclosing vessel or substance will be sub-
jected to a continual bombardment by the alpha
particles. Now just as a piece of iron gets hot if we
hammer it, so the enclosing matter is heated by the
continual blows which it is receiving night and day,
year in and year out, from the alpha particles.
Consequently the immediate surroundings of a
speck of radium are always slightly raised in tem-
perature.
Moreover, if a speck of radium be placed against
a screen covered with suitable materials each particle
45
RADIUM IN WAR
which strikes it will make a little splash of light. At
least that is what it looks like when seen through a
magnifying glass, but to the naked eye there only
appears a beautiful steady glow.
Suppose, then, that instead of putting the speck
of radiant matter in front of a screen we mix it up
intimately with a fluorescent substance such as sul-
phide of zinc, we then get the same conditions in a
slightly different form. Each particle of the substance
serves as a tiny screen which glows every time a
particle hits it. Thus is produced a luminous paint
which glows by night, suitable for painting the dials
of instruments which have to be used in the dark.
No doubt some of my readers will have experienced
the strangely mingled delight and horror of seeing
a Zeppelin in the night sky intent on dropping
murder and death on the sleeping civilians of a
peaceful town or city. Some too may have wit-
nessed the later acts in that wonderful drama, when,
beside the silvery monster illuminated by the beams
of the searchlight there must have been, though quite
invisible, a little aeroplane manned by one man or
at most two. That aeroplane was, no doubt, fitted
with instruments at which the pilot glanced now and
then and which he was able to see and read
because of the tiny speck of radium mixed into
the paint. The little alpha particles gave him
the light by which to see, but they gave no
help to the Germans on the Zeppelin. Hence, in
due time he did his work and the gigantic balloon,
the pride of the Kaiser and his hordes, fell to the
ground, a blazing wreck. How he did it I cannot
46
RADIUM IN WAR
tell, but of this I am sure, that most probably radium
helped him by making luminous and visible the
instruments which guided him.
But probably it has rendered and will still render
us even greater services in the way of helping to
repair the damages to our injured manhood. How
many men came back from the war crippled with
rheumatism because of the hardships through which
they went. That disease is believed to be due to a
substance which mingles with the blood and which,
although usually liquid and harmless sometimes
changes into a solid and settles in the joints. Now
it is believed that radium properly administered will
act upon that solid and cause it to change back into
its liquid form again, thereby curing the disease.
Certainly many of the mineral springs at such places
as Bath and Buxton give forth a water which shows a
certain amount of radio-activity and it may be that
which gives those waters their healing properties.
If so, we may look forward with confidence to the
time when radio-activity will be induced to play a
still more successful part in meeting this painful and
widespread illness.
Then, of the other ills which will inevitably arise
in our men through the hardships which they have
endured are sure to be some of the cancerous type,
many of which appear to succumb to treatment by
radium. If a very small quantity indeed be carried
for a few days in a pocket it will imprint itself upon
the skin beneath as if it burnt the tissues. It is never
advisable, therefore, to carry radium in the pocket
without special precautions. One cannot help
47
RADIUM IN WAR
feeling, however, that in that little fact is a hint of
usefulness when the best modes of application have
been discovered, for as a means of safely and pain-
lessly burning away some undesirable growth it
would seem to be without a rival. It is said, too,
that it has the strange power of discriminating
between the normal and the abnormal, attacking the
latter but leaving the former, so that when applied,
say, to some abnormal growth like cancer it may be
able to remove it without harmful effect upon the
surrounding tissues.
Of this, however, it is too soon to write with
confidence. It has not been known long enough for
our doctors to find out the best modes of use, but
that will come with time : meanwhile there are
indications that in all probability it will render good
service to mankind.
CHAPTER IV
A GOOD SERVANT, THOUGH A
BAD MASTER
ONE morning during the war the whole
British nation was startled to learn that
Mr. Lloyd George, then the Minister of
Munitions, had taken over a large number of dis-
tilleries. Could it be that he, a teetotaller and tem-
perance advocate, was going to supply all his workers
with whiskey ? Or was he going to close the places
so as to stop the supply of that tempting drink ?
Neither of these suggestions was his real reason.
What he wanted the distilleries for was to make
alcohol for the war, not for drinking purposes but
for the very many uses which only alcohol can fulfil
in most important manufactures.
Probably alcohol is the next important liquid to
water. For example, certain parts of shells have to
be varnished and the only satisfactory way to make
varnish is to dissolve certain gums in alcohol. The
spirit makes the solid gum for the time being into a
liquid which we can spread with a brush, yet, after
being spread, it evaporates and passes off into the
air, leaving behind a beautiful coating of gum. That
is how all varnishing is done, the alcohol forming
the vehicle in which the solid gum is for the moment
D 49
A GOOD SERVANT
carried and by which it is applied. It is far and
away the most suitable liquid for the purpose, and
without it varnishing would be very difficult and un-
satisfactory. Hence one need for alcohol, to carry
on the war.
Then again some of the most important explosives
are solid or semi-solid, and yet they require to be
mixed in order to form the various " powders " in
use by our gunners. The best way to bring about
this mixture is to dissolve the two components in
alcohol, thereby forming them both into liquids which
can be readily mixed. Afterwards the alcohol
evaporates ; indeed, one of its great virtues for this
and similar purposes is that it quietly takes itself
off when it has done its work like a very well-drilled
servant.
What then is this precious liquid and how is it
produced ? In order to answer that question it is
necessary first to state that there are a whole family
of substances called " alcohols," all of which are
composed of carbon, hydrogen and oxygen in certain
proportions. There are also a number of kindred
substances also, not exactly brothers but first cousins,
so to speak, which because of their resemblance to
this important family have names terminating in
"ol."
They owe their existence to the wonderful be-
haviour of the atoms of carbon. In order to obtain
some sort of system whereby the various combina-
tions of carbon can be simply explained chemists
picture each carbon atom as being armed with four
little links or hooks with which it is able to grapple, as
50
A GOOD SERVANT
it were, and hold on to other atoms. Each hydrogen
atom, likewise, has its hook, but only one instead of
four.
Now it is easy to picture to ourselves an atom of
carbon in the middle with its hooks pointing out
north, south, east and west with a hydrogen atom
linked on to each. That gives us a picture of the
molecule of Methane, the gas which forms the chief
constituent of coal gas such as we burn in our homes.
Methane is also given off by petroleum and it is the
cause of the explosions in coal mines, being known to
the miners as " firedamp." It is the first of a long
series of substances which the chemist called paraffins.
The first, as you see, consists of one of carbon and four
of hydrogen. Add another of carbon and two more
of hydrogen and you get the second " Ethane." Add
the same again and you get the third, Propane, and
so on until you can reach a substance consisting of
thirty-five parts of carbon and seventy-two parts of
hydrogen. All we need trouble about, however, is
the first two, Methane and Ethane.
We have pictured to ourselves the molecule of
methane : let us do the same with ethane. Imagine
two carbon atoms side by side linked together or
hand in hand. Each will be using one of its hooks to
grasp one hook of its brother atom. Hence each will
have three hooks to spare on to which we can hook a
hydrogen atom. Thus we get two of carbon and six
of hydrogen neatly and prettily linked up together.
The atoms form an interesting little pattern and to
build up the various paraffin molecules with a pencil
and paper has all the attractions of a puzzle or game.
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A GOOD SERVANT
All you have to do is to add a fresh atom of carbon
alongside the others and then attach an atom of
hydrogen to each available unused hook. If you
care to try this you will get the whole series, each one
having one atom of carbon and two of hydrogen more
than its predecessor.
If you mix together a quantity of methane and an
equal quantity of chlorine, which I have shown you
in another chapter how to get from common salt, a
change takes place, for in each molecule of methane
one hydrogen atom becomes detached and an atom
of chlorine takes its place. How or why this change
occurs we do not know. It is a fact that the
chlorine has this power to oust the hydrogen and
there we must leave it, for the present at any
rate. The substance so formed is called methyl
chloride.
In another chapter reference has been made to
that substance which is made from common salt
and which is so important in so many manufactures
called caustic soda. If we bring some of it into
contact with the methyl chloride the chlorine is
punished for its rudeness in displacing the hydrogen ;
it is paid back in its own coin, for it is in turn dis-
placed not this time by a single atom but by a little
partnership called " hydroxyl " one atom of hydrogen
and one of oxygen acting together. We can again
form a neat little picture of what happens. The
oxygen atom has two hooks, one of which it gives to
its friend the hydrogen atom and thus they go about
hand-in-hand, the oxygen having one unused hook
with which to hook on to something else. In this
52
A GOOD SERVANT
case it hooks on to that particular hook from which
it pushes the chlorine.
We have thus seen two changes take place. First,
the hydrogen is displaced by the chlorine : then the
chlorine is turned out and its place taken by the
hydroxyl. And during both these changes the
central carbon atom and its three hydrogen partners
have remained unaffected. Those four atoms are
called the methyl group, and a methyl group com-
bined with a hydroxyl group forms methyl alcohol.
Similar changes can be brought about with Ethane
as with Methane, and in them the two carbon atoms
and the five hydrogen remain unchanged, whence they
too are regarded as a group, the Ethyl group, and an
ethyl group hooked on to a hydroxyl group gives us a
molecule of ethyl alcohol.
These groups of which we have been speaking
never exist separately except at the moment of
change, but in the wonderful changes which the
chemist is able to bring about the atoms forming
these groups seem to have a fondness for keeping
together and moving together from one substance
into another. In a word, they behave as if they were
each a single atom and they are called by the name of
Radicles ; the word simply means a little root.
The methyl radicle and the ethyl radicle, since
they form the basis of two of the paraffin series, are
called paraffin radicles, so that we can describe this
useful alcohol as a paraffin radicle with a hydroxyl
radicle hooked on to it. If we use the methyl radicle
we get methyl alcohol : if we use the ethyl radicle
we get ethyl alcohol.
53
A GOOD SERVANT
Now ethyl alcohol is the spirit which is contained
in all strong drink. Whiskey has as much as 40 per
cent and brandy and rum about the same, while ale
has only about 6 per cent. All of them may be
regarded as impure forms of ethyl alcohol, the
various impurities giving to each its particular taste.
Ethyl alcohol, too, is what is sold at chemists'
shops as " spirits of wine," where also we can pur-
chase that which is familiar as " methylated spirits,"
whereby there hangs a tale.
All Governments regard alcohol for drinking as a
fit subject for taxation. When anyone buys a drink
with alcohol in it a part of what he pays goes to the
Government in the form of duty. On the other hand,
when alcohol is used for trade purposes, for making
varnish or something like that, there is no reason
whatever why it should be charged with duty. But
if the varnish manufacturer is to have alcohol duty-
free what is to prevent him from using some of it for
drinking ?
To get over the difficulty, that which is supplied to
him or to anyone else for trade purposes is deliberately
adulterated so as to make it so extremely nasty that
no one is likely to want to put it in his mouth.
It so happens that methyl alcohol, while as good
as the other for many purposes, is horrible to the
taste and so it forms a very convenient adulterant
for this purpose. Therefore, when methylated
spirit is sold to you for drying your photographs,
the chemist gives you ethyl alcohol with enough
methyl alcohol in it to make sure that neither you
nor anyone else will ever want to drink it.
54
A GOOD SERVANT
That, then, is alcohol : a near relative of paraffin
oil and also of coal gas, yet it is from neither of these
that we get it. The changes described above enable
you to realize what it is, but they do not tell how it is
made in large quantities.
Ethyl alcohol is obtained from sugar by the employ-
ment of germs or microbes. Any sort of sugar will
do : it need not be sugar such as we eat. In practice
the sugar is usually obtained from starch, that very
common substance which forms the material of
potatoes, grain of all kinds, beans and so on. There
is a kindly little germ which will quite readily turn
starch into sugar for us if we give it the chance.
The maltster starts the process. He gets some
grain, and spreading it out in a damp condition upon
his floor sets it a-growing. As soon as it has just
started to grow, however, he transfers it to his kiln,
where by heating it he kills the young plants. As is
well known, every seed contains the food to nourish
the little growing plant until it is strong enough to
draw its supplies from the soil and the food thus
provided for the young wheat plant is starch, which,
when it is ready for it, it turns into sugar. The little
shoot lives on sugar and the maltster and distiller
conspire to steal that sugar intended for the baby
plants and turn it into alcohol.
So the little plant liberates by some wonderful
means a material called diastase, which has the power
of changing starch into sugar. It does it, of course, for
the purpose of providing its own necessary food, but
the maltster does not want the process to go too far :
he only wants to produce the diastase, and that is
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A GOOD SERVANT
why he kills the plants, after which he has finished
with the matter and hands the " malted " grain or
" malt " over to the distiller for the next process.
The distiller mixes the malt with warm water,
whereupon the diastase commences the conversion of
the starch of the grain. At this stage fresh grain
may be added and potatoes, indeed almost anything
composed largely of starch for the diastase to work
upon. The process goes on until, in time, the liquid
consists very largely of sugar dissolved in water,
which is strained away from what is left of the
grain, etc.
Malt sugar is very similar to, but not quite the
same as, cane sugar. It consists of twelve parts of
carbon, twenty-two of hydrogen and eleven of
oxygen. It is an interesting little puzzle to sketch
those atoms out on paper, each with its proper
number of hooks, and see how they can be combined
together. Malt sugar, milk sugar and cane sugar all
consist of the same three elements in the same
proportions and the difference between them is no
doubt due to the different ways in which the atoms
can be hooked up together.
Yeast is next added to the liquid, upon which the
process of fermentation is set up, the tiny living cells
of the yeast plant producing a substance which is
able to change the sugar into alcohol.
The alcohol thus formed is, of course, combined
with water, but it can be separated from it by gentle
heating since it passes off into vapour at a lower
temperature than does water. Thus the vapour
first arising from the mixture is caught and cooled
56
A GOOD SERVANT
whereby the liquid alcohol is obtained. This opera-
tion, called fractional distillation, has to be repeated
if alcohol quite free from water is required, in
addition to which the attraction which quicklime
has for water is called into play to coax the last
remnant of water from the other.
And now, how about the methyl alcohol ? That is
obtained in quite a different way, by heating wood
and collecting the vapours given off by it. Hence
it is often called " wood spirit."
As a matter of fact, at least two very valuable
substances are obtained by this operation, methyl
alcohol and acetone.
The vapours given off by the wood are cooled,
whereupon tar is formed while upon it there floats a
dark liquid which contains the wood spirit, acetic
acid and acetone.
To capture the acetic acid lime is added to the mix-
ture, and since there is a natural affinity between them,
the acetic acid and lime combine into a solid which
remains behind when the whole mass is suitably
heated. What comes over in the form of vapour is a
mixture of water, acetone and wood spirit. The
former is enticed away by the use of quicklime, while
the other two are separated by the process of
fractional distillation already referred to.
Now let me ask you to form another little picture,
either in your mind or with paper and pencil.
Imagine two methyl radicles, each, let me remind you,
a carbon atom with three hydrogen atoms hooked on
and one spare hook. Also imagine one atom of
oxygen with its two hooks outstretched like two arms,
57
A GOOD SERVANT
and just link one radicle on to each. Then you have
the picture of methyl ether. All the ethers are
formed by taking two of the paraffin radicles and
linking them together by means of the two hooks of
an oxygen atom. The ether which is so largely used
in hospitals for wounded soldiers is ethyl ether,
consisting of two ethyl radicles joined by oxygen.
How it is made we will come to in a moment, but as
you see already it is a close relative of alcohol.
Now from methyl ether take away the central
oxygen and in its place put carbon. This atom will
have two hooks to spare which it can employ to
hold on to the two hooks of the oxygen. The result is
a molecule of acetone.
This is used as a solvent in a similar manner to
alcohol for many purposes, and there was a great
demand for it no doubt during the war.
One interesting use of acetone is in connection with
the gas acetylene. Of great use both for lighting and
also in conjunction with oxygen for welding and
cutting metals, this gas suffers from the disadvantage
that it cannot be compressed into cylinders and
carried about as oxygen can. It can, however, be
dissolved in acetone. The cylinders in which it is
carried are therefore filled with coke saturated with
acetone and then when the acetylene is pressed in it
dissolves, coming out of solution again as soon as the
pressure is released. In this dissolved condition it is
quite safe to carry about.
For a moment let us turn back to the commence-
ment of the chapter to the subject of methane.
When mixed with chlorine, it will be remembered, one
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A GOOD SERVANT
hydrogen atom gave place to a chlorine atom. If
the process be repeated another hydrogen atom will
be displaced in the same way, while a further
repetition will result in the removal of a third, when
there will be a carbon atom in the centre with three
chlorine and one hydrogen hooked on to it. With
that picture in your mind's eye you will be con-
templating the molecule of that wonderful and
beneficent substance, chloroform. When we think
of the numberless operations which have been carried
out by the surgeons in the course of this last war we
realize a little how great is the total sum of pain and
suffering which has been saved through the agency
of this substance, this simple neat little arrangement
of five tiny atoms.
Now that again is obtained in manufacture from
alcohol. Alcohol, bleaching powder and water are
mixed and then distilled, by which of course is
meant that the mixture is evaporated by heat and
the vapour collected and cooled back into liquid
again. The liquid so obtained is chloroform.
Hardly less important than this, in our military
hospitals, is ether, to which reference has already
been made. It, too, is manufactured from alcohol.
The alcohol, together with sulphuric acid, is placed in
a still and heated, the vapour given off being led to
another vessel and there condensed. The liquid thus
obtained is ether and so long as the supply of fresh
alcohol is kept up the production of ether goes on
continuously.
The sulphuric acid does not disappear and so does
not need to be replaced, from which it would appear
59
A GOOD SERVANT
as if it might just as well not be there, but that is not
the case. It plays the part of what is called a
" catalyst," one of the curiosities of chemistry.
There are many instances in which two things will
combine only in the presence of a third which appears
to be itself unaffected. This third substance is a
catalyst. It reminds one of the clergyman at a
wedding who unites others but remains unchanged
himself.
In conclusion, one may mention that many of the
medicines with which our injured men were coaxed
back to health and strength owe their existence to
alcohol, for many drugs are obtained from vegetable
substances by dissolving out a part of the herb with
alcohol.
Thus, as a drink, it is unquestionably very harmful.
Indeed, in that way it probably kills more people per
year than its use in the manufacture of explosives
caused in the worst year of the war. Yet it also
furnishes chloroform, ether and medicinal drugs and
performs a whole host of useful services to mankind.
Finally, if oil and coal should ever run short it is quite
prepared to run our engines for us. Truly it is a
wonderful substance.
60
CHAPTER V
MINES, SUBMARINE AND
SUBTERRANEAN
THE word mine in its military sense originally
meant just the same as it does in the ordinary
way, but like many other words it has got
twisted into new uses the connection of which with
the original meaning is very obscure. One of the most
striking of these verbal puzzles is the submarine
mine. There seems at first sight not the remotest
connection between the floating barrel of explosives
concealed beneath the water and what we ordinarily
call a mine. The explanation of this is that the term
has acquired this meaning after passing through a
series of stages.
When soldiers " mine " for the purpose of blowing
up their enemies they dig a hole in the ground, and
conceal therein a quantity of explosives so arranged
that they blow up when the enemy pass over or near.
The operation of digging the hole in the earth is
clearly akin to the work of the miner and so such is
quite appropriately called a " mine."
The hole may be dug from the surface downwards,
the marks of excavation being afterwards covered up
and obliterated as much as possible. In other cases
the hole may be a tunnel starting from a trench and
61
MINES
driving towards the enemy's position. The idea, of
course, is to burrow until the end of the tunnel is just
under some important part of the enemy's works or
fortifications. When the end of the tunnel has
reached the right spot explosives can be placed there,
the tunnel partly stopped to prevent the explosion
from driving back upon those who make it and the
whole fired at the desired moment.
This tunnelling is also called " sapping " and the
tunnel itself a sap. Military engineers are often
spoken of as "sappers and miners" as if the two
things were clearly different, but as a matter of fact
both are often used to describe the same thing.
Roughly, we may say that a mine which stays still
in the hope that the enemy will walk upon it is a
mine proper, while a mine which itself progresses
towards the enemy until it ultimately goes off
beneath him, is a " sap " and the making of such a
thing is " sapping." Or we might say that sapping
is under-mining, in which sense we use it in general
conversation when we speak of something sapping
a man's strength. Soldiers speak of their engineering
comrades as " sappers " just as they term artillery-
men " gunners," but the only reason why they call
them by that name instead of miners is because the
latter is a well-known term applied to those who
work in coal mines.
A subterranean mine, then, is nothing more or
less than a hole in the ground, made in any way that
may be convenient, filled with explosives and fired
at a suitable time to do damage to the enemy.
In other words, it is simply some explosive con-
62
MINES
cealed in the ground with means for firing it, and
when the sailor conceals explosives in the sea so that
they may blow up the enemy's ships, he borrows his
military comrades' term and calls it a " mine " too.
Counter-mining is the enemy's reply to mining.
Suppose I was foolish enough to wish to blow up
my neighbour who lives in the house opposite to
mine I might start from my cellar and dig a tunnel
under the road until I knew that I had arrived under
his dwelling. But suppose that he got to know of
my little scheme : he could then try counter-mining.
In this case it would mean starting a tunnel of his
own from his cellar towards my tunnel : then, as
soon as the two tunnels had come sufficiently near to
each other, he could let off his explosives thereby
wrecking my tunnel and putting an end to my
operations while yet I was only half-way across the
road. Thus he would stop me before I had had time
to harm him, and since he need only tunnel just far
enough to render the necessary explosion harmless
to his house, while I to succeed would have to tunnel
right across the road, the man who is counter-
mining always has a slight natural advantage over
the man who is doing the mining. If only he gets
to know what is going on in time he can always
retaliate.
All forms of land mine are improvised on the spot
according to circumstances. Not so, however, with
submarine mines on which much ingenuity has been
expended, the mines being made in workshops ashore
ready for laying and then laid by ships and some-
times by divers.
63
MINES
Of these there are two main kinds, those which are
put in place in times of peace for the protection of
particular harbours and channels, and those which
are simply dropped overboard from a mine-laying
ship during the actual war.
They all consist essentially of a case of iron or steel
plates riveted together just as a steam boiler is made,
in fact the cases are made in a boiler shop. The charge
is gun-cotton fired by a detonator, the latter being
excited by a stroke from a hammer, as in a rifle, or
else by electricity. In the latter case, a tiny fila-
ment of platinum wire is in contact with the detona-
tor, and the wire being heated by the current, just
as the filament of a lamp is, the detonator is fired by
the heat.
Of the permanent mines whereby the entrances
to important channels are protected arrangements
are often made for firing by observation, that is to
say, by the action of an observer ashore. Being laid
by divers and securely anchored to heavy weights
laying on the bottom, wires are carried from the mines
to the observation station. The observer watches
and fires the mines at the right moment by simply
pressing a key thereby making the electrical circuit.
More often, however, mines are fired by contact.
Observation mines have the advantage that while
they may be exploded under an enemy they will
allow a friendly ship to pass in perfect safety. Con-
tact mines, on the other hand, will afford protection
against attacks by night when enemy craft may
attempt to creep in under cover of darkness.
Contact mines are often fired electrically, sometimes
64
AN ITALIAN MINE-LAYER.
This photograph was taken looking down upon the deck of the ship. The mines run upon
rails, and are pushed by the men towards the stern, whence they are dropped one at a time
into the water. The splash indicates that one has just fallen.
MINES
by batteries of their own inside their own cases, or
else by current from the shore through wires, the cir-
cuit being completed by an automatic device of some
sort actuated unwittingly by the unfortunate victim.
One of these contact devices will illustrate the
general character of them all. Imagine a little vessel
with mercury in it : it is, generally speaking, of some
insulating material, but right at the bottom is a
metal stud with which the mercury makes contact.
The rim may likewise be of metal or a metal rod may
project downwards into it : it matters not which,
for we can see at once that it is quite easy so to arrange
things that whereas, while upright, the mercury shall
be well clear of the upper contact, it shall when the
vessel is tilted flow on to it, thereby bridging from lower
contact to upper contact and completing the circuit.
Of course, a mine must only go off when actually
struck by a ship and not when it is gently swung to
and fro by the action of tide or current in the water.
That is easily arranged, for the vessel and contacts
can be so shaped that contact is not made until an
angle of tilt is reached which no tide or ordinary
commotion of the water could bring about.
It is clearly possible, too, to combine the contact
and observation arrangements in such a way that con-
tact mines can be made safe for friendly ships during
the daytime. It is only necessary to adopt the shore
battery arrangement already mentioned and dis-
connect the batteries during the day or when no
enemy is in sight, restoring the connection during the
darkness or in the event of hostile ships trying to rush
the passage.
E 6 5
MINES
Another interesting scheme for keeping mines safe
until required is to anchor them in what is termed
a " dormant " condition. This means that a loop is
taken in the wire rope by which they are anchored,
the loop being fastened by means of a link. This
link, however, contains a small quantity of explo-
sive which can be fired from the shore. This has the
effect of breaking the link, releasing the loop and
allowing the mine to float upwards to the full length
of the rope. Thus the mine is down deep, well below
the bottom of the biggest ship until released for action.
It is doubtful whether much use is made nowadays
of permanent mines of the types just described, for
they have, no doubt, been largely displaced by the
temporary mine which can be laid in a moment by
simply being dropping overboard from a ship, but
it is quite possible that some of the defences of, say,
the Dardanelles, were of the permanent nature.
So let us pass on to the temporary mines. These
were used by the Germans from the first few hours
of the war. One of the first naval incidents was
when our ships discovered a small German excur-
sion steamer which had been converted into a mine-
layer strewing these deadly things surreptitiously in
the North Sea in the hope that some of our vessels
would run upon them. Needless to say, that ship
went no more excursions.
Laid thus, it is evident that there can be no wires
running ashore, so that all mines of this class must
be contact mines. What makes them of extreme
interest is the way they are laid. Just think for a
moment what is involved. From the very nature
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MINES
of things their laying must often be done in secret.
It is not the British practice to place them in the
open seas, except avowedly, after due notice, hi cer-
tain specified areas, where they are laid quite openly
under the protection of adequate forces to ensure
against interruption. There is little doubt, however,
that they have laid many a mine field secretly in
purely German waters, while everyone knows that
the Germans have not hesitated to sow the shipping
routes broadcast with these things, such work of
course being done secretly and largely at night.
The mine can therefore only be laid by dropping it
into the water and leaving it. Yet it must not float
on the surface or it will be easily seen and picked up ;
it must float below, so that the unsuspecting ship
may run upon it. And it is quite impossible to make
a thing float in water anywhere except upon the sur-
face. If it does not float upon the surface it sinks to
the bottom : there is no " half-way house " between.
Many people are surprised to hear this, judging, no
doubt, by the fact that a balloon floats in, and not on,
the air and expecting an object floating in water to
be able to do the same thing. The difference is due
to the fact that air is easily compressible, so that the
air close to the earth is denser, more compressed,
and therefore heavier, than the air higher up owing
to its having the whole weight of the upper air
pressing downwards upon it. The density of the
air diminishes, for this reason, as one ascends, and
a balloon which displaces more than its own weight
of air at the surface of the earth rises until it has
reached just that height when the air displaced
67
MINES
exactly equals in weight the balloon itself : then it
goes no higher.
Precisely the same conditions exist in the sea
except that water being incompressible is no denser
at the bottom of the sea than on the surface. There-
fore, if a thing sinks at all it sinks right to the bottom.
There is one very ingenious device for overcoming
this difficulty by means of a motor and propeller.
The mine has enclosed in its case a motor driven by
a store of compressed air which operates a propeller.
In this it is somewhat like a torpedo, but in this case
the propeller is set vertically so that its action lifts
the mine up in the water. Now the mine is so
weighted that it just and only just sinks when dropped
in, but on reaching a certain depth the motor starts
and by means of the propeller raises it nearly to the
surface again. On nearing the surface the motor stops
and the mine sinks once more, only to be raised again
in due course, so that the thing keeps on rising and
falling ; it never rises above a certain depth nor falls
below a certain depth, but oscillates continually
between its two limits.
The question then arises, what starts and stops
the motor at precisely the right moments to produce
this result ? It is done by means of a hydrostatic
valve. As just pointed out, the water at the bottom
of the sea is supporting the weight of all that water
which is above it. The water is not compressed by
this, but the pressure is there all the same. Obviously
the degree of pressure at any point depends upon the
weight of the layer of water above, and since the
weight of that layer will obviously increase and
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MINES
diminish with its thickness it follows that, starting
from the surface, where the pressure is nil, we get a
perfectly steady and regular increase as we descend,
until we reach the maximum at the bottom. Now
within the mine is a small watertight diaphragm,
the outer surface of which is in contact with the water
and upon which, therefore, the water presses. As
the mine descends, therefore, this diaphragm is bent
inwards more and more by the pressure of water and
that is made to start the motor. Adjustments can easily
be made so that a certain degree of bending shall
result in starting the motor, which is the same as
saying that the motor shall start automatically at a
certain depth. Likewise as the mine rises under the
influence of the propeller the pressure decreases, the
diaphragm straightens out and at a certain pre-
determined depth the motor is stopped.
When, finally, the store of motive power is ex-
hausted the mine sinks to the bottom and is lost, a
very valuable feature from a humanitarian point of
view, since it means that the active life of the mine
is short and it cannot go straying about the oceans
for weeks or even months, finally blowing up some
quite innocent passenger ship.
More often, however, this difficulty of depth is
overcome by anchoring the mine at the depth most
suitable for striking the bottom of a passing ship.
But here again there seem to be insuperable diffi-
culties, for the depth of the sea varies and so the length
of the anchor rope must be varied with almost every
mine that is laid. It has been found possible, how-
ever, to make the mines automatically adjust the
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MINES
length of their own anchor ropes so that the desired
result is attained without difficulty no matter how
deep the sea may be. Let me describe how it is
done in the Elia mines used by Great Britain. The
inventor, Captain Elia, was an officer in the Italian
Navy.
The mine consists of three parts : (1) the mine
proper, a case containing the explosive, gun-cotton
and the firing mechanism ; (2) the anchor ; and (3)
the weight, all of which are connected together by
suitable wire ropes.
The mine is lighter than water and so floats : the
anchor, which bears no resemblance to the ordinary
anchor but which is an iron case containing mechan-
ism, only able to act as an anchor by virtue of its
weight, is heavier than water and so sinks, while the
weight of solid cast iron sinks more readily still.
The anchor is often fitted with wheels so that it
forms a truck upon which the mine and the weight
are placed, the whole running upon rails laid on the
deck of the mine-layer. As this ship steams ahead
the men push the mines along the rails, dropping
them over the stern at regular intervals.
When the thing reaches the water, the weight sinks
the most rapidly, thereby tugging at the chain
whereby it is connected to the anchor. The latter,
being less compact, sinks more slowly so that the
pull upon the rope is maintained until at last the
weight rests upon the bottom. Then and only then
is the pull relaxed. Now inside the anchor is a winch,
upon which is wound a length of flexible wire rope,
the other end of which is attached to the mine.
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MINES
The latter, it will be remembered, is light enough to
float and so, since it lies upon the surface while the
anchor sinks, the rope is drawn off the winch. But
there is a spring catch which is able to hold the winch
and to prevent it from paying out rope, and that
catch is only held off by the pull of the weight. Con-
sequently, as soon as the weight touches the bottom
and its pull upon the anchor ceases, the winch is
gripped by the catch, no more rope is paid out, and
from that moment, as the anchor descends, it drags
the mine down with it.
The result, then, is that the mine becomes anchored
at a depth below the surface roughly equal to the
length of the rope connecting weight to anchor.
Mines of this kind can, of course, be fired electrically
by the tilting of a cup of mercury or similar device
as already described. Another arrangement is to fit
projecting horns upon the surface of the mine made
of soft metal so that they will be bent or crushed by
a strong blow such as a passing ship would give. This
breaks a glass vessel inside, liberating chemicals which
cause detonation.
The method adopted in the Elia mines is to have
a projecting arm pivoted upon the top of the mine.
The mine is spherical (they are nearly all either
spherical or cylindrical), with the rope attached to
the South Pole, so to speak, and the arm pivoted
to the North Pole. As the mine floats in the water
the arm projects out horizontally. The effect of this
arrangement is that when a ship strikes the mine
the latter rolls along its side, but the arm being too
long, simply trails along. Thus the spherical case of
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MINES
the mine turns while the arm remains still and
that is made to unscrew and eventually release a
hammer which, striking the detonator, fires the mine.
In other words, this type of mine is exploded not
by the ship giving it a blow, but by its rubbing itself
along in contact with the mine. The great advantage
of this is that it is only a ship that can do this. No
chance commotion in the water can do it : no chance
blow from floating wreckage can do it : only the rub-
bing action of a ship can accomplish it. Such a
mine, too, is less likely to be affected by counter-
mining, of which more presently.
Apparently the laying of these mines must be very
dangerous work, for since a blow will explode most
of them, what is to prevent their receiving that blow
while on the deck of the mine -layer, or at all events
as they are dropped into the water.
In all cases, precautions are taken against such an
event. Sometimes a hydrostatic valve is employed,
the arrangement being that the firing mechanism is
locked until released by the valve, until, that is, the
mine is immersed to a predetermined depth in the
water.
Another device for the same purpose is a lump
of sugar. The mine is so made that it cannot be fired
until this lump has been melted by the action of the
water : sal ammoniac is another substance employed
for the same purpose. The technical term for this
is a " soluble seal." The firing arrangement, what-
ever it may be, is sealed up so that it cannot come
into operation until the seal has been dissolved away
by the water, or until the mine has been in the water
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MINES
long enough for the mine-layer to get out of harm's
way.
Another interesting feature of the Elia mine is
connected with the source of the power which drives
the hammer which causes the explosion. The anchor,
it will be remembered, pulls the mine down under
water, the latter being of itself buoyant. There is
a continual pull, therefore, upon the rope by which
the mine is held under. It is that pull which works
the hammer.
And now observe the beautiful result of that simple
arrangement. Suppose the mine breaks its rope and
gets loose, so that it can drift about and carry danger
far and wide. It can break loose and it can drift
about, but at the very moment of getting loose the
danger vanishes, for the rope ceases to pull and the
firing mechanism loses its motive power.
In other mines the same result has been sought
by means of clockwork, which throws the firing
arrangements out of action after the lapse of a given
time. This scheme of Captain Elia's, however,
whereby the very act of breaking adrift produces its
own safeguard, is one of the most delightful instances
of a happy invention.
In conclusion, just a word about the measures taken
against mines. Counter-mining is one. It consists
in letting off other mines in the midst of a mine-field
with the purpose of giving them such a shaking up
that some of them will be exploded by the shock.
The simplest and indeed the only effective way,
however, seems to be the simple primitive method
of dragging a rope along between two light draught
73
MINES
vessels and thus tearing the mines up by their roots,
so to speak. The very act of thus dragging it along
by its anchor rope often causes a mine to explode,
well astern of the mine-sweeping vessels, but some-
times they are pulled up and fired or sunk by a shot
from a gun which the sweeper carries for the purpose.
The sweeping up of the mine-fields is a duty often
allotted to the steam fishing boats or trawlers, whose
crews seem particularly well fitted for the work. It
is a hazardous duty, and many lives have been lost
through it. Let us hope that in time to come all
submarine mines and the dangers connected with them
will be a thing of the past, for they are mean, cowardly
and contemptible weapons.
74
CHAPTER VI
MILITARY BRIDGES
BRIDGING has always been an important part
of actual warfare. In my school days I
studied " Csesar " from a textbook which is
not much in use nowadays and which had very
copious notes, prominent among which was a de-
scription, with drawings, of a bridge made by the
Roman Legions in Gaul. And a fine bridge it was,
too. How its details came to be known was partly
through the description given by Caesar himself and
partly by a study of certain old timbers found in the
bed of the Rhone, which timbers were believed to be
relics of the very bridge which the great Julius
himself had had built.
This bridge of nearly two thousand years ago
appeared to be built of baulks of timber fastened
together in very much the same manner as that
adopted by the engineering units of the great armies
of to-day.
Every observant person has noticed how tall poles
and short sticks tied together with ropes can be
fashioned into the firm, strong scaffolding from which
workmen can in safety raise great tall buildings.
That mode of construction can always be used to
form a. bridge.
Equally well known, no doubt, are the gantries
75
MILITARY BRIDGES
built over the footway while a large building is in
course of construction. Generally of huge square
baulks of timber, they are intended to carry very
heavy loads of materials and to save the public
passing beneath from any possibility of damage
through heavy objects falling from above. Those
gantries furnish us with an example of another sort
of construction in wood which can be and is often
used in bridging.
When the Germans retired in Northern France
they blew up all bridges behind them, and before the
Allies could use those bridges they had to repair them.
If only for foot-traffic, a contrivance of poles, lashed
together after the manner of the builder's scaffold, is
ample in most of such cases and by its means a
strong and safe bridge can be made upon what is left
of the old bridge in the course of a few hours. For
light vehicles a similar structure but made stronger
by more lashings and of poles closer together will
suffice, but for heavy traffic, with guns and possibly
railway trains, recourse has to be had to the heavy
timberwork exemplified by the builder's gantry.
This takes longer to make, since the timbers are big,
heavy and not easy to move about : they are, more-
over, not simply laid beside or across each other and
tied, but are cut the right lengths, and one is notched
where the end of another fits into or against it. The
baulks are connected by bolts and nuts for which
holes have to be drilled or by rods of iron with a
sharply pointed prong on each end stretching across
from one baulk to another, one prong being driven
into each.
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MILITARY BRIDGES
With the long-thought-out military operations of
modern warfare it is just possible that steelwork for
repairing certain particular bridges might be pre-
pared in advance and simply launched across when
the time arrives, but that is manifestly impossible
except in certain cases and under particularly
favourable conditions, such as railway facilities for
bringing up the new bridge close to the site where it
is to go.
Nearly every military bridge therefore has to be
more or less improvised on the spot. In a highly
developed country scaffold poles or baulks may
be found or brought up by road or rail, in less
civilised lands their equivalents may be cut and pre-
pared from neighbouring forests, but all armies have,
as a recognised part of their organisation, certain
engineering " field companies," and " bridginv
trains," which carry with them large quantities of
material carefully schemed out long in advance, so
shaped and so prepared that it can be fashioned into
almost anything, much as the strips of a boy's
" meccano " can be adapted to form a great variety
of objects.
First, there are pontoons, large though light boats
or punts, about 20 feet long, constructed of thin
wood with canvas cemented all over to give additional
strength and water-tightness. Each pontoon ridas
upon its own carriage upon which there are also
stowed away quantities of timbers of various sorts,
anchors for holding the pontoons in place, oars for
rowing them, ropes of different kinds, and so on.
Each pontoon, moreover, is divided about the
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MILITARY BRIDGES
middle into two pieces called respectively the bow
piece and the stern piece. The two are normally
coupled together by cunningly devised fastenings but
they can be quickly separated, in which state they
form two shorter boats.
Other carriages carry more timber and material
intended for the purpose of forming " trestle
bridges " but which is also usable in connection with
the pontoons.
Of this material the chief sorts are " legs," long
straight pieces which form the uprights ; transomes,
heavier beams which can be fitted across horizontally
between two legs so that the three form a huge letter
H or a very robust Rugby goal; "baulks" which
are light timbers tapered off towards each end for
the sake of lightness and of such size that they fit
snugly into notches which are cut in the upper
surface of the transomes ; and planks called
" chesses" for forming the floors of a bridge.
Probably the most dramatic incident of the war
was when the British, having been apparently beaten
by the Turks in Mesopotamia, driven far back and
their General and many troops captured, suddenly
turned the tables upon their enemies, driving them
from Kut and sending them fleeing helter-skelter to
Bagdad and then beyond. Now the capture of Kut
and then of Bagdad were both made possible by the
rapid bridging of the Tigris, and without doubt this
is the sort of material which was used. Let us see how
it is done.
An army arrives at a river across which it is
decided to throw a pontoon bridge. The pontoons are
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MILITARY BRIDGES
unloaded off their wagons and launched into the
water. One is rowed out and anchored a little way
from the shore, while upon the bank parallel with the
river is laid a " transonic." On the centre of the
pontoon is a centre beam with notches in it like
those in the transomes and from the one to the
other " baulks " are passed. Meanwhile a second
pontoon has been rowed into place and more baulks
are passed from the first pontoon to the second, while
chesses are laid upon the baulks to form a platform or
floor.
Thus, pontoon by pontoon, the bridge grows until it
has reached the further bank.
If pontoons are scarce and the loads to be carried
by the bridge are light they are divided in two, and
instead of a row of pontoons joined by " baulks "
there is a row of " pieces " joined by baulks. Pieces
arranged thus form a light bridge, pontoons a medium
bridge, while pontoons placed closer together form a
heavy bridge. Which shall be built depends upon
the number of pontoons available in relation to the
width of the river and the nature of the traffic which
will have to pass over.
An alternative arrangement is to make the pontoons
up first into groups or rafts and then bridge from
raft to raft instead of bridging between pontoons.
There is still another way of making the bridge,
and that is to put it together alongside the bank,
afterwards swinging it across the river like the
opening or shutting of a door. Anyone can see that
there must be many advantages in this latter method
when it is practicable, since more men can work at
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MILITARY BRIDGES
once and with greater safety, for all will be near
the bank.
It is evident that such a structure depends for its
security entirely upon the anchors. Those which are
carried for the purpose are like those of a ship but
there may not be enough or they may not suit every
kind of river-bed. They are often improvised there-
fore. Two wagon wheels lashed together, with heavy
stones clipped between them, are said to be a very
effective anchor. Under certain conditions a net
filled with stones is surprisingly effective. Two
pickaxes tied together form a good imitation of the
conventional anchor, as also does a harrow sunk and
held down by stones thrown upon it.
Trestle bridges are made in quite a different way.
The trestles are formed of two legs or uprights with a
transome between, a shape which resembles, as has
been already remarked, a very robust Rugby goal.
The transome is connected to the legs by a special
form of band which permits it to be fixed at any
height without having to drill any special holes for
the connections. The legs are so shaped at their ends
that they can be shod with steel shoes provided for
the purpose, enabling them to get a good foot-
hold even on shifty soil. The trestles are put together
ashore, and each is taken out in a boat or on a
pontoon to the place where it is to stand. Then it is
launched feet foremost into the water, the boat being
on the side away from the shore, so that a rope from
the trestle to the shore will enable men on land to
pull the trestle into an upright position.
Thus trestle after trestle is added until the bridge
80
AN INCIDENT AT Loos.
This picture gives us some little idea of the devastation caused by modern weapons. It also shows
the inventiveness of the soldier who makes his rifle into a battering-ram. Incidentally we see a
kind-hearted soldier rescuing a little girl from danger. This incident really happened.
MILITARY BRIDGES
has grown right across the water to the further bank.
The trestles cannot fall over sideways because of
their own width, they cannot fall forwards or back-
wards because of the " baulks " which pass between
them and carry the floor, but as a precaution
diagonal ties of rope are always added here and
there along the bridge, that is to say, two trestles
are tied together with two ropes, each rope passing
from the bottom of one trestle to the top of the
other, a form of tying which is very effective and very
easy and simple to carry out.
One interesting thing to notice is the form of the
" baulks," in which connection I would like to
remark that when I use the word without inverted
commas I mean it in the ordinary sense as implying
a big heavy timber, but when I use the commas I
mean it in its technical sense as it is used in military
engineering. In this latter sense it describes the
timbers specially provided for the purposes just
described. Large supplies of the ordinary heavy
baulks could not be carried with an army : but
strength is required nevertheless. Hence the
military engineers have invented a form which
combines strength with lightness.
If you stand a plank upon its edge, supported at
each end so as to form a beam, its strength will vary
as its width and as the square of its height. If then
you double its width you only double its strength, but
if you double its height you multiply its strength four
times. If you halve the width of a given beam you
halve its strength, but if you then double its height
you quadruple that half, in other words, without
F 8l
MILITARY BRIDGES
making the beam any heavier by these two opera-
tions you double its strength. Moreover, if you
support a beam at each end and pass a load over it
or spread a load permanently upon it, its greatest
strength is required in the middle. You can shave
away the ends without making the beam as a whole
any less strong. So these " baulks " are made like
planks, very oblong if looked at endwise, also thinner
at the ends than in the middle. But if by chance
they tipped over on to their sides they would for that
very reason be very weak, and that is why the
notches are provided in the transomes and the centre
beams of the pontoons, in order that the " baulks,"
having been laid edgewise in them, cannot tip over.
Thus a considerable saving is made in the weight of
the bridging material to be carried.
It sometimes happens that when a trestle is
dropped into the water one leg will fall into a
depression in the river-bed or will sink more deeply if
the bed be soft, leaving the whole structure lop-
sided and useless. That, however, is easily overcome,
since it is provided against. A little iron bracket,
which is carried for the purpose, is clipped on to the
leg which has sunk near its top and on to it is hung a
pair of pulley blocks one of those little contrivances
which everyone has seen at some time or another by
which one man pulling a chain quickly can raise,
although slowly, a heavy load. By this means the
end of the transome is raised until it is horizontal and
the legs have assumed an upright posture, when the
transome is refastened to the leg in its new position.
Thus we see the advantage of clamping the transome
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MILITARY BRIDGES
to the leg rather than fixing it with any arrangement
of holes. The iron band, which is fastened on to the
transonic and which grasps the leg, is so arranged
that the greater the load the more tightly does it hold,
so that it is perfectly safe under all conditions.
The trestle bridge has a great advantage over the
floating bridge if the height of the water varies at all,
as for instance, with the tide. The former remains
still, while the latter goes up and down, requiring a
special arrangement to be contrived for connecting it
to the shore.
Under some conditions a suspension bridge is the
most convenient form of all, particularly if the banks
are high and strong, or if the current be very rapid or
the river-bed very soft. In such cases steel wire ropes
are stretched across the water between two trestles.
The latter may be made in the way just described,
but more often they have to be stronger and are built
specially out of big strong timbers securely fastened
together. Their form does not matter much so long
as they are strong and stiff, high enough to carry the
ends of the suspension ropes and of such a shape as
not to block the entrance to the bridge itself. The
higher they are the better, because, according to the
natural laws which govern such things, the more
sag or dip there is hi the ropes across the river the
less severely will they be strained. They need to be
very strong, as the whole weight of the bridge and its
load falls upon their shoulders. The pull of the
suspension ropes, moreover, tends to pull them
forward into the water, so they must be held back
by other strong ropes called guys, and the action of
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MILITARY BRIDGES
these two sets of ropes entails the unfortunate
trestles bearing really more weight than the actual
weight of the bridge and load. The guys, too,
require very strong anchorage or at the critical
moment they may give way, when the whole con-
trivance, with possibly valuable guns or ammunition
on board, will be precipitated into the water. The
men may be able to swim but the guns will sink.
Having, then, constructed a trestle upon each bank,
securely guyed it back and connected the suspension
ropes to it, the next operation is to attach smaller
vertical ropes to the suspension ropes at intervals, to
support the ends of the transomes. Then upon the
latter are laid " baulks " and upon them the flooring
as usual. Or if ropes be not sufficiently plentiful,
timbers may be lashed on to the suspension ropes
instead, the transomes being fastened to them.
That is all that is absolutely essential to a suspen-
sion bridge, but one so formed would be rather flimsy
and unstable. It needs to be stiffened by diagonal
timbers at suitable places and often it has props
placed upon the bank reaching out as far as their
length will permit over the water to steady and con-
solidate what to commence with is rather too much
like a spider's web. Those little strengthening dodges
can be laid down in no books. They need to be left
to the judgment of the men in charge to do what is
necessary in the best way they can with the materials
which happen to be at hand.
But very often warfare has to be carried on in the
most outlandish places where armies can only travel
light, and where, hampered by bridging material of
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MILITARY BRIDGES
the conventional sort, they would have no chance in
catching up with a fleet and agile native enemy. Yet
bridges are needed even more under those conditions
perhaps than under any other. There are many
examples of this in the wars just beyond the frontier
in Northern India. Then ingenuity has to make good
the luck of prepared material and the bridges are
made of those materials which happen to be pro-
curable.
An army in India once wanted to cross a river,
where no materials of the ordinary kind were avail-
able. The river, however, was lined with tall reeds.
A reed has for centuries been a favourite example of
weakness and untrustworthiness, so how can reeds be
made to form a safe bridge ? This is how it was
done.
Great quantities of reeds were cut and were made
up into neat round bundles about a foot in diameter.
Ropes were scarce too, but these likewise were impro-
vised by twisting long grasses into ropes. It is
surprising what good ones can be made in this way,
and they served their purpose well. Many bundles
having thus been made numbers of them were tied
together so as to form rafts. Each bundle in fact
was a small pontoon, and the rafts which were thus
constituted differed only in size from the regulation
rafts made of pontoons.
While this work was being done two ropes were
got across the river and secured on both banks : then
rafts were floated down in succession, each one on
arrival being tied up under the two ropes. Finally
a track of boards was laid over the centre and the
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MILITARY BRIDGES
bridge was strong enough for men in fours to walk
over it.
Had it been necessary, the floor could have been
made of brushwood, interlaced so as to form a kind
of continuous matting or of a layer of branches
covered with canvas. Floors for bridges can be made
in many ways.
A dodge which soldiers in the British Army are
taught is how to make boats for bridging purposes
out of a tarpaulin or piece of canvas, supported on a
framework of light wood poles or twigs. The outline
of the boat is first drawn roughly on the ground.
Then three posts are driven in on the centre line of
the boat and to the top of these three a horizontal
pole is tied, thin, flexible branches stripped of their
bark, being fixed by having their ends stuck in the
ground on either side. The ends are driven in on the
outline already marked out so that when done the
branches form a framework like the ribs of a boat
upside down. Other branches are intertwined
among these so as to bind them together and finally
a tarpaulin or canvas sheet is laid over all. A number
of boats formed after this fashion can be used as
pontoons to support a bridge, or several can be made
into a raft and towed to and fro a sort of floating
bridge.
Another scheme is to make a number of crates like
those in which crockery and other things are often
packed. These are of very simple and easy con-
struction, consisting of sticks slightly pointed at the
ends driven into other pieces which are perforated
with suitable holes to receive the ends. The only
MILITARY BRIDGES
tools necessary are an axe (or even a pocket-knife
will do) to sharpen the ends and an auger to make
the holes. Almost any sort of wood can be made to
serve. The cover for this, and indeed for most of
these improvised rafts, is tarpaulin or canvas, the
latter of which, being the material used for so many
purposes, is almost sure to be available in some form
or other.
For instance, every one of those familiar " General
Service Wagons " has its large canvas cover. In
fact, a general service wagon, taken off its wheels and
wrapped up in its own canvas cover, makes quite a
serviceable boat, pontoon, punt, barge or whatever
you like to call it.
Then there is an ingenious type of little bridge
which can be quickly and easily made where bamboos
or similar light canes or sticks are available. The
only tool required in making this is a couple of poles
ten feet or so in length. To commence with, these
poles are laid side by side upon the bank with one end
of each pointed out over the water, overhanging it
by about four feet. Two men then climb along these,
while others sit upon the inshore ends to keep them
from tipping into the water.
Seated, then, on the outer ends of the poles the
men drive some bamboos or whatever they are
using into the water, after which they tie a cross-
piece to the uprights, so forming a light trestle. Then
the poles are pushed forward until they overhang
another four feet beyond the trestle just made, the
other men, of course, continuing to sit upon the rear
ends. And so the bridge grows until it entirely
crosses the stream,
87
MILITARY BRIDGES
Between the trestles other light poles are laid and
tied, forming the floor upon which men can cross in
single file.
Another type, known as the " hop pole " bridge is
made of slightly heavier poles which are tied together
in threes so as to form isosceles triangles. Each
triangle forms one trestle.
The two poles which form the sides project a little
above the apex so that in fact we have an isosceles
triangle with a V at the apex. To the root of the V
another pole is tied loosely and the whole trestle is
pushed feet first into the water. Then, by pushing
the pole, it is forced into an upright position in
which it is secured by the pole being firmly fixed to
the shore and strongly lashed to the root of the V
where, before, it was only loosely tied. A second
trestle is then in like manner fixed in front of the
first one, connected to it by a pole just as the first is
connected to the bank. And so the thing grows. To
all the upper ends of the V's a light pole is tied to
form a handrail. In this case, of course, the floor of
the bridge is nothing more than a pole, but with the
assistance of a handrail it is quite easy to walk along
a single pole.
And that reminds me of a simple type of suspen-
sion bridge which, an engineer officer once assured me,
is actually copied from one habitually made by some
of the Indian natives. It consists of three ropes
upon one of which you walk, while the other two
form a handrail upon either side. The three ropes
are held at intervals in their correct relative positions
by little wooden frames formed of three sticks tied
88
MILITARY BRIDGES
together, one rope being tied to each corner of each
triangle.
On the banks stakes are driven in and tied back
with cords to give additional strength, and to them
the ends of the ropes are secured. One drawback to
this form of bridge is that the ropes are naturally
far from level and one has to walk down a steep hill
to commence with and up again at the other end.
I once saw a specimen of this kind of bridge across a
wide ditch, a part of the old defences of Chatham, and
an elderly gentleman who was with me, a man of
considerable proportions, insisted upon trying it for
himself. He took but a step or two when his foot
began to slide downhill along the foot rope faster
than he dare move his hands along the hand ropes,
with the result that he was very soon in a very
uncomfortable position. Thus he remained, to the
amusement of all his friends, until two stalwart
Royal Engineers came to his aid and " uprighted "
him.
In crossing a swamp something in the nature of a
bridge is sometimes required. Canvas laid upon
branches often makes a good road over what would
otherwise be impassable.
Rapidly moving detachments of cavalry are pro-
vided with what is called " air-raft equipment,"
which enables them to get their light " Horse
Artillery " guns across rivers which would be im-
passable otherwise. It consists of sixty bags like
huge cylindrical footballs except that the outer
covering is canvas instead of leather. These are
blown up partly by the mouth and partly by pumps
89
MILITARY BRIDGES
provided for the purpose until they are just about as
tight as a football should be. Then they are laid out
in rows of twelve, each row being fastened together by
the bags being tied to a pole running lengthwise of
the row. Cords are attached to the bags for the
purpose. The five rows are then placed parallel and
connected together by two light planks called wheel-
ways placed across the rows and tied thereto.
This arrangement is capable of carrying light guns
or ammunition wagons. The men are expected to ride
through the water, but if necessary something can be
laid upon the raft, between the wheelways, to form a
floor upon which men and even horses can ride.
As part of the equipment there is a small collapsible
boat with oars and by its means men first cross,
carrying with them a line by which, afterwards, the
raft can be hauled to and fro.
Rafts can be made, too, of hay tightly tied up in
waterproof ground-sheets or tarpaulins or canvas.
Indeed, given a little ingenuity and the need to use it
(for it is very true that necessity is the mother of
invention), it is surprising what a large variety of
things can be pressed into this service.
Of course, barrels can be made to form excellent
pontoons, but there is one clever little way of using
them which is more than usually interesting, and
with that I must conclude this chapter which has
already exceeded its appointed limits.
Imagine two poles perhaps ten feet long, placed
parallel. Between them, at one end, a barrel is
lashed : at the other end is a plank forming with the
poles a T. A man can then sit upon the barrel and
90
MILITARY BRIDGES
paddle about, for the poles and planks will steady
the barrel just as the outriggers and floats steady the
narrow canoes or catamarans of which we read in
books of travel. For that reason a bridge formed of
such is called a " catamaran " bridge. Of course, if
there are only a few barrels to be had they can be
fitted out like this and then combined into a raft.
Or if there are enough of them they can be anchored
at intervals and poles or planks laid from one to
another so as to form a continuous bridge. Or a single
one may be used as a boat. I can almost fancy I see
some of my readers who have access to a pond rigging
upjan^old barrel in this way, just to see how it goes.
CHAPTER VII
WHAT GUNS ARE MADE OF
NO longer ago than the days of the Crimea,
the largest guns were made of the cheapest
and commonest kind of iron, that known
as cast iron.
This material has the advantage of being cheap
and easily worked, but is comparatively weak and
liable to crack, so that the guns of that time were
comparatively small compared with those of to-day ;
they could only withstand a feeble explosion and
their range was therefore limited. Had the ener-
getic explosives of the present time been employed
in them they would inevitably have burst, killing
their gunners instead of the enemy. Attempts were
made to strengthen them with bands made of wrought
iron, a form of the metal which is tough and elastic
and therefore better able to withstand sudden
shocks than the more brittle cast iron, but it was
not a real success.
At first sight one naturally wonders why the
whole gun was not made of the stronger wrought
iron. The reason was that while cast iron can be
melted and poured in a liquid form into a mould, so
as to produce the shape of the gun, wrought iron will
not melt. It will soften with heat, in which condition
92
WHAT GUNS ARE MADE OF
it can be hammered into shape and, moreover, when
in a very soft state two pieces can be joined by simply
forcing them closely together, which operation is
called welding.
With the machinery available now it would be
possible to make a gun of wrought iron, but even a
few years ago it would have been quite impossible.
There was an obvious need therefore of a metal which
could be melted and cast in moulds like cast iron,
yet tough and strong to resist shock like wrought
iron. Fortunately this problem excited the interest
of a certain Mr. Henry Bessemer, a gentleman who,
having made a considerable fortune through an in-
genious method of manufacturing bronze powder,
had sufficient leisure and money to devote himself
to its solution.
The vast steel industries of Great Britain and the
United States are the direct results of this gentle-
man's labours, and in the latter country there are
quite a number of towns which, being the home of
steelworks, are called by his name.
Iron is one of the most plentiful things in the
world. Deposits running into millions of tons are
to be found in many parts, but it is practically
always in the form of ore, that is to say, in combina-
tion with something else generally oxygen and
sometimes oxygen and carbon. The former sort of
ore is called oxide of iron and the latter carbonate of
iron, and both of them bear not the slightest resem-
blance to the metal. They are just rocks which form
part of the earth's crust, and it is only the metallurgist
who can tell what they consist of.
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WHAT GUNS ARE MADE OF
In order that the iron may be obtained from the
ore it is necessary for the oxygen to be separated
from it, an operation which requires the intervention
of heat, and the heat must be obtained from a fuel
which consists mainly of carbon. Wood fulfils these
requirements, but there is not enough wood in the
whole world to smelt all the iron which we need. It
was not until " pit-cole " displaced " char-cole " (to
use the spelling of the period) that the iron industry
began to assume its present importance.
To produce iron cheaply, therefore, ore and coal
should for preference lie side by side, and in some
few favoured localities that state of things exists.
Generally speaking, however, the ore and the coal
are not found together, with the result that one has
to be taken to the other, and in practice it is usually
the ore which is taken to the coal. Hence, the iron
and steelworks are generally to be found on the coal-
fields, while the ore comes by rail or ship from, it may
be, remote parts of the world.
The method by which the metal is obtained from
the ore is in principle very simple. Coal and ore are
mixed together in a furnace, the fire being fanned by
a powerful blast of air. The result is that the bonds
uniting iron and oxygen are relaxed by the heat,
when the oxygen, having a preference for union with
carbon rather than with iron, leaves the latter to join
up with some of the carbon of the coal.
The furnace in which this operation is carried out
is a tall, vertical cylinder of iron, lined with fire-
brick. The fire is at the bottom and the fresh fuel
and ore are thrown in at the top. As the ore is
94
WHAT GUNS ARE MADE OF
" reduced " (the chemist's term for removing oxygen
from anything) the liquid iron accumulates in the
lowest part of the furnace, whence it is drawn off at
i. ntervals, being allowed to run into grooves or
gutters in a bed of sand, where it solidifies into what
is called " pig iron."
Along with the coal and ore, there is thrown into
the furnace from time to time quantities of lime-
stone which combines with the earthy impurities
with which the ore is contaminated. Together these
form what is called " slag," which also exists, while
in the furnace, as a liquid, but is so much lighter than
the molten iron that it keeps quite separate and can
periodically be drawn off through a hole higher up
than that through which the iron is obtained. The
slag solidifies into a hard stone which is broken up
and used for making concrete and tar-paving, also
for road metal.
The kind of furnace just described is, owing to the
strong blast of air needed for its operation, called a
" blast-furnace." One would be inclined to think
that a fire so well supplied with oxygen, both from
the blast and from the ore itself, would cause the
fuel to be completely burnt up, yet such is not the
case. The gases which ascend from the fire consist
largely of " carbon-monoxide," a burnable gas with lots
of heat still left in it. Years ago, and one may still
see instances of it, this gas was allowed to escape at
the top of the furnace, where it burnt in the form of a
huge flame. In most modern furnaces, however,
there is a kind of plug in the orifice at the top which,
while it can be lowered in order to admit the ore and
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WHAT GUNS ARE MADE OF
fuel, normally prevents the escape of the gases, which
are led away through pipes. In some cases the gases
are burnt under boilers to provide the works with
steam, in other cases they heat other furnaces for
metallurgical purposes, while in yet others they are
employed to drive large gas-engines to generate
electricity. It is sometimes a difficulty to find
useful employment for the vast quantities of this
" blast-furnace gas " which are produced at a large
works.
We see, then, how is obtained the pig iron from
which the other kinds of iron and steel are made.
It is not pure iron by any means ; indeed, it is not
sought to make iron pure, as is the case with most
other metals, since, in its pure state, it is too soft to
be of much use. All the familiar forms of iron and
steel are really alloys of iron and carbon, a fact which
tends to give iron its unique position among the
metals, since by exceedingly slight variations in the
percentage of carbon we can vary the properties of
the iron to an amazing extent, thereby producing in
effect a wide range of different substances each
particularly suitable for a particular purpose.
To make cast iron, such as the guns of the Crimea
were made of, it is only necessary to melt up some
pig iron and to pour it into a mould. There is
scarcely a town in which there is not an iron foundry,
either large or small, and that is the work carried on
there. A smaller form of the blast-furnace, known
as a " cupola," melts the pig iron, and the moulds
are generally made of sand. The process of pouring
the melted metal into the moulds is called "casting"
96
WHAT GUNS ARE MADE OF
and the things so produced are " castings," and are
said to be made of " cast " iron.
Wrought iron is made by working the molten pig
iron instead of casting it. The work is done in a
different type of furnace altogether from the blast
furnace and the cupola. It is more like an oven, in
the floor of which is a depression wherein the molten
metal lies. The fire-place is so arranged that the
flames pass over the metal, being deflected downwards
upon it by the roof as they pass.
It should be understood that in casting pig iron one
does little more than form it into some desired shape,
the nature of the metal undergoing little or no change.
In working it, however, into wrought iron, we
change its nature.
The pig iron contains from 2 to 5 per cent of
carbon, which it obtains from the coal in the blast-
furnace, and it is this particular proportion of carbon
which gives it its own peculiar properties. To con-
vert it into wrought iron a workman puts a long iron
rod into the furnace and stirs the metal about, thereby
exposing it to the air and permitting the carbon
to be burnt out. As it loses carbon the iron becomes
less and less fluid until it reaches a sticky stage.
Thus the workman, who is known by the name of
puddler, as the process is called puddling, works up a
ball of decarbonized and therefore sticky iron upon
the end of his rod. Having thus produced a rough ball
or lump he draws it out of the furnace and leaves it
to cool.
Thus the result of the puddling process is to
produce a number of rough lumps or balls of iron
G 97
WHAT GUNS ARE MADE OF
with only about one-tenth per cent of carbon. They
are next reheated, in another furnace, and a number
of them are hammered together under a mechanical
hammer into larger lumps called blooms or billets.
The hammering process has the effect of driving out
impurities and also of improving the texture of the
metal.
Iron sheets, bars, rods and so on are formed by
heating the billets and rolling them out in powerful
rolling mills, machines which in principle are pre-
cisely similar to the domestic mangle, wherein two
iron rollers with properly shaped grooves in them
squeeze out the billet into the desired form.
Wrought iron, owing to the method by which it is
produced, is not homogeneous, that is to say, it is
noi" quite the same all through, with the result that
when it is rolled it develops a grain somewhat
similar to the grain in wood, so that if bent across
the grain it is somewhat liable to crack. On the
other hand, it has the advantage over steel that it
rusts much less readily. Hence, for outdoor purposes
it is still sometimes preferred to the otherwise more
popular steel.
Now the problem which Bessemer set before him-
self was to find out how to make a metal which could
be cast like cast iron yet should be as strong and
tough as wrought iron. After a little experimenting,
by a happy inspiration, he hit upon the idea of
blowing air through a mass of molten pig iron,
thereby burning out the carbon, just as is done in the
puddling process, only much quicker and with less
labour. By this means he produced a metal with
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WHAT GUNS ARE MADE OF
less carbon than cast iron and more than wrought iron,
a sort of intermediate state between the two, and
to his joy he found that this " Bessemer steel " could
be cast like cast iron yet had strength and toughness
equal to if not superior to that of wrought iron.
Moreover, it was homogeneous and when rolled did
not possess the troublesome grain characteristic of
wrought iron.
Having thus found the way to make this new and
desirable metal, Bessemer encountered a great
disappointment, so great that it would have entirely
beaten many men. He made samples of steel and
submitted them to experts in iron manufacture.
Everyone thought them admirable and many large
iron works were induced by them to make arrange-
ments with Bessemer for the right to use his process.
His name was already famous and it seemed as if a
new fortune was made, when, to his alarm, he
learned that wherever it was tried except in his own
works, the process was a miserable failure. Instead
of being at the end of his labours he was just at the
beginning.
It turned out that the particular iron which he
happened to buy and use at his own works was
particularly free from an impurity which is, generally
speaking, a great nuisance in iron, namely, phos-
phorus. It was pure accident which had led him to
use this iron : it happened to be the kind he could
purchase most easily in the small quantities needed
for his experiments but it led him into a great
difficulty, for other people, after paying him for the
right to use his process and after spending large
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WHAT GUNS ARE MADE OF
sums on the requisite plant, found themselves unable
to make the steel because of the phosphorus in their
iron and finding themselves unable to make a success
were inclined to write him down a fraud. As it
turned out, after much labour on Bessemer' s part,
it was due to the presence of tiny percentages of
phosphorus in most of the iron that is produced.
After much trouble he was able to induce certain
owners of blast-furnaces to make, by special methods,
a kind of pig iron practically free from phosphorus
and therefore suitable for his process. This special
pig iron was known as Bessemer Pig Iron.
A little later a new inventor, a Welshman, Thomas
by name, overcame the difficulty in another way, but
to explain that I must first describe the Bessemer
Converter, the special apparatus designed by
Bessemer for making his steel.
It can best be likened to a huge iron kettle with
a big spout at the top and with two projecting pins,
one on each side. These pins rest in supports, so that
it is easy to tilt the whole thing over on to its side.
This is lined with fire-clay or some suitable heat-
resisting material.
Through one of the " pins " (trunnions is their
proper name) there runs a hole, communicating to
what we might call a grating in the bottom of the
converter. To this hollow trunnion there is con-
nected the pipe from a powerful blowing engine,
so that air can be driven in at will.
To load or charge the converter it is tilted over
somewhat to one side so that molten pig iron can be
poured into it. The blast is then turned on after which
WHAT GUNS ARE MADE OF
it is raised to an upright position with the air
bubbling up from below through the iron. Thus by
being brought into close contact with air, the carbon
is burnt out of the metal until none is left. That,
however, is not desired, so, as soon as the carbon is
known to have all gone, a fresh quantity of molten
iron is added of a special kind, the amount of carbon
in which is known very exactly. Thus all the carbon
is first removed and then exactly the right amount
is added, and so the desired result is attained with
certainty.
Now Thomas's improvement was this. He dis-
covered that the converter could be lined with
certain substances which have a great attraction for
phosphorus and under those conditions any phos-
phorus which may be in the ore goes readily from
the iron into the lining, or forms, with material from
the lining, a slag which floats upon the surface of the
metal.
When the process is completed the converter is
tipped over once more and the metal, now steel, is
poured into rectangular moulds from which the
steel can be lifted after cooling in the form of ingots.
Steel produced by Bessemer 's process as improved
by Thomas is called Basic Bessemer Steel.
Incidentally Thomas, by this invention, laid the
foundation of much of the steel industry of Germany
and Belgium, for there are enormous deposits of ore
in the neighbourhood of Luxemburg which because
of the presence of phosphorus were useless until
Thomas showed how it could be dealt with.
And there is another interesting feature of this
WHAT GUNS ARE MADE OF
" basic " process. Phosphorus is a valuable fertilizer,
so that the " slag " makes a very fine chemical
manure. It is ground up into a fine powder and is
sold to farmers under the name of Thomas's Phos-
phate Powder. It owes its fertilizing virtues to the
presence of the phosphorus which it has stolen from
the molten iron.
Bessemer derived a huge fortune from his process
after he had fought and overcome his difficulties, in
addition to which he received the honour of knight-
hood and became Sir Henry Bessemer.
It will be noticed that one of the virtues of the
process is its economy in fuel. During the whole
time that the metal is in the converter, from twenty
to thirty minutes, no fuel is used to keep it hot. The
reason for that is that the carbon which is being got
rid of is acting as fuel. It is burning with the air
which is driven through, thereby generating heat.
In Bessemer' s early days, it was arranged that he
should attend a meeting of ironmasters at Birming-
ham to explain his new process. On the morning of
his lecture two eminent ironmasters were breakfasting
together in a Birmingham hotel when one exclaimed
to the other, "What do you think, there is a fellow
coming here to-day to tell us how to make steel
without fuel." To this eminent South Wales iron-
master the proposal seemed preposterous but it was
true all the same.
Although vast quantities of steel are made by the
Bessemer process there is another one of equal
importance known as the Siemens-Martin Open-hearth
process. In this the molten metal is kept in a huge
WHAT GUNS ARE MADE OF
bath practically boiling until the carbon has been
reduced to the required amount. Perhaps the most
interesting feature about it is the way in which fuel
is saved by what is called the " regenerative "
method due to that versatile genius Sir William
Siemens.
The open-hearth, as it is termed, is a huge rect-
angular chamber of firebrick with a firebrick roof, and
doors along one side just under the roof through
which the process can be watched and new materials
be added from time to time.
The fire is some way away and not underneath as
one might perhaps expect. Now if a deep coke fire
is fed with insufficient air it does not give off carbonic
acid such as usually arises from a fire, and which as
everyone knows will not burn, but a gas called
carbon monoxide which will burn very well. So the
fire-place for these furnaces is constructed in such a
manner as to produce carbon monoxide, which then
passes through a huge flue to one end of the open-
hearth. Here it meets air coming through another
flue and the two combining burst into flame over
the metal.
The hot gases resulting from this burning pass out
through a flue at the other end of the hearth to a
tall chimney which causes the necessary draught, but
on their way they pass through a chamber loosely
filled with bricks. Consequently the hot gases only
reach the open air after having given up much of
their heat to these bricks.
After that operation has been going on for a time
certain valves are operated and the gas and air then
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WHAT GUNS ARE MADE OF
come in at the other end of the hearth, travelling
through it in the opposite direction. And the air
comes through the chamber which has the hot bricks in
it, bringing back into the furnace a large quantity of
that heat which otherwise would have gone up the
chimney but which the bricks intercepted. Thus all
day long does this reversal take place at intervals, the
fresh air all the time picking up and bringing back
some of the heat which just previously had escaped
towards but not into the chimney. This arrange-
ment enables the process to compete, so far as
economy is concerned, with the Bessemer process.
At intervals the steel is tapped off from the
furnace and run into ingot-moulds, the same as with
the other process. On the whole it is regarded as
producing a slightly better steel, the operation being
under slightly better control.
However the steel is made the ingots are re-
heated and either hammered under a powerful steam
hammer or pressed in an enormous hydraulic press.
This greatly improves the quality.
The steel can then be rolled into plates, bars or
whatever form may be required.
The finer qualities of steel such as are used for
making sharp tools are made in quite another way.
Instead of being made from crude iron by taking out
the carbon, the materials are the finest qualities of
wrought iron and charcoal which are mixed together
in the correct quantities and melted in a crucible.
This cast steel is very hard, so that it will carry a
very fine, sharp edge. It is also capable of being
tempered by heating and cooling, so that the exact
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WHAT GUNS ARE MADE OF
degrees of hardness and toughness can be at-
tained.
Of recent years a special quality of steel for tools
called " high-speed " steel has been produced, mainly
by the addition to ordinary cast steel of a small
percentage of tungsten. The advantage of this is
that, within certain limits, this does not soften with
heat, and it is, I can assure you, a great invention in
war-time, when a nation is straining every nerve
to turn out guns and shells as fast as possible.
For all these things need to be turned in lathes and
if you have ever watched a metal-turning lathe at
work you will have noticed that the tool which
actually takes a shaving off the article being turned
tends to get hot. For this reason lathes are usually
fitted with pumps which pump cold soap-suds on to
the tool as it works. What you see there is the
energy employed in shaving the metal being turned
into heat in the tool. If left uncooled by the water it
would soon be red-hot. And the faster the machine
works the hotter will the tool get.
Now with the old steel a very little heat will suffice
to make it soft, when its cutting power is lost. So
with the old steel, no matter how much cooling water
you might use, there was a distinct limit to the speed
of the lathe and the speed at which the work was
finished, for if that speed were once exceeded a stop
became necessary to regrind the tool or to put in a
fresh one.
But with high-speed steel that limit is much higher,
for it can get almost red-hot before it loses its hard-
ness and consequently machines can be run and jobs
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WHAT GUNS ARE MADE OF
finished at a speed which would have been out of the
question only a few years ago. If one belligerent
knew how to make high-speed steel while the other
did not the former would have an enormous advan-
tage hi war-time.
Speaking generally, steel such as is used for tools is
called hard steel, while that made by the Bessemer
and Siemens-Martin processes is called mild steel.
Leaving out of account for the moment fancy steels
such as that just described, where other metals are
added to the mixture, the essential difference between
all the varieties of steel is simply a slight difference
in the percentage of carbon. This is so remarkable
that it is worth while to tabulate these percentages
again.
Cast iron has from 2 to 5 per cent.
Steel from one-fifth to one per cent.
Wrought iron less than one-fifth per cent.
Mild steel, which has least carbon of all the
varieties of steel and in this respect is therefore
nearest to wrought iron, is used for the same purposes
as wrought iron, such as shipbuilding, bridges and
roofs, tanks, gas-holders, etc. When the Admiralty
want a specially fast ship such as a torpedo-boat
destroyer with a hull as light as possible consistent
with strength they have it made of steel with a
slightly larger percentage of carbon so that the steel
is stronger and the vessel's frame can be made
lighter. The steel for shells, too, needs to be of a
certain strength to give the best results, so the
percentage of carbon is adjusted accordingly.
For guns themselves, again, special properties are
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WHAT GUNS ARE MADE OF
needed, and so not only is the carbon regulated to a
nicety but other things such as nickel and chromium
are added. Altogether, steel is one of the most
marvellous substances known, certainly the most
marvellous metal. Copper is just copper and no
more, zinc is just zinc, and the same with lead, but
iron (which really includes steel) can be adapted to
so many purposes, can be endowed at will with so
many different properties, that without doubt iron,
common, plentiful iron, is the king of all the metals.
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CHAPTER VIII
MORE ABOUT GUNS
Al has been remarked elsewhere, some of the
guns used by the soldiers in land warfare
are very different from those used in the
navy. The latter, being carried on the ships to which
they belong, can be of those proportions which best
suit their purpose. Consequently they are usually
very long compared with their diameter.
The field guns used by the Royal Field Artillery
are shorter in proportion to their calibre than are the
big naval guns. Otherwise they would be far too
long to handle in the field. They are mounted on
carriages drawn by horses, and are so handy that they
can go anywhere where infantry can go and can travel
just as fast. It takes a very short time to get them
ready for action, too, so that they can accompany
infantry quite freely, neither arm impeding the
movements of the other. The Horse Artillery, again,
whose guns are even lighter still, can accompany
cavalry, travelling as fast and coming into action
almost as quickly as the troopers themselves.
The famous French " seventy-fives " (meaning
75 millimetres calibre) which played such a great
part in the war, are field guns intended to move
rapidly and to operate with infantry.
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Both these types of gun were used by the
British in South Africa, as also were some field
howitzers, a type of gun to which further reference
will be made later. But the Boers taught the world
something new as to the possibilities of moving
heavy guns quickly. Perhaps the reason for this
was that they, being something of the nature of
amateurs in the art of warfare, were less under the
influence of tradition. Anyway, they surprised the
Britisl by the quick way in which they moved heavy
guns, ometimes into quite difficult positions, over
rough ground and up steep hills. These heavy guns
of theirs were called by the British soldiers " Long
Toms."
But the British were quick to respond, particu-
larly the ever-resourceful navy. When the war
broke out there were, in the neighbourhood of Dur-
ban, a number of warships which had as part of their
own armament some of those guns which afterwards
became famous as " 4-7's," that being the diameter
of the bore in inches. They were of the long shape
usual in naval guns, and it is easy to see that they
were much heavier than the field guns of 3 inches
or so in diameter.
Captain Scott (now Admiral Sir Percy Scott) saw
that these would be useful, so he quickly designed
some carriages for them, got these made in the rail-
way workshops at Durban, and in a few hours was
rushing them up to Ladysmith. It was these guns
very largely which enabled that town to hold out
for so long, until, in fact, it was triumphantly re-
lieved.
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Thus the effect of the Boer war was to show that
much heavier weapons could be manipulated in the
field than had been considered possible before. The
Great War which followed but a few years later
carried on this same lesson, for one of the great sur-
prises with which the Allies were confronted in the
early days of the conflict was the inexplicable fall of
fortresses which till then had been deemed almost
impregnable.
Liege, Namur, Maubeuge and, finally, Antwerp,
all fell to a wonderful gun of enormous dimensions
which the Austrians had produced from up their
sleeve, so to speak. Like conjurers they had kept
them secret until the last moment.
These weapons which made history so fast were of
the kind called howitzers, a name mentioned just
now. It should be explained here that gunners talk
of guns and howitzers as if the latter were not guns ;
but that is only a convenient habit which has grown
up, for the latter are unquestionably guns. The
distinction is, however, so convenient that we may
well adopt it ourselves for the rest of this chapter.
Repeated references have been made already to
the question of the length of guns, and it has been
pointed out that to get high velocity, great range
and vigorous hitting power a gun needs to be as long
as possible. On ships this is only limited by the
strength of the steel of which the gun is made, for
beyond a certain length the gun bends of its own
weight. Ashore, however, the difficulties of transport
impose a further limitation in most cases, although
the famous 4-7, like many other naval guns, has a
MORE ABOUT GUNS
length of 50 calibres, and the guns of small calibre
do approximate somewhat to the proportions of the
naval guns, since even then their length comes within
manageable limits.
Modern warfare, however, requires the use of larger
shells containing larger charges of explosives, and to
fire these requires guns of greater calibre. We hear
of shells of as great a diameter as 16 inches being
thrown into the Belgian fortresses and of course
nothing smaller than a 16-inch gun could do that.
Now a 16-inch gun, if made to the naval proportions
of 50 calibres or even 45 calibres, would mean a length
of at least 60 to 70 feet. It would also mean a
weight exceeding 100 tons, for the 12 -inch naval gun
of 50 calibres weighs about 70 tons. And it is easy
to see that such a gun would be very difficult to move
on the field of battle. Indeed, it would be almost
useless because of the time it would take to get it into
position and to construct the foundations which it
would need. If the Austrians had only had such as
those the Belgians would have had plenty of time to
prepare for them at Antwerp, whereas it was the
quickness with which they brought up their heavy
guns that astonished everyone and took their oppo-
nents by surprise.
The secret of this astonishing performance lies in
the fact that they were not guns at all but howitzers,
which instead of being long, slender tubes are short,
fat ones, and that involves a different idea in gunnery
altogether. The " gun " fires at an object. The
howitzer fires its shell upwards with the purpose of
dropping it upon the object.
MORE ABOUT GUNS
The difference between the two is well illustrated
by the methods of practising with them. In learning
to work a gun the gunners fire at a vertical target
just as those of you who practise shooting at a minia-
ture range fire at a target of paper placed vertically
against a wall. The target for howitzer practice, on
the other hand, is a square marked out on the level
ground, and the object of the gunners is to see how
great a proportion of a given number of shots they
can drop inside that square.
Of course, being so much shorter the howitzers
cannot throw a shell so far or at such a high velocity
as the naval guns, but that can to a certain extent
be compensated for by using a higher explosive for
the propellant. That, however, involves greater
stresses in the tube when firing takes place and also
calls for stronger foundations in order that the aim
may be steady.
A great part, too, of the velocity of a naval shell
is required for the penetration of the armour, whereas
against forts or earthworks it is sufficient if the shell
" gets there."
Moreover, generally speaking, it is possible to get
much nearer to a fortress or entrenched position for
the purpose of attacking it than it is to an enemy
ship on the sea. Except for the occasional help of a
mist there is no " cover " to be obtained at sea,
while on land the ground must be very flat indeed if
there is no low hill or undulation behind which a gun
can be set up unnoticed.
The Austrians cherish a piece of steelwork from
one of the forts of Antwerp which they smashed with
MORE ABOUT GUNS
a shell from one of their big howitzers at a range of
seven miles. They evidently were able to get their
big howitzers within that comparatively short dis-
tance of the Antwerp fortifications without being
molested.
In this connection one often hears the word mortar
used, and just a reference to that will be appropriate
here. Many years ago short guns which threw their
balls very high were in use, and because of their
resemblance to the mortar which is used for pounding
up things with the aid of a pestle these were termed
mortars. Later a man named Howitzer introduced
a type of gun which was something of a compromise
between the long thin gun and the short stubby
mortar. As time has gone on, however, the mortars
have grown in length while the howitzers have
shortened, until to-day the two names are used almost
indiscriminately to denote the same thing. Hence
the giant howitzers of the Austrians are often spoken
of as the " Skoda " mortars, Skoda being the name
of the factory where they were made.
At one .time many people wondered why the
Germans did not put some of these huge mortars on
their battleships : many thought that they would
do so, and that by that means they would demolish
our navy as they had already smashed the Belgian
forts. The reason they did not is, no doubt, the very
simple one, that our naval guns would have probably
sunk their ships before the howitzers could have
reached ours, because if they had attempted to make
up for the shortness of the weapons by using higher
explosives, these mortars would, there is little doubt,
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MORE ABOUT GUNS
have knocked to pieces the ships on which they were
mounted.
The old-fashioned fortress, suddenly made " out-of-
date " by the Skoda mortars, was usually armed with
guns of the naval type. Sea-coast forts are always
so armed. Nowadays, however, the inland fortress
takes the form of a labyrinth of trenches and under-
ground passages, combined with deeply excavated
chambers known as dug-outs, and these do not fitly
accommodate large guns at all. The guns are placed
well back behind the trenches sheltered behind hills
or woods, over which they hurl their shells. The
chief defenders of the actual trench are the machine
gun, which is little more than an automatic rifle on
a stand, and the trench mortar.
We are now in a position to sum up broadly the
features of modern artillery. There is first the
naval gun, the ideal gun, long and of great range,
able to send forth its shells with great velocity.
This gun appears again in the sea-coast forts, where
the conditions are very much those which obtain
on a ship and where the attacking party is of neces-
sity a ship.
In the field we have the field and horse artillery,
which we may regard as the naval gun modified
somewhat in order to make it easy to move about,
so that it can accompany troops and support the
operations of both infantry and cavalry. These light
guns are supported by the field howitzers, which
are also light and easily handled, and the guns of
the 4-7 type, originally naval guns but now mounted
on wheels and possessing a certain amount of
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mobility, not equalling the field guns it is true, but
still very serviceable in a campaign.
Then we have the howitzers of various sizes which
have rendered the old-fashioned steel and concrete
forts useless, and which are the chief weapons used
in the modern trench warfare. It is these which
blow in the walls of the trenches and dug-outs,
shatter the barbed-wire entanglements and render
it possible for the infantry to attack an entrenched
position.
Finally, we have the machine guns, each of which
is equivalent to a considerable number of riflemen
and which, with the trench mortars, form the chief
defences of the actual trench itself. Of course these
are only useful against attacks by infantry : they
cannot in any way cope with the heavy artillery.
That has to be dealt with by the opposing artillery
posted away back behind the trenches.
And now let us take a rather more close look at
some of these weapons. Essentially each one is
a steel tube. It may be a single tube or it may be
several onej outside another. It may even have a
layer of wire between two tubes as many naval guns
have. It is invariably (one small exception will be
mentioned later) loaded at the breech or rear end
and not through the muzzle as used to be the custom.
For this purpose it needs a breech-block or door,
which can be opened to put in the shell and explosive,
and which can then be closed tightly so that it will
not be driven out or burst open when the explosion
takes place and also shall be gas tight so as not to
let any of the force of the explosion escape.
MORE ABOUT GUNS
Then the gun must be mounted upon a carriage
so that it can be quickly moved about. The lighter
forms of artillery are fired when upon the same
carriage upon which they travel. In years gone
by the whole thing, carriage as well as gun, used to
run back when the gun was fired, which was a great
nuisance since it had to be got back into position
again after each shot. To obviate this the gun is
now mounted upon a slide, and it is the slide which
is fitted to the carriage. Thus the gun can slide back
without the carriage moving at all. The latter is
made very strong, and shoes are provided at the end
of chains which go under the wheels just like the
" drag " which coaches and heavy carts have for use
going down hills. There is also a part like a spade
which can be driven down into the ground so that,
what with the shoes and the spade, the carriage is
fixed very firmly.
The gun is kept at the front part of the slide by
means of a powerful spring, which is compressed
when the gun is fired but which, as the force of the
recoil is spent, pushes the gun back to its original
position once more. The spring is often reinforced
by a cylinder and a piston with compressed ah* or
water behind it, acting after the manner of those
door checks with which we are all familiar, its func-
tion being to steady the motion of the gun and to let
it go gently back to its place without slamming,
just as the door check prevents a door from slamming.
By this means the gun is returned automatically
after each shot to practically the same position which
it occupied before, so that it does not need re-aiming
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each time, but only a slight readjustment if even
that. The result of this is that such a gun can be
fired very rapidly. In fact, it can be fired just as
fast as the gunners can keep on reloading it.
The big Skoda mortars owed their mobility to
the clever way in which they were constructed. The
gun tube itself, the support for it or mounting, and
the steel foundation were each fitted to a special
motor-driven trolley. The steel foundation was
dumped down on the ground, which of course was
prepared for it in advance, then the mounting was
run right on to it so that it simply needed bolting
down and finally the tube was hoisted by specially
prepared appliances into its place. It is said that
the whole operation occupied less than an hour.
For firing, these mortars of course are pointed at
a very high angle, almost like an astronomical tele-
scope. No doubt the gunners have many jokes about
" shooting the moon " and so on, for that is just
what they seem to be attempting. For loading,
however, they are lowered into a horizontal posi-
tion : the shell comes up on a small hand-truck, is
raised by a specially designed jack until it is level
with the breech, and is then pushed into its place.
The breech is then closed, the tube re-elevated, and
all is ready for firing.
Between these two forms of gun, the field gun on
its light carriage, which not only bears it from place
to place but forms its support while in action, and
the great mortar carried in parts on specially made
trolleys, there are now an enormous variety of guns
and mortars adapted for the various purposes which
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experience in the Great War revealed. Artillery
suffered many changes in the light of the South
African campaign and of the Russo-Japanese war,
but of far more importance have been the lessons
learnt in Northern France and on the plains of
Poland. To some extent these lessons have been
learnt and profited by during the actual war, but
there is no doubt that as men have time to think
over them in the years of peace which are ahead
many more developments will take place. Unless,
that is, we are on the threshold of that happy time
when guns and fighting material of all sorts will be
looked upon as the relics of a bad and ruinous time
now happily past.
In conclusion, a passing reference must be made
to the trench mortars and similar contrivances which
have arisen as the result of the prolonged spell of
trench warfare which no one had ever contemplated.
These are in effect very short range mortars or
howitzers, specially intended for throwing bombs
from trench to trench. Some are simply the larger
mortars on a small scale, but one has decidedly original
features.
This consists of a short light mortar into which
the bombs are slipped through the muzzle, thus
reverting to the old method of loading. The pro-
pellant is combined with the bomb and there is a
percussion cap which fires it as soon as it strikes the
bottom of the tube. Thus the operation is just
about as simple as it can be : the man merely places
the bomb in the upturned muzzle and lets it slide
down. An instant later, up it comes again, to go
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sailing through the air into the trench of the enemy
a hundred yards away.
One must not conclude this chapter, however,
without a reference to those useful weapons which
are known among the soldiers as " Archibalds " and
officially as anti-aircraft guns. These are perhaps
the most familiar guns of all to the general public,
since they were installed in many places in Britain
for the purpose of dealing with the Zeppelins. No
doubt not a few of my readers have had the experi-
ence of being awakened from their beauty sleep by
the cracking of the anti-aircraft guns and have seen
their shells bursting like squibs in the air.
They are fairly long guns, not unlike field guns,
but they are mounted upon special supports which
enable them to be pointed at any angle so that they
can fire right up into the sky. The sights, also, are
somewhat different, being fitted with prisms, or
reflectors, so that the gunners can look along the
sights and align the gun upon an object overhead
without lying on their backs.
Much more could be said on this subject, but
national interests forbid, so with this general review
of modern artillery we must pass to another subject.
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CHAPTER IX
THE GUNS THEY USE IN THE NAVY
BOTH the great English-speaking nations are
immensely proud of their navies. They can,
on occasion, produce soldiers by the million
of the very highest and most efficient type, but they
never feel quite that pride and patriotic fervour over
their soldiers that they do over their ships of war and
their sailors.
The guns, therefore, with which the ships are armed,
always form a subject of great interest, especially
those large ones which constitute the armament of
the Dreadnought battleships and battle-cruisers.
Let us first consider what is required in a naval
gun, for it must be remembered that the naval and
military weapons are different in some respects.
Experience at the Dardanelles showed that even the
guns of the Queen Elizabeth, the largest and most
powerful then known, fresh from the finest factories,
were not particularly successful against the Turkish
forts. The Germans, too, set up what was probably
a naval gun and occasionally dropped shells into
Dunkirk with it at a range of twenty miles or so, but
without causing much harm, and the fact that they
only did it occasionally and then abandoned it
GUNS THEY USE IN THE NAVY
altogether seems to indicate that in their opinion
they were not doing much good with it.
It must not be assumed from this that naval guns
are bad guns or poor guns, however, but simply that
they are made for a special purpose for which they
are highly efficient, from which it follows almost as a
natural consequence that they are somewhat less
efficient when used for some other purpose. Their
purpose is to pierce the hard steel armour with which
warships are protected and then to explode in the
enemy's interior, whereas in modern warfare the
greatest military guns are chiefly required to blow a
big hole in the ground or to shatter a block of
concrete. In both cases the ultimate object is to
carry a quantity of explosive into the enemy's
territory and there explode it, but whereas the land
gun has simply to do that and no more, the naval gun
has to pierce thick armour-plate as well.
And just think what that means. Many large ships
have their vital parts protected by armour-plates
twelve inches thick. Moreover, the armour-plates
are made of very special steel, the finest that can be
invented for the purpose. Vast sums of money have
been expended in experimenting to find out just the
best sort of steel for resisting penetration by shells.
Some time ago I saw several pieces of armour-plate
which had been used in one of these tests. They had
been set up under conditions as nearly as pbssible the
same as those obtaining on the side of a ship and then
they had been fired at from varying distances, the
effects of the various shots being carefully recorded.
And that is only one experiment out of tens of
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GUNS THEY USE IN THE NAVY
thousands which have been tried again and again,
while the steel manufacturers are always trying to
improve and again improve the shell-resisting
properties of their steel. Thus, we see, the presence
of the steel armour which has to be perforated before
the shell can do its work makes the task set before the
naval gun somewhat different from that which con-
fronts its military brother.
These considerations result in the naval gun
needing to have as flat a trajectory as possible and
its projectiles the highest possible speed.
Now trajectory, it may be useful to explain, is the
technical term employed to denote the course of a
projectile, which is always more or less curved.
Let us imagine that we see a gun, pointed in a
perfectly horizontal direction, and let us also imagine
that by some miracle we have got rid of the force of
gravity and also that there is no air. Under those
conditions the shot from the gun would go perfectly
straight and with undiminished velocity for ever and
ever. Then let us imagine that the air comes into
being. The effect of that is to act as a brake which
gradually slows the shell down until finally it stops it.
Theoretically, perhaps, it would never quite stop it,
but for all practical purposes it would.
Again, let us suppose that while the air is absent
the force of gravity comes into play, what effect will
that have ? It will gradually pull the shell down-
wards out of its horizontal course, making it describe
a beautiful curve.
But, someone may think, does not a rapidly-
moving body remain to some extent unaffected by
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GUNS THEY USE IN THE NAVY
gravity ? Not at all : it falls just the same and just
as quickly as if it were falling straight down.
If our imaginary horizontal gun were set at a
height of sixteen feet and a shell were just pushed out
of it so that it fell straight down the shell would
touch the ground in one second. If the ground were
perfectly flat and the shell were fired so that it
reached a point half a mile away in one second it
would strike the ground exactly half a mile away.
You see, the horizontal motion due to the explosion
in the gun and the downward motion due to gravity
go on simultaneously and the two combined produce
the curve.
To make this quite clear, let us imagine two guns
precisely alike side by side and both pointed perfectly
horizontally. From one the shell is just pushed out :
from the other it is fired at the highest velocity
attainable : both those shells will fall sixteen feet or
a shade more in one second, and if the ground were
perfectly level both would strike the ground at the
same moment although a great distance apart.
Clearly, then, the faster the shell is travelling the
more nearly horizontally will it move, for it will have
less time in which to fall, and the slower the more
curved will be its path, from which we see that the
air by reducing the velocity causes the curve to
become steeper and steeper as the shell proceeds.
If, then, our gun is placed low down, as it must be
on a ship, to get the longest range we must point it
more or less upwards because otherwise the shell
will fall into the water before it has reached its target.
When we do that we complicate matters somewhat, for
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GUNS THEY USE IN THE NAVY
gravity tends to reduce the velocity while the shell
is rising and to add to it again while it is falling.
We need not go too deeply into that, however, so long
as we realize that, whatever the conditions may be,
the shell in actual use has to follow a curved course,
first rising and then falling.
The really important part about a shell's journey
is the end. So long as it hits it really does not matter
what it does on the way, and if it misses it is equally
immaterial. The reason why we need to bother
about the first part of the trip is because upon it
depends the final result. Whatever the trajectory
may be we see that the shell must necessarily arrive
in a slanting direction. And the more steeply
slanting that direction is the less likely is the target to
be hit.
If the shell went straight it would only be neces-
sary to point the gun in the right direction and the
object would be hit no matter how far away it might
be. The more curved the course is, the more likely
the shell is to fall either too near or too far, in the
one case dropping into the water, in the other passing
clear over the opposing ship.
Let us look at it another way. Suppose the vital
parts of a ship rise 20 feet out of the water and
the shell arrives at such an angle that it falls
20 feet in 100 yards : then, if the ship be within
a certain zone 100 yards wide it will be hit in a
vital spot. If it be nearer the shell will pass over,
if it be further the shell will fall into the water. That
100 yards is what is called the " danger zone." If
the shell is falling less steeply, say, 20 feet in 200
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GUNS THEY USE IN THE NAVY
yards, then the danger zone is increased to 200 yards
and so on, which gives us the rule that the flatter the
trajectory, or the more nearly straight the course of
the shell the greater is the danger zone and the more
likely is the enemy ship to be hit.
We have established two facts, therefore, first,
that the trajectory must be as flat as possible and,
second, that to make it flat the velocity must be high.
We can also see another reason for high velocity,
namely, to give penetrating power.
To obtain a high velocity the gun must be long, and
consequently naval guns are always long, a fact which
is very noticeable in the photographs of warships.
The reason for this is quite obvious after a little
thought. You could not throw a cricket ball very
far if you could only move your hand through a
distance of one foot. To get the best result you
instinctively reach as far back as ever you can and
then reach forward as far as you are able, so that the
ball shall have as long a journey as possible in your
hand. Perhaps you do not know it but all the time
you are moving your hand with the ball in it you are
putting energy into that ball, which energy carries it
along after you have let go of it. And it is just the
same with the shell in the gun. So long as it is in the
gun energy is being added to it but as soon as it
leaves the muzzle that ceases. After that it has to
pursue its own way under the influence of the
energy which has been imparted to it.
The powder which is employed as the propellant or
driving power is of such a nature and so adjusted as
to quantity that as far as possible it shall give a com-
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paratively slow steady push rather than a sudden
shock, so as to make full use of the gun's length, the
expanding gases following up the shell as it goes
forward and keeping a constant push upon it.
On the other hand, a gun can be too long, for no
steel is infinitely strong and stiff, so that beyond a
certain limit the muzzle of the gun would be likely to
droop slightly of its own weight and so make the
shooting inaccurate. The limit seems to be about
50 calibres or, in other words, fifty times the diameter
of the bore.
For a considerable time the standard big gun of
the British Navy was the 12 -inch, that being the
calibre or diameter of the bore. The famous Dread-
nought had guns of that calibre and so had her
immediate successors.
The 12-inch gun of fifty calibres weighs 69 tons
and fires a projectile weighing 850 Ibs. which it hurls
from its muzzle at a velocity of about 3000 feet
per second.
More recently the size has grown to 18 J, 14 and even
as great as 15 inches calibre, but we may for the
moment take the 12-inch gun as typical of all these
large guns and have a look at its construction.
It is made of a special kind of steel known as
nickel-chrome gun steel, formed by adding certain
proportions of the two rare metals nickel and
chromium to the mixture of iron and carbon which
we ordinarily call steel. The metal is made after the
manner described in another chapter and is cast into
the form of suitably-sized ingots which are afterwards
squeezed in enormous hydraulic presses into the
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GUNS THEY USE IN THE NAVY
rough shape required. Besides giving the metal the
desired form this action has the effect of improving
its quality. Since a gun is necessarily a tube it may
be wondered why the steel is not cast straight away
into that shape instead of into a solid block and the
reason why that is not done is very interesting.
It is found that any impurities in the metal and it
is impossible to make it without some impurities
collect in that part which cools last and obviously
that part of a block which cools last is the centre.
Thus the impurities gather together hi the centre
of the mass whence they are removed when that centre
is cut away, whereas if the first casting were a tube
they would collect in a part which would remain in
the finished gun.
The ingot, then, is cast and pressed roughly to
shape. Then it is put into a lathe where it is turned
on the outside and a hole bored right through the
centre.
But that is by no means all of the troubles through
which this piece of steel has to pass. It undergoes a
very stringent heat treatment, being alternately
heated in a furnace to some precise temperature and
then plunged into oil, whereby the exact degree of
hardness required is attained.
Moreover, this is only one of the tubes which go to
make up the gun, which is a composite structure of
four tubes placed one over another with a layer of
tightly wound wire as well.
First, there is the innermost tube, the whole length
of the gun, then a second one outside that, usually
made in two halves. Both are carefully made to fit,
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GUNS THEY USE IN THE NAVY
and then the outer is expanded by heat to enable it
to be slidden over the inner one, after which on
cooling it contracts and fits tightly. Outside this
second tube is wound the wire, or more strictly
speaking tape, for it is a quarter of an inch wide and
a sixteenth thick. It is so strong that a single strand
of it could sustain a ton and a half. It is carefully
wound on ; first several layers running the whole
length of the gun and then extra layers where the
greatest stresses come, that is to say, near the breech,
for that has to withstand the initial shock of the
explosion. Altogether about 130 miles of wire go on
a single gun.
The advantages of this form of construction are
many. For one thing, a wire or strip can be examined
throughout its whole length and any defect is sure to
be found, whereas in a solid piece of steel, no matter
how carefully it may be made, there may lurk hidden
defects. Moreover, if a solid tube develops a crack
anywhere it is liable to spread, whereas a few strands
of wire may be broken without in any way affecting
the rest. It has been found that even if a shell burst
while inside one of these guns no harm is done to the
men in the turret where it stands, a thing which
cannot be said for guns composed entirely of tubes,
so that the merit rests with the wire. A third
advantage is that the wire can be wound on to the
tube beneath it at precisely that tension which is
calculated to give the best result, whereas in shrink-
ing one tube on to another this cannot always be
attained.
Over the wire there come two more tubes not
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GUNS THEY USE IN THE NAVY
running the whole length but meeting and overlapping
somewhat near the middle, so that at one point there
are actually four concentric tubes besides the wire.
At the rear end a kind of cap called the breech-
piece covers over the ends of all the tubes, itself
having a central hole into which fits the breech-
block, one of the triumphs of modern engineering, of
which more in a moment.
While we have in mind the wire-wound form of
construction it is interesting to note that something
similar but in a crude form was practised sixty years
or more ago. The guns of that era were some of
them even of cast iron while the more refined con-
sisted of a steel tube strengthened with coils of
wrought iron. This iron was first rolled into flat bars,
then it was made hot, and wound on spirally round
an iron bar the same size as the tube. A little
hammering converted this spiral into a tube which
was then fitted round the steel tube. Thus, although
very different there is still a distinct resemblance
between this old method and the up-to-date wire-
wound weapon.
The manufacture of guns, it may be remarked,
owes more to one man than to any other, namely,
Mons. Gustave Canet, a French engineer who, having
fought in the Franco-German War, decided to
devote his engineering talents to developing the
artillery of his native land. He spent many years in
England but later established works at Havre for
the manufacture of guns upon improved methods,
finally merging his interests into those of the great
French armament firm of Schneider of Creusot.
i 129
GUNS THEY USE IN THE NAVY
By French and English artillerists at all events the
name of Canet is regarded with reverence.
But to get back to our naval gun. It will be clear
that operations such as have been described, involving
the handling of great tubes fifty feet or more in
length, heating them as required, dipping them in
oil while hot and so on, can only be carried out
at works specially designed for the purpose.
The furnaces where the tubes are heated are well-
like formations in the ground, deep enough to take
the tube vertically. To lift them in, and out there
have to be tall travelling cranes capable of catching
the tube by its upper end and lifting it right out of
the furnace so that its lower end clears the ground.
To accomplish this with a little to spare the cranes
need to be seventy feet or so high.
Then there are deep pits full of oil so that a tube
can be heated in a furnace, drawn out by a crane
and quickly dropped into the adjacent oil bath.
Likewise there have to be pits of a third kind wherein
a cold tube can be set up while a hot one is dropped
over it for the purpose of shrinking the latter on.
Then, of course, there have to be lathes of gigantic
dimensions capable of taking a length of nearly
sixty feet and of swinging an object weighing anything
up to fifty tons. But of those machines we can only
pause to make mention, for we must pass on to the
breech-block, in some ways the most interesting part
of the gun.
When it was first suggested to leave the back end
of the gun open so that the powder and projectiles
could be put in that way instead of through the
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GUNS THEY USE IN THE NAVY
muzzle, people at once foresaw how much would
depend upon the arrangements for stopping up the
hole while the gun was fired. For, of course, the
force of the explosion is exerted equally in all
directions, backward just as much as forward, so
that unless very securely fixed the stopper closing
the breech would be liable to become a projectile
travelling in the wrong direction. To fix such a
thing securely enough to avoid accidents would
surely take up too much time and so largely
neutralize any advantage arising from its use. These
fears were, indeed, to some extent justified by
accidents which actually occurred with the early
examples of breech-loading guns, and for that
reason our own authorities for a time looked askance
at breech-loaders.
Now let us take a look at the breech-block of the
12-inch naval gun of to-day, which never blows out,
not even when 350 Ibs. of cordite go off just the
other side of it. The explosion hurls an 850-pound
shell at the rate of 3000 feet per second but it never
stirs the breech-block. Yet it can be opened and
closed so quickly, including the necessary fastening-up
after closing, that shots can be fired from the gun
at the rate of one every fifteen seconds.
The breech-block partakes of the nature of a plug
and also of a door. It swings upon hinges like the
latter but its shape more resembles the former.
If we want to make such a thing very secure we
usually make it in the form of a screw with many
threads, but that entails turning it round many times
and that takes time. Given plenty of time to screw
GUNS THEY USE IN THE NAVY
the breech-block into its place and there would never
have been any anxiety as to the possibility of its
blowing out, but there is not time. The problem,
therefore, was to get the strength of a screw combined
with quickness of action.
This dilemma is avoided in the following simple
manner. The breech-block is given a screw thread
on its exterior surface, and the hole in the breech-
piece is given a similar screw-thread on its inner sur-
face, just as if the one were to be laboriously screwed
into the other after the manner of an ordinary screw in
machinery. Then four grooves are cut right across
the threads on the block and similarly on the breech-
piece, so that at four different places there is no thread
left. In other words, instead of the thread running
round and round continuously, each turn is divided
up into four sections with sections of plain un-
threaded metal in between. Thus in a certain
position the block can be pushed into the hole
without any threads engaging at all, for each strip
of threaded block passes over an unthreaded strip
in the hole and vice versa, in other words, the threads
on the one part miss those on the other part. Yet an
eighth of a turn serves to make all the threads
engage and the thing is held almost as securely as if
it were just an ordinary screw with threads its whole
length.
The block is carried upon a hinged arm so that
although it can be turned in this manner it can also
be swung back freely when necessary.
Combined with the breech-block is a pneumatic
contrivance which blows a powerful jet of air through
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GUNS THEY USE IN THE NAVY
the gun every time the breech is opened, thereby
cleaning away the effects of the last explosion.
Each of these great guns is mounted upon a slide
so that when it is fired it can slide back, thereby
exhausting the effect of the recoil, yet can be
returned instantly to its original position. Indeed,
this return is brought about quite automatically by
the agency of springs, compressed air and hydraulic
power. Thus the gun fires, slides back, returns and
is at once ready for the next shot.
It is trained, or pointed in a horizontal plane, by
turning the turret in which it stands but the correct
elevation is gained by the use of telescopic sights.
The principle of these sights is very simple.
Imagine a graduated circle fixed to the side of the
gun. Pivoted at the centre of the circle is a small
telescope. The telescope can be turned round to any
angle upon the circle and it can then be clamped at
that particular angle.
The range having been given to the officer in
command of the gun from the range-finding station
on another part of the ship, the telescope is set to the
correct angle. Then the gun is elevated or depressed
until the ship being aimed at is precisely in the
centre of the field of view of the telescope, in other
words, until the telescope is pointing exactly at
the ship. Then the gun is fired.
The effect, therefore, is this. The telescope always
points (while the gun is being fired) at the object
aimed at, but the gun is pointed upwards at a certain
angle, which angle depends upon how the telescope
is set upon the divided circle. Thus the setting of
GUNS THEY USE IN THE NAVY
the telescope for a given range produces the correct
upward tilt of the gun for that range.
The breech-block carries a trigger and hammer
arrangement whereby the firing can be done and also
an electrical arrangement so that an electric spark
can be employed. Both these firing contrivances are
so made that they cannot be operated until the
breech-block has been inserted and made secure.
Thus a premature explosion is guarded against.
CHAPTER X
SHELLS AND HOW THEY ARE MADE
MODERN warfare seems to resolve itself
very largely into a question of which side
can procure the most shells. During the
great war there was a time when the British and
their allies were hard pressed because they had not
sufficient shells. The enemy had in that matter
stolen a march upon them and had during the winter,
when military activity is at its minimum, rapidly
produced large supplies of high-explosive shells.
Discovering their lack the British set about
remedying it in true British fashion. It is quite
characteristic of this strange people to let the enemy
get ahead at the commencement, after which they
pull themselves together and put on a spurt, so to
speak, and after that the enemy had better prepare
for the worst, for defeat is only a question of
time. So, finding themselves short of shells, they
set to and dotted the whole country in an in-
credibly short time with huge factories entirely
devoted to making shells. Older factories also
were adapted to the same purpose. Places in-
tended and normally used for the manufacture
of the most peaceable things ploughs, gramo-
phones and piano parts for example were soon
SHELLS AND HOW THEY ARE MADE
turning out shells or parts thereof by the thousand.
Electric - light works, waterworks, cotton mills,
technical schools, all sorts of places where, for
doing their own repairs or for some similar reason,
there happened to be a lathe or two, all these were
organized and in a few weeks they too were working
night and day " something to do with shells."
Meanwhile other factories were springing up for
the purpose of making explosives while others
again were erected for producing the acids and other
chemicals necessary for the explosive works ; and yet
another kind of works, the filling factories, came into
being as if by magic and thousands of girls flocked
from far and near to these places, there to fill the
shells with the explosives.
Even the soldiers did not realize a few years ago
how important the supply of shells was going to be.
The rifle has fallen from its old place of importance
while the gun and the shell have risen to the first
place.
What, then, is a shell ? It is what its name
implies, a case covering something else, just as the
shell of a fish covers its owner. It is a hollow cylinder
of steel with certain things inside it. Its chief
function is to hold these other things and to be shot
out of a gun carrying them with it to their destina-
tion. You want to cause an explosion in an enemy's
ship. You cannot get near enough to put the
explosives there by hand, for he will not let you, so
you put them into a steel shell and then hurl the
whole thing at him out of a gun.
In the attempt to prevent your doing him any harm
136
BOMB THROWING.
One of the most striking things about the v
thrown by hand. This officer hurled bombs
continuously.
was the re-invention of the bomb
the enemy for twenty-four hours
SHELLS AND HOW THEY ARE MADE
by thus throwing boxes of explosives at him, the
enemy clothes the sides of his most valuable and
important ships with thick steel plates, wherefore
you have to make your shell strong and tough so
that it shall not splinter against the armour but shall
on the contrary bore its way through, finally explod-
ing in the interior of the ship.
If it is not a ship that you are attacking but, say, an
earthwork or an arrangement of trenches, then you
do not need to penetrate steel armour and your shell
can be thinner and of lighter construction. It still
needs to be strong, however, for it has another
function besides simply carrying the explosive. It
must hold the force of the explosion in for a moment
while it gathers force so that when the hour comes
the pent-up energy may strike all round with the
utmost violence. Even the most powerful explosives
are comparatively feeble if they go off in the open.
By holding them in check for a moment and then
letting their force loose suddenly you get a much
more forceful blow.
Shells which contain only an explosive are called
common shells or high-explosive shells. Shrapnel
shells constitute another type in which the force of
the explosion is simply employed to release a number
of round bullets, which strike mainly because of the
velocity which they derive from the original motion
of the shell. These are above all things man-killing
shells, for their result is akin to a volley of bullets at
close range.
We can thus sum up the chief types of shell as
follows : the naval shell which has to be capable of
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SHELLS AND HOW THEY ARE MADE
penetrating armour : the high-explosive shell which
must be able to break up earthworks and blow down
the walls of trenches : and the shrapnel shell which
scatters a shower of bullets and is most useful in
attacks upon bodies of men rather than upon material
structures.
Some shells have their propellent explosive com-
bined with them just as the familiar rifle cartridge
contains the propellant combined with the bullet.
In the larger sizes, however, it is much more con-
venient to have the propellant in a separate cartridge,
which can be handled separately and loaded into the
gun separately.
As has been already explained, the propellant is a
" powder " which gives a steady push rather than a
destructive blow : moreover, it is practically smoke-
less, so as not to " give away " the position of the
gun to the enemy. The " high explosive," however,
shatters and usually makes a dense smoke, so that
the observers can see where it fell and report to the
gunners whether or not they have got the range.
Soldiers' letters have told us of the " black Marias "
and " coal boxes " used by the Germans, those terms
being simply soldiers' nick-names arising no doubt
from the fact that certain particular shells are filled
with " tri-nitro-toluene " which gives a black smoke.
Clearly, smoke, which is most objectionable in the
propellant, is a positive advantage in the bursting
charge.
And now let us take a glimpse at the manufacture
of one of these terrible missiles. An ingot of shell-
steel is first cast as described in an earlier chapter,
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SHELLS AND HOW THEY ARE MADE
Since impurities are apt to rise, while the metal is
liquid, the top of the ingot is always cut off and
discarded. This waste material is used for many
other purposes, in which a chance flaw would not be
a serious matter, under the title of " shell-discard "
steel.
The lower part is then heated and passed through
a rolling mill, a machine very similar in principle to
the domestic mangle, the rollers being of iron with
suitable grooves cut in them. A few passages
through this machine transforms the ingot into a
thick round bar. This is then sawn into short pieces
called billets, each of which is the right size to form a
shell. Again heated, a powerful press drives a
pointed bar through the softened steel, thereby
converting the short billet into a rough tube. Another
press then slightly closes in one end, making it
resemble a bottle without a bottom and with the
neck broken off.
The rough forging is then ready to be machined, an
operation which is performed in a lathe. The outside
is made perfectly round and smooth and of precisely
the right size. The inside is also bored out to the
correct diameter and finished off to an exceeding
smoothness so as to avoid the possibility of any
rough places irritating the explosive which in due
time will be filled into it. For the same reason, the
inside, when finished, is varnished in a certain way
and with a certain varnish. The formation of this
varnish is one of those little thought of but highly
important services which alcohol renders to us, as
mentioned elsewhere.
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SHELLS AND HOW THEY ARE MADE
The smaller end (that which has already been
partially squeezed in) is bored out and screwed for
the reception of the nose-bush, while the other end is
recessed for the reception of the plate which forms
the bottom.
Most of these operations have to be very accurately
carried out and, to ensure that that is so, gauges are
continually employed to check the work. These
gauges are based upon a very simple principle, known
as the " limit " principle. This is both interesting
and important, sufficiently so to merit a more
detailed reference.
It must first be realized that no two things are
alike and no measurement is perfectly correct. When
we lightly speak of two things being " alike " we
really mean that for the purpose contemplated they
are nearly enough alike. Two things might be
" alike " for one purpose and yet be so unlike as to
be useless for another.
What the authorities do in the case of shells,
therefore, and what is done nowadays in many
branches of engineering, is to recognize this fact and
at the same time overcome the difficulty by stating
what difference is permissible. In other words,
instead of saying that a thing must be a certain size,
it is required to fall between two limits : it must not
be more than one or less than the other.
For example, suppose a hole is required to be
nominally an inch in diameter it may be specified
that it shall not exceed an inch plus one -thousandth
or fall short of an inch minus one-thousandth. In
such a case a variation of a thousandth of an inch
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SHELLS AND HOW THEY ARE MADE
either way is permitted. The permitted variation
may be more than that, or it may be less and be
measured in ten-thousandths, it all depends upon
circumstances. Clearly in every case it is desirable
to permit as large a variation as is consistent with a
good result.
Now to make measures with the degree of accuracy
just mentioned is not easy. One can just about see
through a crack a thousandth of an inch wide if held
up to a bright light. How then can dimensions such
as these be dealt with easily and quickly in the
rough conditions of a large workshop ?
Let us again think of that one-inch hole and we
shall see how simply and easily it is done. The gauge
in such a case would be shaped somewhat like a
dumb-bell, one end being the " go " end and the
other the " not-go " end. The former is made to
agree as nearly as possible with the lower limit, the
other with the higher limit, and all the inspector has
to do is to try first one end in the hole and then the
other. One must " go " in and the other must
" not-go." So long as that happens he knows that
the hole is correct within the prescribed limits.
If, on the other hand, both go in, then he knows the
hole is too large, or if neither goes in he knows it is too
small. It may be urged by some acute reader that
the gauges themselves cannot be correct, and that is
quite true, but it is possible, by great care and
laborious methods, to produce gauges which are
correct to within far narrower limits than those
mentioned.
In the case of outside dimensions the gauges take
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SHELLS AND HOW THEY ARE MADE
the form of a thumb and finger capable of spanning
the object to be measured, and in that case also two
are used, one of which must " go " and the other
" not-go."
By methods such as these the shells are measured
and examined.
One of the most important features of a shell is
its driving band. In the old days of round cannon
balls it is said that the gunners used to wrap greasy
rag round each so as to make it fit the cannon and to
prevent the force of the explosion to some extent
wasting itself by blowing past the ball. That is one
of the functions of the driving band. It is made of
copper which is comparatively soft, and it forms a
fairly tight fit in the bore of the gun, so that while
the shell is free enough to slide out of the gun it is
tight enough to prevent the loss of any of the driving
force of the explosive.
Its second purpose is to give the necessary spinning
action to the shell. The old cannon ball suffered
from the fact that it offered a considerable surface
to the air in proportion to its weight. The idea arose,
therefore, of making projectiles cylindrical and with
a pointed nose, so that while the weight might be
increased the resistance to the air might be even
reduced. But it was clearly no use doing this unless
the thing could be made to travel point foremost.
Now for some rather mysterious reason, if you shoot
a cylindrical object out of a gun, it will turn head
over heels in the air, unless you give it a spinning
motion. This motion, however, because of a gyro-
scopic effect, keeps the shell point first all the time.
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SHELLS AND HOW THEY ARE MADE
It has another effect, too, known as " air-boring."
A spinning shell seems actually to bore its way
through the air. Probably this is due to a centrifugal
action, the spinning shell throwing the air outwards
from itself and so to some extent sucking the air away
out of its own path. Whether that be the true
explanation or not, the fact remains that the spinning
shell makes its way through the air better than a
non-spinning one would do.
The gun, therefore, has formed in its bore a very
slow screw-thread called " rifling," from a French
word meaning a screw. And it is the second function
of the copper band to catch this rifling and by it be
turned as the shell proceeds along the barrel. The
soft copper conforms to the shape of the rifling and
so itself becomes in a sense a screw engaging with the
rifling.
This band is situated near the base of the shell,
lying in a groove turned in the shell for its reception.
To prevent the band turning round without turning
the shell there is a wavy groove turned in the bottom
of the larger groove, and the band, being put on hot,
is squeezed into the latter by a powerful press.
The nose -bush is a little fitting of brass which
screws into the smaller end of the shell and it has a
hole in its centre into which another brass fitting,
the nose itself, is screwed.
The base of the shell is closed with a little disc of
steel plate. People sometimes wonder why the
original forging is not made solid at the bottom so as
to save the necessity for this disc, but the reason is
that if that were done defects might very possibly
SHELLS AND HOW THEY ARE MADE
arise in the steel in the centre which, since it is the
very spot whereon the propellant acts, might let some
of the heat or force of the propellant through, causing
a premature explosion of the charge inside the gun
itself instead of among the ranks of the enemy.
In the case of naval shells, the nose is not of brass
but of a soft kind of steel. One might expect it to be
of the very hardest steel, since it has to pierce the
hard armour, but experience has shown that the soft
nose is better than a hard one. The reason probably
is that a hard nose splinters, whereas a soft one
spreads out on striking the armour and then acts as a
protection to the body of the shell behind it. In
these shells, too, the fuse which explodes the charge
is placed in the base. In the others it is in the nose,
but clearly it could not be so placed in the armour-
piercing shell.
It is interesting to mention that the propellent
" powder " has combined in it some vaseline or other
greasy matter which acts as a lubricant between the
gun and the shell when firing takes place.
Shrapnel is so different from the other types of
shell that it merits a short paragraph or two to itself.
Instead of being filled, as the others are, solely with
explosive, the front part of it accommodates a con-
siderable number of small round bullets, behind
which comes a charge of gunpowder. The front half
of the shell is separate from the back part, the two
being connected by rivets of soft iron wire, so that a
sudden shock can rend them apart. The shell is
fired from the gun and comes flying along : suddenly,
owing to the action of the fuse, the gunpowder
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SHELLS AND HOW THEY ARE MADE
explodes : the case then flies in two, the bullets are
liberated and fall in a shower. In the South African
War, where fortifications were few, these shells were
very effective, but against fortifications, and par-
ticularly against trenches and barbed wire, big
explosive shells are of much greater value.
CHAPTER XI
WHAT SHELLS ARE MADE OF
THE body of a shell is made of steel of a
fairly strong variety. That is to say, it is
stronger than that used for shipbuilding
and for bridges and such work : but it is less so than
some of the higher grades of steel, such as that used
for making wire ropes. Owing to so much of this
steel being rolled during the war, " shell quality "
has come to be as well known to the general engineer
as any of the many varieties which he has been
accustomed to since his apprentice days. Many
people wondered, at one time, why the cheaper and
more easily worked cast iron could not be used for
shells. There was a period when the steel works
were quite unable to cope with the demands for steel,
yet the iron foundries were crying out for work.
This question then arose in many minds, Why not
make cast iron shells ? The answer is that cast iron
is too weak : it would blow into fragments too
soon.
Just think what a shell is and what it has to do.
It is a metal case filled with explosive. It is thrown
from a gun and is intended to blow itself to pieces on
arrival at its destination. It is that self-destruction
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WHAT SHELLS ARE MADE OF
which carries destruction to all around as well. It is
necessary, in order to obtain the best result, that an
appreciable time should elapse between the ignition
of the explosive and the bursting of the case. The
force of the most sudden explosion is not really
developed at once, but takes an appreciable time.
After ignition, therefore, as the explosion gradually
becomes complete, the pressure inside the shell is
growing, and too weak a shell would go to pieces
before the maximum pressure had been attained.
Thus much of the energy of the explosion would
simply be liberated into the air instead of being
employed hi hurling the fragments of shell with
enormous force.
That is, of course, not a complete explanation of
the whole action of a high-explosive shell, but it
indicates generally the reason why a special quality
of steel is required in order to get the best
results.
Steel having been dealt with in another chapter,
we will pass to the other metals which play important
if not essential parts in the production of modern
projectiles. So important are several of these that
the lack of one or two of them would, under modern
conditions, mean certain defeat for a nation.
Let us first of all take copper, of which is made the
driving bands of the shells and which in combination
with zinc forms brass of which noses and other
important parts are made.
Its ore is found in many parts of the world, notably
in the United States, Chili and Spain. The ores are of
several kinds, the simpler ones to deal with being
WHAT SHELLS ARE MADE OF
oxides and carbonates of copper, meaning compounds
of copper with oxygen and with oxygen and carbon
respectively.
It will be remembered that ores of iron are usually
of the same nature, namely, oxides and carbonates,
and consequently we find that the method of obtaining
copper from these ores resembles the methods
employed to obtain iron from its ores.
The ore is thrown into a large furnace, like the
blast furnaces of the ironworks, and in the heat of the
fire the bonds between copper and oxygen are
loosened and the superior attractions of the carbon
in the fuel entice the oxygen away, leaving the metal
comparatively pure.
Unfortunately, however, copper is found most
plentifully in combination with sulphur with which
it forms what is termed sulphide. This copper
sulphide is called by miners " copper pyrites."
Another trouble is that mixed with the copper
pyrites there is usually more or less of iron pyrites,
or sulphate of iron, so that to obtain the copper not
only has the sulphur to be got rid of but also the
iron. This complicates the operations very much,
the ore having to be subjected to repeated roastings
and meltings during which the sulphur passes off in
the form of sulphur dioxide (a material from which
sulphuric acid can be obtained), leaving oxygen in
its place. Thus the copper sulphide becomes copper
oxide, after which the oxygen is carried away by
carbon, leaving the relatively pure metal. Moreover,
at each operation various substances are thrown into
the furnace called fluxes, which do not mingle with
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WHAT SHELLS ARE MADE OF
the metal but float on the top in the form of slag,
and into the slag the iron passes, so that finally the
copper is obtained alone.
Zinc is another important material for shell-
making. Its ores used to be found in great plenty
in Silesia, but the chief source of supply is now
Australia. It is what is called " zinc blende," and
consists of zinc sulphide, or zinc and sulphur in
combination. In all these names, it may be interest-
ing to mention, at this point, the termination "ide"
indicates a compound of TWO substances, so that we
can safely conclude that the " ides " consist of the
two elements named in their titles and no others.
Thus zinc sulphide is zinc and sulphur and nothing
else, iron sulphide is iron and sulphur, copper oxide
is copper and oxygen, and so on.
The blende is first roasted in huge furnaces
specially built for the purpose. To ensure its being
thoroughly treated it has to be " rabbled " or turned
over and over, since otherwise all of it might not be
brought into contact with the necessary oxygen. At
one time done by men with rakes, it is now generally
accomplished by mechanical means.
A description of one such furnace will be of
interest. It consists of a long rectangular building
of brickwork bound together with steel framework.
Inside it is divided up into low chambers, the roof
of each forming the floor of the one above.
At intervals along its length mighty shafts of iron
pass up from underneath right through all the
floors, emerging finally above the topmost, while along
underneath the furnace there runs a shaft the action
149
WHAT SHELLS ARE MADE OF
of which turns the vertical shafts slowly round and
round.
Attached to the vertical shafts are long strong
arms of iron, one arm to each floor, and upon the
arms are placed rabbles, as they are termed, pieces of
iron shod sometimes with fireclay, resembling most
of any familiar objects a small ploughshare.
As the arms slowly revolve, at the rate of once or
twice per minute, the arms are carried round and
round and the rabbles plough up and turn over and
over the layer of ore lying upon the floor.
There are arms on the top of the furnace, too,
sometimes, where the ore is first laid so that it may
be dried by the heat escaping from the furnace
beneath, an interesting example of economy ef-
fected by utilizing heat which would otherwise be
wasted.
The whole of the furnace, from end to end and on
every floor, is thus swept continually by the rotating
arms with their dependent rabbles, and the latter are
cunningly shaped so that they not only turn the ore
over and over, but gradually pass it along the different
floors or hearths. It is fed automatically by a mechani-
cal feeder which pushes it on, a small quantity at a
time, to the drying hearth on the top. Then the rabbles
take charge of it and gradually pass it from the area
swept by one shaft to that of the next until it has
passed right along the top and has become thoroughly
dried. Arrived there it falls through a hole on to the
topmost hearth or floor, along which it travels by the
same means but in the contrary direction until it
again falls through a hole on to the top floor but one.
150
WHAT SHELLS ARE MADE OF
And so it goes on until at last, fully roasted, it falls
from the bottom floor of the furnace into trucks or
other provision for carrying it away.
Some kinds of ore require to be heated by means
of gas which is generated in a " gas-producer " near
by. In others, however, the sulphur in the ore acts
as the fuel, and so the furnace, having been once
started, can be kept up for long periods without the
expenditure of any coal at all. Very little attention
is needed by furnaces such as these, so that with no
fuel to pay for and very little labour, they are
extremely economical.
Owing to the great heat, too, the arms would stand
a very good chance of getting melted were they not
kept cool by a continual stream of water flowing
through the shafts and arms. This furnishes a con-
tinual supply of hot water which is sometimes used
for other purposes in the works.
The process of roasting, whether carried on in
furnaces such as these or not, results in the formation
of oxide instead of sulphide; in other words, the
sulphur is turned out and oxygen takes its place.
The dislodged sulphur then joins up with some more
oxygen and forms sulphur dioxide, which can be led
away to the sulphuric acid plant and there, by union
with water, turned into that extremely valuable
substance, sulphuric acid.
We cannot, however, treat zinc oxide as we would
iron oxide or copper oxide, for zinc is volatile, and so,
instead of accumulating in the bottom of a blast
furnace as the iron and copper do, would pass off
up the chimney.
WHAT SHELLS ARE MADE OF
The oxide is therefore mixed with coal or some
other form of carbon and placed in retorts made of
fireclay. These retorts are fixed in rows one above
the other like the retorts at a gasworks, and hot
gases from a gas-producer down below pass around
and among them. To the mouth of each retort is
fitted a condenser, also made of fireclay.
Now what happens in the retorts is this : the
heat loosens the bonds between the zinc and the
oxide, the latter passing into union with some carbon
from the coal. The zinc at the same time becomes
vapour and passes into the condenser, the lower
temperature of which turns it into a liquid which
the workmen remove at intervals in ladles. On
being poured into moulds and allowed to solidify this
metal is called by the name of " spelter," which
bears to zinc the same relation that pig-iron does to
the more highly developed forms of iron. Spelter is
simply zinc in its crudest form.
Tin, although less important in war than copper
and zinc, plays a not unimportant part. It has been
found for centuries in Cornwall. The Romans used to
trade with the natives of Britain for tin. Although
considerable quantities of it is still obtained from
there,the greatest tin-producing country of all at
present is the Federated Malay States. Australia also
furnishes ore, as does Bolivia and Nigeria.
In Cornwall the ore occurs as rock in veins or lodes
filling up what must once have been fissures in
granite rocks. That near the surface has long been
taken, so that to-day the mines are very deep and
costly to work. Some can only afford to operate
152
WHAT SHELLS ARE MADE OF
when the market price of tin is above a certain limit.
Much of the ore from the newer districts the Malay
States, for example is in small fragments mixed with
gravel in beds near the surface. Such is called
alluvial or stream tin, since the deposits were un-
doubtedly put in their present position by streams or
rivers. So long as they last these easily accessible
alluvial deposits will always be cheaper to work
than the deep mines. On the other hand, they may
give out, and recent explorations underground seem
to indicate that there is still much valuable ore not
only of tin but of other metals too, to be obtained
from the old mines of Cornwall.
The ore of tin, like so many other ores, is generally
oxide. It is first roasted to expel sulphur and arsenic
which are often present as impurities, and then it is
melted in a reverberatory furnace such as that
described for the manufacture of wrought iron. As
usual, the oxygen combines with carbon, the im-
purities form slag which floats on the top, and the
pure metal falls to the bottom of the furnace from
whence it can be drawn off.
Mixed with or in the neighbourhood of tin ore
there is sometimes found another mineral called
wolfram, which plays an extremely important part in
modern warfare, so much so that the British and
other Governments engaged in the war were at times
hard put to it to find enough. Its value resides in the
fact that it contains tungsten, an element which
has wonderful powers in hardening steel.
It consists of tungsten and oxygen, but is not an
oxide since there is also iron in the partnership. This
'53
WHAT SHELLS ARE MADE OF
fact is very useful, however, since it enables the
particles of wolfram to be picked out from the mass
of other stuff among which they are found by a
magnet.
There are some very wonderful machines called
magnetic separators, made for this express purpose.
In one, with which I am familiar, there is an endless
band stretched horizontally upon two rollers. One
of the rollers being driven round the belt travels
along so that the mineral being fed on to it in a
stream is carried along under several magnets. These
magnets are very different from the ordinary magnet,
inasmuch as they are revolving. We might almost
describe them as small magnetized flywheels. As
they spin round they pick up slightly the particles of
ore which contain iron, but have no effect at all upon
those which do not contain iron. They do not
actually lift the particles up on to themselves : they
just exercise a slight pull upon them, and by virtue of
the fact that they are revolving, pull them off the
band and throw them to one side. The wheels can
be set closer or farther from the belt at will so as to
make them act more or less strongly, and thus the
most magnetic particles can be separated from those
less magnetic, these latter being still kept separate
from the wholly non-magnetic particles. Thus by
simple and purely mechanical means are the precious
bits of wolfram obtained from the other less
valuable or worthless minerals with which they are
mixed.
The same method is used with other minerals
besides wolfram : it can be applied to all those which
WHAT SHELLS ARE MADE OF
exhibit in some small degree the magnetic properties
which we usually associate with iron.
This sorting out of one mineral from others con-
tinually crops up in connection with nearly all the
metals except iron. Iron is practically the only one
whose ore occurs in vast masses which need simply
to be dug up and thrown into the furnace. The
others, where they occur as rock in veins, have to be
crushed to detach what is wanted from what is not
wanted, and then the two have to be sorted in some
way. Magnetic separation is but one of these ways.
Another takes advantage of the fact that we seldom
find two things together which have precisely the
same specific gravity. Consequently, if we throw the
mixture on to a shaking table the heavier particles
will behave differently from the lighter ones and the
two will separate. The same result can be obtained by
throwing the mixture into a stream of water, the
water acting differently upon the lighter and upon
the heavier particles. Another way which may be
mentioned is founded upon the fact that some things
can be readily wetted with oil while others throw the
oil off and refuse to be wetted by it. If a mixture of
these two sorts of thing be stirred violently in a
suitable oily liquid the former will be found eventu-
ally in the froth, while the latter will sink to the
bottom. All these different methods are employed,
as they are found necessary in preparing the ores
of the various metals to which we have been
referring.
Except in the case of alluvial ores which have been
broken already by the action of ancient streams of
'55
WHAT SHELLS ARE MADE OF
water, nearly all ores (except iron) have to be crushed
before the ores can be separated out. Some of this
work is done by the very simplest contrivances,
showing how in some cases invention has almost come
to a stop through the machines having been reduced
to their simplest form. A notable instance of this
is the stamp mill, in which heavy timbers are lifted
up by machinery and then allowed to slide down
upon the ore, just like gigantic pestles. More
elaborate grinding machines are sometimes used,
however, but it is impossible to mention them all
here.
The action of sorting out the fragments of ore from
the miscellaneous assortment of crushed rocks is
termed " concentrating," and the sorted ores are
called " concentrates."
Another metal which has proved itself of immense
importance in war is aluminium, and it fittingly comes
at the close of the list since it is dealt with in a
manner peculiar to itself. Practically all the others
are obtained from their ores by means of heat and
heat alone. Aluminium is obtained by electricity
acting in the process called electrolysis.
It is surprising to learn that aluminium is one of the
very commonest things on the face of the earth.
Clay and many common rocks are very largely made
of it. Clay, to be precise, is a silicate of alumina,
a term which is interesting when it is explained.
Silica is the name given to oxide of silicon. Sand
is mostly silica. Alumina, too, is oxide of alu-
mimium. Silicate of alumina is a combination of
the two.
156
WHAT SHELLS ARE MADE OF
Any clay, therefore, could be used as an ore from
which to obtain aluminium, but of course there are
certain minerals specially suitable for the purpose,
since in them the metal is plentiful and easily
extracted.
In another chapter reference is made to the pro-
duction of caustic soda from a solution of common
salt by electrolysis. The same principle, precisely, is
used to obtain the metal aluminium from its ore,
which is generally an oxide.
Common salt, let me remind you, is sodium and
chlorine combined. When you dissolve it in water
it becomes ionized, which means that each molecule
of salt splits up into two ions one of which is electri-
cally positive and the other electrically negative.
Then, when we introduce two electrodes into the
solution and connect them to a battery or dynamo,
all the positive ions go to one electrode and all the
negative ions to the other.
We cannot dissolve aluminium ore in water, but
we can in a bath of molten cryolite, and for some
reason or other, whether because of the heat or not
we cannot say, the ore becomes ionized, the aluminium
atoms being one sort and the oxygen atoms the
other sort. These ions then sort themselves out,
the oxygen ions being taken into combination with
the carbon rod which forms the positive electrode,
while the metal ions collect upon the negative
electrode. Since this latter is a slab of carbon
which forms the bottom of the vessel in which
the process is carried on, the result is that pure
aluminium gradually accumulates in the bottom of
WHAT SHELLS ARE MADE OF
the vessel and can be drawn off from time to
time.
Aluminium is always produced in places where
electric power can be obtained cheaply, such as near
waterfalls.
158
CHAPTER XII
MEASURING THE VELOCITY OF A
SHELL
IN at least two of the preceding chapters of this
book reference has been made to the speed at
which a shell fired from a gun travels through
the air. Such velocities as 3,000 feet per second
have been mentioned in this connection, and some
readers are sure to have wondered how such measure-
ments could possibly be made. Possibly some
sceptics have even supposed that they were not
measured at all but simply estimated in some way or
other. They are actually measured, however, and by
very simple and ingenious means.
Needless to say, electricity plays a very important
part in this wonderful achievement. In fact, with-
out the aid of electricity it is difficult to see how it
could be done at all.
People often ask how quickly electricity travels, as
if when we sent a telegraph signal along a wire a
little bullet, so to speak, of electricity were shot along
the wire like the carriers of the pneumatic tubes in
the big drapers' shops. That is quite a miscon-
ception, for in reality the circuit of wire is more like
a pipe full of electricity, and when we set a current
flowing what we do is to set the whole of that
THE VELOCITY OP A SHELL
electricity moving at once. If we think of a circular
tube full of water with a pump at one spot in the
circuit, we see that as soon as the water begins to
move anywhere it moves everywhere. Moreover, if
it stops at one point it stops simultaneously at every
other point. While practically this is the case it is
theoretically not quite so, for the inertia of the water
when it is suddenly started or stopped no doubt
causes a slight distortion of the tube itself resulting
in a very slight (quite imperceptible) retardation of
the movement of the water. Electricity also has a
property comparable to the inertia which we are
familiar with in the objects around us, and there is
also a property in every conductor which to a certain
extent resembles the elasticity of the water-pipe,
whereby it may for a moment be bulged out. In a
short wire, however (up to a mile or so), particularly
if the flow and return parts of the circuit be twisted
together, this electrical inertia practically vanishes
and consequently we may say that for all practical
purposes the current starts or stops, as the case may
be, at precisely the same moment in every part of the
circuit.
That fact is of great value when, as in the case we
are now discussing, we want to compare very exactly
two events occurring very near together as to time
but far apart as to place.
We need to compare the time when the shell leaves
the gun with the time when it passes another point,
say, one hundred yards away, and then again another
point, say one hundred yards further on still. Sup-
posing, then, a velocity of 3,000 feet per second,
160
BOMB-THROWERS AT WORK.
Many kinds of bombs are used. One has a metal head and a handle about a foot long,
with a streamer to ensure correct flight ; another form resembles a biush when it is flying
through the air ; and a third, known as " the egg," is oval in form.
THE VELOCITY OF A SHELL
the time interval between the first point and the
second and between the second and third will be
somewhere about a tenth of a second. So we shall
need a timepiece of some sort which will not only
measure a tenth of a second, but will measure for us
a very small difference between two periods, each of
which is only about a tenth of a second and which will
be very nearly alike. That represents a degree of
accuracy exceeding even what the astronomers, those
princes of measurers, are accustomed to.
This exceedingly delicate timepiece is found in a
falling weight. So long as the thing is so heavy that
the air resistance is negligible, we can calculate with
the greatest nicety how long a weight has taken to
fall through a given distance.
Near the muzzle of the gun there is set up a frame
upon which are stretched a number of wires so close
together that a shell cannot get past without breaking
at least one of them. These wires are connected
together so as to form one, and through them there
flows a current of electricity the action of which,
through an electro-magnet in the instrument house,
holds up a long lead weight.
At some distance away, say one hundred yards,
there is a similar frame also electrically connected to
an electro-magnet in the same instrument house.
This second magnet, when energized by current from
the frame, holds back a sharp point which, under the
action of a spring, tends to press forward and scratch
the lead weight. The third frame is likewise con-
nected to a third magnet controlling a point similar
to the other.
L 161
THE VELOCITY OF A SHELL
To commence with, current flows through all three
frames so that all three magnets are energized. The
gun is then fired and immediately the shell breaks a
wire in the first frame, cutting off the current from
the first magnet and allowing the weight to fall.
Meanwhile, the shell reaches the second frame,
breaking a wire there, with the result that the second
magnet loses its power, lets go the point which it
has been holding back and permits it to make a
light scratch upon the falling weight. This action is
followed almost immediately by a similar action on
the part of the third magnet, resulting in a second
scratch on the lead weight.
The position of these two scratches on the weight
and their distance apart gives a very accurate
indication of the time taken by the shell to pass
from the first screen to the second and from the
second to the third. From those times it is possible
to calculate the initial velocity of the shell and the
speed at which it will move in any part of its course.
Indeed, with those two times as data, it is possible to
work out all that it is necessary to know about the
behaviour of the shell.
This is rendered practicable by the fact that the
moment the wire is cut the magnet lets go, no matter
what the distance of the screen from the instrument
may be. But for the instantaneous action of the
current, allowance of some sort would have to be
made for the fact that one screen is farther than
another and the whole problem would be made much
more complicated.
Even as it is, someone may urge that the magnets
162
THE VELOCITY OF A SHELL
themselves possess inertia and will not let go quite
instantaneously, but that can be overcome by making
the magnets all alike so that the inertia will affect all
equally. It is only necessary to have a switch which
will break all the three circuits at the same moment
(quite an easy thing to arrange) and then adjust all
three magnets so that when this is operated they act
simultaneously. After that they can be relied upon
to do their duty quite accurately.
Thus by a method which in its details is quite
simple is this seemingly impossible measurement
taken.
163
CHAPTER XIII
SOME ADJUNCTS IN THE ENGINE
ROOM
BEFORE we deal with the subject of the engines
employed in warfare, it may be interesting
to mention two beautiful little inventions
which have been made in connection with them.
Let us take first of all a contrivance which tells
almost at a glance the amount of work which the
engines of a ship are doing.
As everyone knows, there is in every ship (except
those few which are propelled by paddles) a long steel
shaft, called the tail-shaft, which runs from the
engine situated somewhere near amidships to the
propeller at the stern. Many ships, of course, have
several propellers, and then there are several shafts.
Now each of these shafts is a thick strong steel rod
supported at intervals in bearings. If anyone were
told that, in working, that shaft became more or less
twisted, he would be tempted to think he was being
made fun of. Yet such is literally the case. The
thick strong massive bar becomes actually twisted by
the turning action of the engine at one end and the
resistance of the propeller at the other. And the
amount of that twisting is a measure of the work
which the engine is doing. The puzzle is how to
164
IN THE ENGINE ROOM
measure it while the engine is running, for of course
the twist comes out of it as soon as the engine stops.
A space on the shaft is selected, between two
bearings, for the fixing of the apparatus. Near to
each bearing there is fitted on to the shaft a metal
disc with a small hole in it. On one of the bearings
is fixed a lamp and on the other a telescope. When
the engine is at rest and there is no twist in the shaft,
all these four things the lamp, the two holes, and
the telescope are in line. Consequently, on looking
through the telescope the light is visible. But when
the engine is at work and the shaft is more or less
twisted one of the holes gets out of line and it
becomes impossible to see the light through the
telescope. A slight adjustment of the telescope,
however, brings all four into line again, which
adjustment can be easily made by a screw motion
provided for the purpose. And the amount of adjust-
ment that is found necessary forms a measure of the
amount of the twisting which the shaft suffers and
that again tells the number of horse-power which the
engine is putting into its work.
But it is also necessary to know how fast the engine
is working. There are many devices which will tell
this, of which the speedometer on a motor-car is a
familiar example. Most of those work on the centri-
fugal principle, the instrument actually measuring
not the speed but the centrifugal force resulting from
the speed, which amounts to the same thing. There
is one instrument, however, which operates on quite
a different principle, because of which it is specially
interesting. It consists of a nice-looking wooden box
165
IN THE ENGINE ROOM
with a glass front. Through the glass one sees a row of
little white knobs. If this be placed somewhere near
the engine while it is at work immediately one of the
knobs commences to move rapidly up and down, so
that it looks no longer like a knob but is elongated
into a white band. There is no visible connection
between the instrument and the engine, yet the
number over that particular knob which becomes
thus agitated indicates the speed of the engine.
Let us in imagination open the case and we shall
find that the knobs are attached to the ends of a
number of light steel springs set in a row. The
springs are all precisely alike except for their length,
in which respect no two are alike. Indeed, as you
proceed from one side of the instrument to the other
each succeeding one is a little longer than the previous
one. Now a spring has a certain speed at which it
naturally vibrates and other things being equal that
speed depends upon its length. You can, of course,
force any spring to vibrate at any speed if you care
to take the trouble, but each one has its own natural
speed at which it will vibrate under very slight
provocation.
Every engine is, of course, made to run as smoothly
as possible. All revolving or reciprocating parts are
for this reason carefully balanced and in turbines the
whole moving part, since it is round and symmetrical,
naturally approaches a condition of perfect balance.
Hence every engine ought to run perfectly smoothly.
As a matter of fact, however, no engine ever does.
There are certain limitations to man's skill and at
the high speed of a fast -running engine, such as is to be
1 66
IN THE ENGINE ROOM
found on a destroyer, for example, some little irregu-
larity is sure to make itself felt by a slight vibration
in the floor. It may be hardly perceptible to the
senses, but to a spring whose natural frequency
happens to be just that same speed or nearly so, it
will be very apparent and in a few seconds that spring
will be responding quite vigorously.
It is another example of the principle of resonance,
which is employed so finely in making wireless
telegraph apparatus selective. Every wireless
apparatus is made to have a certain natural frequency
of its own and it therefore picks up readily those
signals which proceed from another station having
the same frequency while ignoring those from others.
In just the same way a reed or spring in this speed-
indicator picks up and responds to impulses derived
from the engine only when they are of a frequency
corresponding with its own natural frequency.
Hence, one spring out of the whole range responds to
the vibrations of the engine while the others remain
almost if not entirely unaffected.
In another form, the springs are actuated electri-
cally. A magnet, or a series of magnets, is arranged
so that as the engine turns the magnets pass suc-
cessively near to a coil of wire, thereby inducing
currents in that wire. They form, in fact, a small
dynamo or generator, generating one impulse per
revolution or two or three or whatever number may
be most convenient. Then the current from this is
led round the coil of a long electro-magnet placed
just under the free ends of all the springs. The
magnet therefore gives a series of pulls, at regular
167
IN THE ENGINE ROOM
intervals, and the rapidity of those pulls will depend
upon the speed of the engine, while the frequency of
them will be registered by the movement of one or
other of the springs.
This instrument can also be employed to determine
the speed of aeroplane motors and, in fact, any kind
of engine, especially those whose speed is very high.
168
CHAPTER XIV
ENGINES OF WAR
THE phrase which I have used for the title of
this chapter is often given a very wide mean-
ing which includes all kinds and varieties of
devices used in warfare. In this case I am giving it
its narrower sense, taking it to indicate the steam-
engines and oil-engines which are employed to drive
our battleships, cruisers and destroyers, our sub-
marines and our aircraft. They are inventions of the
highest importance, which have played a large part
in shaping modern warfare.
The type of engine almost invariably used on ships
of war other than submarines is the steam turbine.
Great Britain, for the most part, uses that particular
kind associated with the name of the Hon. Sir C. A.
Parsons, while the United States rather favour the
Curtiss machine. Other nations have adopted either
one of these or else something very similar.
All turbines are very simple in their principle, far
more so that the older type of steam-engine, called,
because the essential parts of it move to and fro, the
" reciprocating " steam-engine.
In these latter machines there are a number of
cylinders with closed ends and with very smooth
interiors, in each of which slides a disc-like object
169
ENGINES OF WAR
called a piston. The steam enters a cylinder first
at one end and then at the other, thus pushing the piston
to and fro. The movement of the piston is communi-
cated to the outside by means of a rod which passes
through a hole in the cover at one end of the cylinder,
the to and fro motion being converted into a round
and round motion by a connecting-rod and crank
just as the up and down motion of a cyclist's knees is
converted into a round and round motion by the
lower leg and the crank. The lower part of a cyclist's
leg is, indeed, a very accurate illustration of what the
connecting-rod of a steam-engine is.
As is evident to the hastiest observer, some
arrangement has to be made whereby the steam shall
be led first into one end and then into the other end
of the cylinder : also that provision shall be made for
letting the steam out again when it has done its work.
Moreover, such arrangements must be automatic.
Hence, every reciprocating engine has special valves
for this purpose and such valves need rods and
cranks (or something equivalent) to operate them.
Further, to get the best results the steam must not
simply be passed through one cylinder but through
several in succession. Engines where the steam goes
through only one cylinder are called " simple,"
where it goes through two they are " compound,"
where three " triple-expansion," where four " quad-
ruple-expansion." Generally speaking, each cylinder
has its own connecting-rod and crank, also its own
set of rods, etc., for working its valves. Hence, a
high-class marine reciprocating engine is of neces-
sity a complicated mass of cylinders, rods, cranks
170
ENGINES OF WAR
and other moving parts continually swinging round
or to and fro at considerable speeds, all needing
oiling and attention and all liable at times to give
trouble.
And now compare that with the turbine, which
has TWO parts, only one of which moves. That part,
moreover, is tightly shut up inside the other one,
being thereby protected from any chance of damage
from outside and likewise rendered unable to inflict
any damage upon those in attendance upon it.
At first sight it seems very strange that the
turbine should be the newer of the two, for it is
simply an improved form of the old time-honoured
picturesque windmill which used to top every hill and
grind the corn for every village and hamlet.
The old windmill had four sails against which the
wind blew, driving the whole four round as everyone
knows. The new turbine has a great many sails,
only we now call them blades, and the steam blows
them round. The old windmill had to have another
smaller set of sails at the back for the purpose of
keeping the main sails always in that position in
which they would catch the full force of the breeze.
In the turbine we need not do that, for we shut the
windmill up in a kind of tunnel and cause the steam
to blow in at one end and out at the other.
The difference between the various kinds of turbine
lies simply in the manner in which the steam is guided
in its passage through the machine.
After that general description we can take a more
detailed view of the Parsons turbine. The casing or
fixed part is a huge iron box suitably shaped for
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ENGINES OF WAR
standing firmly and rigidly upon the floor of the
engine-room. It is made in two halves, the upper
of which can be easily lifted off when necessary.
Often, indeed, this upper half is hinged to the lower,
so that it can be opened like the lid of a box.
Inside, the casing is cylindrical, comparatively
small at one end but increasing by steps till it is very
much larger at the other end. At each end is a
bearing or support in which the rotor or moving
part is held and in which it can turn freely.
The rotor or part which rotates is a strong steel
forging shaped somewhat to follow the lines of the
inside of the casing. It does not entirely fill the
casing but leaves a space all round and all the way
along, which space is intended to accommodate the
blades. The ends of the rotor are smaller than the
body since they are intended to fit into the bearings,
and one of the ends is prolonged so as to be available
for coupling to the propeller-shaft of the ship.
At one end of the casing, the smaller one, is the
steam inlet and the steam after emerging from it
passes along till it finds its way out at a very large
outlet formed at the bigger end. On its way it has
to pass thousands of small blades so that the progress
of each individual particle of steam is not a straight
line but a continual zigzag. There are rings of
blades round the rotor, tightly fixed to its surface.
There are likewise rings of blades affixed to the inner
surface of the casing, the rings upon the casing coming
in the spaces between the rings on the rotor.
Let us imagine that we can see through the casing
of a turbine at work and that looking down upon it
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ENGINES OF WAR
from above we can trace the progress of a particle of
steam. It rushes in from the inlet and at once makes
straight for the outlet at the further end. Suddenly,
however, it encounters one of the guide blades (those
on the case) and by it is deflected to one side, we will
suppose the left. That causes it to rush straight at
one of the blades upon the rotor against which it
strikes violently, giving that blade a distinct and
definite push to the left. Rebounding, it then comes
back towards the right but quickly is caught by
another guide blade and by it hurled back upon a
second rotor blade, giving it a leftward push just as
it did to the first. Thus it goes zigzagging from one
set of blades to the other until, tired out, so to speak,
it finally flows away forceless and feeble through the
outlet, having given up all its energy to the blades
of the rotor against which it has struck in its
course.
That, then, is the journey of one single particle.
Multiply that by an unknown number of millions and
you have a description of what takes place in the
interior of a steam turbine. The blades are so pro-
portioned, so arranged and so placed that it is very
difficult indeed for a particle of steam to creep past
without doing its share of work. Practically every
one is made use of and while, of course, the action
of a single particle of steam would have but a
negligible effect, the vast number engaged cause the
rotor to be powerfully blown round.
The reason why the casing and rotor are made larger
and larger as one proceeds from the inlet towards the
exhaust or outlet is that the steam must, if all its
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ENGINES OF WAR
energy is to be extracted, expand as it goes and the
enlargement provides room for this expansion.
One of the great advantages of the turbine is that
the steam is always entering at the same end. In the
cylinder of a reciprocating engine the steam enters
alternately. It comes in hot but as it does its work
and finally goes out it becomes very much cooler :
the next lot of steam which enters, therefore, is
chilled by the cool walls of the cylinder which have
just been cooled by the departure of the previous lot
of steam : so heat is wasted. Wasted heat means
fuel lost, and as any given ship can only carry a
limited quantity of fuel, wasted heat means less
range and more frequent returns to the base to coal
or to " oil."
Also let me remark again upon the simplicity of the
turbine as opposed to the other sort. The latter
consists of a mass of moving and swaying rods and
cranks, to work among which, as the engineers have
to do, is a terrifying and nerve-racking experience.
The turbine, on the other hand, has its only working
part enclosed. It is difficult to tell, by looking at it,
whether a turbine is at work or not, so silent and
still is it, so self-contained. The reciprocating
engine-room is noisy and full of turmoil : the turbine
room is weirdly still by comparison.
On the whole, too, it makes better use of the steam
which it uses, but it has one decided drawback. It
will not reverse, which the other type of engine does
readily.
This means that two turbines have to be coupled
together, one with the blades so set that the steam
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ENGINES OF WAR
drives it round correctly to produce motion ahead and
the other set the opposite way so that it drives the
vessel astern. The steam can be sent through either
turbine at will and so motion can be obtained in
either direction. Whichever turbine is in use the other
revolves idly.
Unfortunately it is impossible to make a turbine to
go slowly and yet be efficient. Consequently, slow
steamers cannot use turbines, but for warships, which
are nearly all fast boats, it has almost displaced the
older type of engine.
The Curtiss turbine is different from the Parsons
in that the steam encounters periodically, in its
passage through, a partition perforated with funnel-
shaped holes. Between the partitions it passes blades
upon which it acts just as already described. The
chief effect of this is to permit the machine being
made of a rather more convenient shape and size.
Other varieties of turbine are more or less combina-
tions of the two ideas underlying these two.
When we look at a locomotive in motion we always
see steam coming out of the funnel, but we never
see that in the case of a steamer. That is because all
the energy of the steam is taken and used in the latter
case, while in the former much valuable energy goes
off up the funnel, making a puffing noise instead of
doing useful work.
On the steamship the steam is led not to the
open air but to a vessel called a condenser the walls
of which are kept cool by a continual circulation of
cold water. The steam on entering the condenser
at once collapses into water, leaving a vacuum.
ENGINES OF WAR
A pump called the " air-pump " removes the water
(which was once steam) from the condenser and also
any air which might get in, with the result that the
engine is always discharging its steam into a vacuum.
Thus to the pressure of the steam is added the
suction of the vacuum.
In turbine ships the cooling water for the con-
densers is circulated by powerful centrifugal pumps
driven by subsidiary engines.
The steam is obtained from boilers of that special
variety known as " water-tube."
The boilers with which most people are familiar
are either Lancashire or Cornish, both sorts being
large steel cylinders with two steel flues in the
former and one in the latter running from back to
front. The fire is made in the front part of the flue and
the hot gases from it pass to the back and then along
the sides and underneath through flues formed in
the brickwork in which the boiler is set. Locomotive
boilers, however, have no flues, but the hot gases
from the fire in the fire-box pass through tubes which
run from end to end through the cylindrical shell,
each tube starting from the fire-box behind and
terminating in the smoke-box in front. Thus we have
tubes with fire inside and water outside : hence such
boilers are called " fire-tube " boilers.
On many ships of the merchant type cylindrical
boilers are used which combine the features, to some
extent, of the Cornish and the fire-tube, since there is
a flue running from front to back in which the fire is
made and the hot gases return from back to front
through a number of tubes which occupy the space
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ENGINES OP WAR
above the fire. Arrived at the front the gases pass
upwards to the chimney.
Water-tube boilers are different from all of these,
since in them the water is inside the tubes while the
fires play around the outside. This enables steam to
be got up very quickly, a matter of much importance
for a warship which may be called upon to undertake
some operation at a moment's notice.
The boilers are fed with water from the con-
densers, so that the same water is used over and over
again. When coal is burnt it is put on the fires by
hand, for although mechanical stoking is a great
success on land, there are special difficulties which
prevent its use at sea. It is becoming more and more
the fashion now to burn oil instead of coal in several
types of ships and in those cases the oil is blown in
the form of spray into the furnace. This has many
advantages, some of which are exemplified on a small
scale by the difference between using a coal fire and
a gas stove. Like the latter, the oil spray can be
quickly lit when needed and as quickly extinguished.
It can be regulated and adjusted with equal facility.
Oil can be taken on board too through a pipe,
silently and quickly and without the terrible dirt
and the exhausting labour involved in coaling a big
ship. Oil, too, can be taken on board at sea, from a
tank steamer, almost as easily as it can be taken in
ashore, whereas the difficulty of coaling at sea
despite many ingenious efforts has never been solved
quite satisfactorily. Finally, oil can be stowed any-
where, for the stokers do not need to dig it out with a
shovel. Therefore it can be carried in those spaces
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ENGINES OF WAR
between the inner and outer bottoms which have to
be there in order to give strength to the ship's hull
but which would be quite useless for carrying coal.
The advantages of oil fuel, therefore, are many and
no doubt it will be used more and more as time
goes on.
For Great Britain, oil fuel has the disadvantage
that it has to be imported whereas the finest steam
coal in the world is found in abundance in South
Wales, but the difficulty may eventually be overcome
by distilling from native coal an oil which will serve
as well as that which is now imported.
So much for the turbine, the engine of the big
ships : now for the Diesel oil-engine which drives the
submarines. It belongs to that family of engines
called " internal-combustion " since in them the fuel
is burnt actually inside the cylinder and not under a
separate contrivance such as a boiler. There have
been oil-engines, so called, for many years, but they
were really gas-engines since the oil was first heated
till it turned into vapour and then that vapour was
used as a gas. The Diesel engine, however, actually
burns oil in its liquid state.
To understand how it works let me ask you to
conjure up this little picture before your mind's eye.
A hollow iron cylinder is fixed in a vertical position :
its upper end is closed but its lower end is open :
inside it is a piston, free to slide up and down : by
means of a connecting-rod hinged to it and passing
downwards through the open lower end the piston is
connected to a crank and flywheel. At the upper
end of the cylinder are certain openings which can be
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ENGINES OF WAR
covered and uncovered in succession by the action of
suitable valves.
Now let us assume that that engine is at work, the
piston going rapidly up and down in the cylinder.
As it goes down it draws in a quantity of air through
a valve which opens to admit the air at just the
right moment. The moment the piston reverses its
movement and starts to go up again that valve
closes and the air is entrapped. The piston con-
tinues to rise, however, with the result that the air
becomes compressed in the upper part of the
cylinder.
Now it is necessary to remind you at this point
that compressing air or indeed any gas, raises its
temperature. This air, therefore, which was drawn
in at the temperature of the outer atmosphere, by the
time the piston has reached the top of its stroke has
attained a temperature well above the ignition point
of the oil fuel.
The piston, having arrived at the top of its stroke, the
upper part of the cylinder is filled with hot compressed
air : the next moment the piston commences its
descent, but at precisely that same moment a valve
opens and there is projected into the cylinder a spray
of oil. Instantly it bursts into flame, heating the
ah* still more, so that as the piston descends the air,
expanding with the heat, pushes strongly and
steadily upon it. The amount of that push can be
varied by varying the duration of the jet. The
longer the jet is injected the more heat is generated
and the more sustained is the push. On the other
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ENGINES OF WAR
hand, if the jet is cut off very quickly the push is
only a gentle one.
The power of the engine can thus be adjusted to
suit varying circumstances by a slight variation in
the valve which controls the jet.
The piston having thus been driven down to the
limit of its stroke, it commences another upward
movement, at which moment another valve opens
and lets out the hot waste gases which have resulted
from the burning of the oil. Thus the cylinder is
cleaned out ready for a fresh supply of pure air to be
drawn in on the next ensuing downstroke.
The engine thus works upon a series or cycle of
operations which are repeated automatically over and
over again. First comes a downstroke, drawing in
air : then an upstroke, compressing it : then a
second downstroke, during which the fuel burns and
the power is generated : and, finally, a second up-
stroke during which the waste products of the burn-
ing are ejected. Power, it will be noticed, is only
developed in one out of the four strokes : the other
movements having, in single cylinder engines, to be
performed by the momentum of the flywheel.
In most cases, however, the engine has several
cylinders in which the cycles are arranged to follow
in succession. Thus, if there are four cylinders,
there is always power being developed by one of
them.
The valves are operated automatically by the
engine itself just as is the case with steam-engines.
The engine also works a small pump which provides
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ENGINES OF WAR
the very highly compressed air necessary to blow the
oil jet into the cylinder.
Arrangements are often provided whereby the
engine when working stores up a reserve of com-
pressed air which can be used to start it. From the
very nature of its working such an engine cannot
develop power until it has accomplished at least four
strokes or two revolutions, so that it cannot possibly
start itself. If, however, compressed air be admitted
to the cylinders to give it a vigorous push or two
and so get it going, it can then take up its own work
and go on indefinitely.
In some cases this is not necessary and that of an
engine in a submarine is one of them. In that
instance, the electric motor, which drives the boat
when submerged, can be made to give the engine a
start.
By altering the rotation in which the valves act
the direction can be reversed. A very simple
mechanism can be made to effect this change, so that
reversing is quite easy.
Aircraft are mostly, if not entirely, driven by
petrol engines, some of which are very little different
from those of a motor-car or motor-cycle.
These motor-car engines are so well known that
little need be said about them. It may be well to
explain, however, that they, like the Diesel engines,
work on a cycle of four strokes, as follows :
First stroke (down) draws in a mixture of air
and gas.
Second stroke (up) compresses the mixture. Just
at the top of this stroke an electric spark fires
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ENGINES OF WAR
the mixture, causing an explosion which drives
the piston downwards, thus making the
Third stroke (down), during which the power is
developed.
Fourth stroke (up) expels the waste products of the
explosion.
Although all of them work on this same cycle, in
which they resemble the engines of the motor-car,
there are several much-used types of aero-engine in
which the mechanical arrangement of the parts is
quite different. Of these the best known is the
famous Gnome engine which has a considerable
number of cylinders arranged around a centre like the
spokes of a wheel. The centre is in fact a case which
covers the crank, and the cylinders are placed in
relation to it just as the spokes are placed around the
hub of a wheel.
There is only one crank and all the connecting-rods
drive on to it. Owing to their position around it they
thus act in succession, giving a nice regular turning
effort.
Further, these engines differ from all others in that
the crank is a fixture while the rest of the engine
goes round, exactly the opposite of what we are
accustomed to. The engine, in fact, constitutes its
own flywheel. Rushing thus through the air, the
cylinders tend to keep themselves cool, doing away
with the need for cooling water and radiators.
Consequently engines of this type are the very
lightest known in proportion to their horse-power.
A fifty horse-power engine can be easily carried by
one man,
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ENGINES OF WAR
It would be possible to go on much longer with
this most interesting subject of engines, but having
treated the three types which are most used in
warfare, it is now time to pass on to something
else.
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CHAPTER XV
DESTROYERS
EXCEPT for the submarine the most promi-
nent craft during the war has undoubtedly
been the destroyer.
All warships are in one sense destroyers, since it is
their prime duty to destroy other ships, so why
should one particular kind of boat be given this name
specially ? Like many other of the terms which we
use it is an abbreviation, a mere remnant of a fully
descriptive title. " Torpedo Boat Destroyer " is
what these ships are called in the Navy List.
Even that full title, however, only tells us what
their original purpose was : it leaves us very much in
the dark as to the many various functions which they
perform.
The invention of the torpedo called for the con-
struction of small boats whereby the new weapon
could be used to best advantage, and so we got our
torpedo boats. They in turn called forth another
boat whose duty it was to run down and destroy
them, and in that way we get our destroyers. From
that bit of naval history we can almost see for our-
selves what the characteristics of the destroyers
must be. They have to be bigger than the torpedo
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DESTROYERS
boats, but as the latter were quite small the destroyers,
though larger, are still comparatively small craft,
latterly of about one thousand tons. Then they
have to be very fast, in order to be able to chase the
others and, finally, they need one or two guns, com-
paratively small so as not to overburden the ship
and yet large enough to dispose of anything of their
own size or smaller.
Unquestionably, their greatest feature is their
speed. They are the fastest ships afloat, rivalling
even a fairly fast train. Some of them can exceed
forty miles an hour. They are very active and
nimble, too, being able to turn in a comparatively
small circle. For warships, too, they are cheap, so
that a commander can afford to risk losing a destroyer
when he would fear to risk another vessel. For all
purposes except the actual hard-hitting they are the
most useful weapon which the commander of the
fleet possesses.
When the main fleet puts to sea a whole cloud of
these smaller craft hover round looking for sub-
marines or for the surface torpedo boats which might
try to attack the large ships under cover of darkness,
while keeping a sharp look-out, too, for mines or any
other kind of floating danger, and thus they screen
the more valuable ships.
Likewise do they convoy merchant ships some-
times, especially through waters believed to be
infested with submarines. They also sally forth on
little expeditions of their own, knowing that they
can fight any craft equally speedy and show a clean
pair of heels to any heavier ships, while by adroit
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DESTROYERS
use of their own torpedoes they may even " bag " a
cruiser or two.
They are pre-eminently the enemy of the submarine,
for the under-water boat is necessarily less active
even when it is on the surface than they are, so that
a submarine caught by a destroyer stands a very
good chance of being rammed by it, which means
that the destroyer deliberately rushes at it, using its
own bow as a ram wherewith to knock a hole in it.
Or if that be not practicable the destroyer, while
dodging the torpedo of the submarine, may plant a
single well-aimed shot into its opponent and the fight
is over. A cleverly-handled destroyer appears to
have little difficulty in avoiding the comparatively
slow torpedo, but no ship ever built could avoid a
properly aimed shell, two facts which are clearly
indicated by the very few cases in which, during the
war, a destroyer has succumbed to a submarine.
The gun of the latter, if it has one, is no match for
the guns of the destroyer.
Naval strategy and tactics, when one thinks about
them carefully, reveal a very close resemblance to
those of the football field. The destroyers are like
the forwards, quick, light and nimble, valuable
chiefly because of their ability to run swiftly and to
dodge cleverly, while the heavy, stolid backs represent
the battleships in their ability to withstand the
heavy shocks of the game. Any imaginative boy
will be able to carry this simile farther still and a
comparison of the description of the battle of Jutland
with his own knowledge of the game will reveal a
surprising parallelism.
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DESTROYERS
Thus the reader will to a very large extent be able
to see for himself the manifold uses to which these
wonderful little ships lend themselves, and he will
see that above everything else it is their speed which
counts, which fact gives us the key to their peculiar
construction.
To commence with, they are made as light as
possible. The material used is different from that of
ordinary ships, being " high-tensile " steel, a steel
into which a little more carbon than usual is intro-
duced, resulting in about 50 per cent higher tensile
strength but also involving, alas ! rather more brittle-
ness. When made of this material the whole frame-
work of the vessel can be made of lighter beams and
the covering can be of thinner plates than would be the
case if the mild steel ordinarily employed for ship-
building were used, The high-tensile steel is lighter
for a given strength and therefore a ship built of it
is lighter than it would otherwise have to be.
Besides the use of this particular material every
resource in the way of ingenuity and skill on the part
of the designers is bent towards saving weight. No
unnecessary part is ever put hi, but, on the other
hand, necessaries are skinned down to the utmost
limit consistent with safety in order to produce a
light ship. How difficult this problem is is hardly
realized until one thinks of the conditions which
prevail when a ship floats in the water. The upward
support of the water is exerted in a fairly regular way
all along the ship while the weights inside which are
pressing downward are concentrated in lumps. The
engines, for example, represent a very heavy weight
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DESTROYERS
concentrated in one fairly confined spot. Thus the
vessel has to have sufficient stiffness to resist the
action of these opposing forces which are thus
tending to break her in two. That, moreover, occurs
in the stillest water ; when the sea is rough still worse
stresses are brought to bear upon the comparatively
fragile hull, for a wave may lift each end, leaving the
middle more or less unsupported, or one may lift the
middle while the ends to a certain extent are left
overhanging. All this, too, is in addition to the
knocks and buffets caused by huge volumes of water
being flung against the ship by cross seas in the
height of a tempest. In the case of ordinary ships
where speed is not of such great importance, the
problem is simplified by the use of what is termed a
high " factor of safety," which means that the
designers calculate these forces as nearly as they can
and then make the structure amply strong enough.
In other words, care is taken to keep well on the safe
side. In a destroyer, however, there is no room for
such a margin of safety. Risks have to be taken, and
it is only the high degree of skill and experience
possessed by our ship designers which enable these
light ships to be made with, as experience, shows, a
very considerable degree of safety. They have to be
continually choosing between strength on the one
hand and lightness on the other and the way in which
they combine the two is marvellous.
The weight thus saved is used for carrying engines,
boilers and fuel. Relatively to its size, the destroyer
is about as strong as an egg-shell, but its engines are of
extraordinary power.
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DESTROYERS
The destroyers are generally organized and operate
in little groups or flotillas of perhaps twenty or so
with a small cruiser or a flotilla leader as a flagship,
on which is the officer in command of them all. There
is also usually a depot ship for each flotilla.
The flotilla leaders are what one might call super-
destroyers, about double the size of the ordinary
large destroyer, which is to say, about two thousand
tons, and capable of very high speed.
The depot ships form a kind of floating head-
quarters for their respective flotillas. They are
usually old cruisers which are specially fitted up for
the purpose, and although they are of comparatively
slow speed they can by wireless telegraphy keep in
touch with the destroyers, which can return to them
when occasion permits or demands. They carry
workshops in which small repairs can be carried out,
spare ammunition and stores of all kinds and spare
men for the crews. In fact they can look after the
smaller craft much as a mother looks after her
children, and for that reason they are sometimes
called " mother ships."
As has been said, the destroyer was originally
intended to destroy torpedo boats, but small torpedo
boats have almost gone out of existence or rather
the class have so grown in size as to have become
merged in the destroyers, which, it must be remem-
bered, are well armed with torpedoes which they
have at times used with great effect. It is not
surprising, therefore, to find that a still newer class
of ship has arisen which has been described by one
authority as " destroyer-destroyers." Officially
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DESTROYERS
known as " light armoured cruisers," not very much
is known of their details. They are, however, about
3500 tons, with 10 guns, large enough that is to dis-
pose of any destroyer which they might encounter.
Thus, to review the whole class of ships of which
we have been speaking, we may say that there are the
destroyers, all the more recent of which are about
1000 tons but diminishing as we go backward in time
to about 350 or 400 ; the flotilla leaders about twice
the size of the largest destroyers ; and the destroyer-
destroyers nearly twice as large as the flotilla leaders :
all are characterised by high speed and by guns just
large enough for the work for which they are intended.
All are armed, too, with the deadly torpedo for attack
upon larger ships than themselves.
They are essentially night-birds, much of their time
being spent stealing about with all lights out, in
pitch darkness, seeking for information or for a
chance to put a torpedo into some chance victim.
These night operations are very hazardous, but so
skilful are the young officers who have charge of
these boats that seldom do we hear of mishaps.
But although, as has been said, the torpedo boat
has almost vanished, its under-water comrade has
recently assumed a place in the first rank of import-
ance, and perhaps to us the most valuable work of all
done by the destroyer is that of hunting down and
sinking these modern pirates.
190
CHAPTER XVI
BATTLESHIPS
PERHAPS the greatest war invention of
modern times was the British battleship
Dreadnought.
Of course, there have been battleships for centuries.
In history we read of fleets consisting of so many
" ships of the line " or in other words " line-of-
battle " ships, meaning ships which were considered
capable of taking their place in " line of battle," as
distinguished from " frigates " which correspond to
the modern " cruiser."
The " line-of-battle " ships were stout and strong
with plenty of guns. They went into the thick of the
fight, since they were capable of giving and receiving
hard blows, while the lighter frigates hovered around
seeking an opening to use their higher speed to cut
off stragglers or to prey upon merchant ships.
Although so different in form and material that a
sailor of the old days, could he revisit the earth,
would not recognize them, the battleships of to-day
are the real descendants of the " line-of-battle " ships
of those times. They are stout and strong, with the
heaviest guns, capable of giving and taking the
hardest knocks, and it is they who form the backbone
of the fleet. As we saw in the accounts of the battle
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BATTLESHIPS
of Jutland, the German Fleet tackled our cruisers and
lighter vessels but discreetly withdrew when the
battleships came up.
Looked at in another way, we may say that a
battleship is a floating fortress. Its speed is not
great, when compared with other ships, but it is
constructed to carry enormous guns. It is also
armoured with steel plates of great thickness and of
special hardness placed upon the outside of the hull
so as to cover its vital parts and protect them from
the shells of the enemy. Its chief function, we may
say, is to carry its guns : to enable it to do this with
safety, it is armoured : and to enable it to get to
grips with its enemies it has engines and boilers.
Those are the three features of greatest importance in
a battleship, its guns, its armour and its engines. All
else is of minor importance.
It is strange to think how short a time the iron or
steel ship has been with us. In the American Civil
War, for instance, only about sixty years ago, the
battleships were made of wood. It was during that
war that Ericcson thought of the idea of putting iron
plates to protect the sides of a ship from the hostile
shots, and from that improvised armouring of a
wooden ship has arisen the iron-clad or, more
correctly, steel-clad monsters of to-day.
It is just about fifty years ago since the last iron-
clad wooden battleship was launched for the British
Navy. Her name was Repulse, and she took the
water in 1868. With a tonnage of 6190 and a horse-
power of 3350, she had a speed of 12 knots. Her
armouring of iron was in parts 4| inches and in
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BATTLESHIPS
other parts 6 inches thick, while she carried 20 guns
of sizes which to-day would seem mere toys. If all
her guns were discharged together she would throw
a total weight of 2160 Ibs. of projectiles.
Now, for comparison, let us take a modern battle-
ship, the Orion, for example. The tonnage is 22,680,
the horse-power 27,000.
She is more than twice the length of the older
ship and is armoured with steel 12 inches thick. Her
10 large guns, each 13| inches in diameter, if fired
together (as I once heard them, like thunder, though
10 miles away) throw a weight of 12,500 Ibs.
From this we see the wonderful growth in size,
speed and in hitting power during the comparatively
short period of fifty years. But there is a more
striking comparison still.
The Repulse's guns threw 2160 Ibs. and the Orion's
throw 12,500. But that takes no account of the
energy with which the weight is thrown. A tennis
ball hit hard, might really contain more energy and
do more damage to anything it hit than a cricket ball
thrown gently, which illustrates the fact that in
comparing the power of guns we need to consider
something more than the mere weight of the pro-
jectiles. To arrive at a real comparison we take the
weight of the projectiles in tons and multiply it by
the speed at which they leave the guns in feet per
second. And we call the answer so many " foot-
tons."
Now the energy of the Repulse thus reckoned
comes to just under 30,000 ; that of the Orion to
just under 690,000. The Orion can hit twenty-three
N 193
BATTLESHIPS
times as hard as could its forerunner of only fifty
years ago.
Since the Repulse all our battleships have been
built of wrought iron or mild steel. Speaking
generally, there was a steady development in size and
horse-power and in speed until 1906, in which year
there was launched the world-famous H.M.S. Dread-
nought. Previously no battleship had been faster
than 19 knots : she was designed for 21 knots.
Her tonnage was 17,900, exceeding by more than
1000 tons anything that had gone before. But
the great change was in the guns. Pre-Dreadnoughts
had, or one ought to say " have " for there are still
many in existence, four of the biggest guns, a number
of medium-sized guns and a still larger number of
smallish guns intended for the purpose of keeping off
torpedo craft and such small fry.
At one stroke Lord Fisher, who was then the First
Sea Lord of the British Admiralty, changed all this.
He swept all the medium-sized guns away and gave
this new ship TEN of the largest guns then in use.
The advent of this ship startled the whole naval
world, for it was seen at once by all those able to
judge that there was a vessel which might be expected
to sink with ease any other ship afloat. The onslaught
from those ten guns would be more than any other
ship could stand. So other powers set to work to
copy more or less exactly, while Great Britain quickly
built more like her. So important was this new
invention that very soon the strength of the naval
powers began to be reckoned entirely on the number
of Dreadnoughts they possessed, the older ships being
194
BATTLESHIPS
left out of account as though they did not make any
difference one way or the other.
But Great Britain was not content with the
Dreadnought, for each succeeding ship or set of ships
was improved until, only four years later, there was
launched the Orion already referred to, nearly 5000
tons bigger, with 2500 more horse-power, and with
13^-inch guns instead of 12-inch. The Orion and her
sisters are often spoken of as super-Dreadnoughts.
The Dreadnoughts as a class are often referred to
as " all-big-gun " ships, since that is the feature
which most distinguishes them from those which
went before.
These large guns are mounted in turrets as they
are called. We might describe these as turn-tables
with a cover over something like a small gas-holder.
There are usually two guns in each turret, although
there are a few ships whose turrets have three in
each.
The turrets seem to be standing on the deck of the
ship and it is by turning them round that the guns
are trained or pointed at their target.
The original Dreadnought had one turret in front
and two behind, all on the centre-line of the ship,
and two more, one each side, amidships. In late
vessels all five turrets are on the centre-line. Thus
the Dreadnought can fire six guns ahead, eight astern
and eight to either side, while the newer ships can
fire four ahead, four astern and all ten on either side.
There are other battleships with even more guns
than these, such as the U.S.A. ship Wyoming, with
twelve 12-inch guns, but the British Navy seems to
BATTLESHIPS
prefer to stick to the original number of ten. The
reason for this is that every such ship is a compromise
between three alternatives.
The three great features have already been pointed
out, namely, the guns, the armour and the propelling
machinery. Either of these can be increased at the
cost of one or both of the others, but all cannot be
increased without sinking the ship, unless indeed, the
ship be made larger and then other considerations
crop up.
And that brings us to another class of ship often
ranked among the battleships. These remarkable
vessels are also termed cruisers and the fashion seems
to have established itself of combining the two names
and calling them battle-cruisers. They gave a fine
account of themselves during the war.
The first three of these, of which the Invincible is
usually taken as the type, made its appearance the
year after the Dreadnought, and like the latter were
the offspring of the fertile brain of Lord Fisher. The
Invincible was about the same size as the Dreadnought,
but had nearly twice the horse-power (41,000), which
enabled it to attain an actual speed of nearly six knots
more, namely, 28-6.
For guns it had eight of the same large weapons,
and it was armoured with 7-inch steel armour-plates
instead of 11 -inch.
Thus we see illustrated what has just been said,
less guns and thinner armour, to allow for more
engine power and higher speed. Or, to put it the
other way, we observe how higher speed was attained
at the expense of the guns and the armour.
196
BATTLESHIPS
But just as the Dreadnought was followed by other
still greater improvements in the same direction we
get, in 1910, the famous ship Lion, a vessel not
unknown to the Germans, a " super-Invincible."
This ship has a tonnage of over 26,000 and 70,000
horse-power. It was designed to do 28 knots.
We saw the use of these ships in the Jutland battle,
when, using their high speed, they attacked the
German battleships and kept them engaged while
the slower battleships came up. Though they
suffered severe losses, which probably the more
heavily armoured battleships would have escaped,
they held the Germans so that it was only the failing
light which saved them from utter destruction.
Another example was the way in which they
hunted down Von Spec and his squadron off the
Falklands, when they caught the Germans because
of their higher speed and then sank them by means
of their heavier guns with practically no loss to
themselves.
We saw them again in the Heligoland battle,
coming up to the assistance of the lighter vessels just
in the nick of time and scattering the enemy like so
much chaff.
A fact little known to most people and productive
of much surprise is that these battleships and cruisers
are not such very large vessels, when compared with
those of the merchant service. The Lion is 660 feet
long and 86 feet wide, the Aquitania is 930 feet long
and 98 feet wide, and the Olympic is 882 feet long
and 92 feet wide.
The mighty Orion makes a poorer showing still in
197
BATTLESHIPS
point of size, since she is only 545 feet long and 88 feet
wide little over half the length of the Aquitania.
It is difficult to compare the tonnage of a warship
with that of a merchant ship, since they are not
measured in the same way. The former is the " dis-
placement " or actual weight of water displaced : in
other words the precise weight of the vessel in tons of
2240 Ibs.
The tonnage of a merchant ship, however, has
nothing to do with weight but is based upon capacity
and is arrived at by a purely arbitrary rule, thus :
all the enclosed space in the ship is measured in cubic
feet and the total is divided by one hundred. That
gives the gross tonnage. To arrive at the net tonnage
the space occupied by the engines and all other space
necessary for the working of the ship is excluded.
Originally the tonnage of a merchant ship was the
number of " tuns " of wine which it could carry.
Thus, you see, comparing the tonnage of a war-
ship with that of a merchant ship is somewhat like
comparing a pound with a bushel. Net registered
tonnage is generally considerably less than the
displacement tonnage of the same ship, so that a
warship is usually less than a merchant ship of the
same nominal number of tons.
And now let us turn to some of the internal
arrangements of these wonderful ships, more par-
ticularly to the means for working the guns.
Each turret is placed over the top of what we might
call a well, running right down deep into the inside
of the ship. At the bottom of this well is the
magazine, where the shells are stored and also the
198
BATTLESHIPS
cartridges containing the explosive which drives the
shell from the gun.
Underneath the turret, forming a kind of base-
ment to it, is a chamber called the working chamber,
and up to it the shells and cartridges pass by means of
lifts. For safety's sake only a small quantity of
explosives is kept here at any one time, but it is
from here that the guns overhead are fed. Shells and
cartridges alike pass up as required by means of hoists
right to the guns. Indeed, the hoists are ingeniously
contrived so that in whatever position a gun may be
the hoist stops exactly opposite the breech, or
opening at the back of the gun through which it is
loaded. Then a mechanical rammer drives the shell
or cartridge into its place in the gun.
The hoists are worked by hydraulic power or
electricity, and in most cases by both, arrangements
being made so that either can be used at will, thus
serving as alternatives in case either should get out of
order.
The turrets themselves are also turned by power.
Indeed, so heavy are the weights involved that only
by the use of carefully designed machinery is the
operation of such great weapons made possible. A
single shell of the 13-5-inch gun weighs 1250 Ibs.
Around each turret there is placed a wall of thick
armour plate as high as it is possible to make it
without interfering with the movement of the guns.
This is called the barbette armour and the space
enclosed by it, in which the turret stands, is called a
barbette, an old fortification term meaning a place
behind a rampart.
199
BATTLESHIPS
The turret is covered over, as has already been
remarked, by a steel hood, so that altogether the guns
and their crews are about as well protected as it is
possible to be.
That all this means a considerable burden upon
the ship is shown by the fact that a pair of 12 -inch
guns with their turret and barbette armour will
weigh something like 600 tons, and if there be five
of them that means 3000 tons in all.
Down below in the magazine there are lifting
appliances whereby the shells can be readily picked up
and run to the hoist. Moreover, there is elaborate
machinery for keeping them cool. Our allies the
French had, years ago, several bad accidents through
the explosives going off spontaneously in their ships,
and this is quite likely to happen if the magazines
become too hot. So refrigerating apparatus is
installed similar to that employed in meat-carrying
ships, which provides a constant flow of cool air into
the magazines.
The ships also are subdivided to the greatest
possible extent consistent with efficient working, so
that in the event of a collision or a torpedo making
a hole below water the ship may not sink. As far as
possible the divisions or bulkheads are made to run
right from top to bottom without any openings, but
that obviously is a very inconvenient arrangement,
so in many places there have to be doorways through
them, leading from one part of the ship to another.
In such cases these are closed by water-tight doors,
which can be shut before the ship goes into action or
into any dangerous region.
BATTLESHIPS
The engines of these vessels are now always
turbines. This type of engine has many advantages
over the older type, in which certain parts move to
and fro, that motion being changed by cranks into
a round and round action. For one thing, they are
lighter for a given power, so that more power can be
put into a ship without adding to the weight. That
means higher speed. Then there is less to get out of
order. Anyone who has been into a ship's engine
room where to and fro or reciprocating engines are
at work will realize this, for there is a maze of rods
and cranks all moving together, and many parts
which need to be oiled while in motion and which
would get hot and tight if they were not carefully
looked after. All this in an enclosed space with
possibly an uncomfortable motion of the whole ship
used to make the engineer's life at sea a very hazard-
ous and unhappy one.
But the turbine is entirely enclosed. There is
nothing to be seen moving at all. Indeed, there is
only one moving part, and that is coupled directly
to the propeller-shaft, so that nothing could possibly
be simpler.
201
CHAPTER XVII
HOW A WARSHIP IS BUILT
WHEN it is decided to build a certain ship,
the first thing to be done is to draw
it on paper. The Admiralties of the
world, and also the great shipbuilders, have each
their own chief designer installed in a big, light, quiet
office fitted with large strong, flat tables at which
work a number of draughtsmen.
The naval authorities tell the " chief " in general
terms what they want the ship to be capable of, and
he determines its size and form. Then the draughts-
men work out his ideas on paper, themselves deciding
upon the minor details, until they have produced
exact representations of the ship which is to be.
Some draughtsmen deal with the actual hull of the
ship, while others design the various fittings and
minor details, all working, of course, under the con-
stant supervision of the chief.
In this connection one may perhaps allude to a
matter which the general public often seems to mis-
understand the work and functions of a draughts-
man. I have heard people say of a boy that he is
good at drawing so they think of making a draughts-
man of him. Now the point is that the actual draw-
ing is perhaps the least important part of a draughts.-
HOW A WARSHIP IS BUILT
man's work. He has to know what to draw. He is
given just a rough idea of something and from that
he has to produce a perfect design, bearing in mind
.that the thing to be made must well fulfil its purpose,
must be easy and cheap to construct, must be strong
enough yet not too heavy, must be made of the most
suitable material and so on. He has to possess a
good deal of the knowledge of the skilled workman,
he has to be something of a scientist and a good
mathematician in addition to his ability to make
neat and accurate drawings. So, you see, these men
whose minds conceive the details of our great ships
are men of long training and experience, with far
greater knowledge and skill than we sometimes give
them credit for.
Anyway, there they stand, each at his own table,
bending over his own drawing-board, each doing his
own particular share towards producing the perfect
ship.
But when all is said and done, there are limitations
to the cleverness of the cleverest among us, so the
next step, after the draughtsmen have done their
best, is to test what they have done by experiment.
Years ago a certain Mr. William Froude interested
himself in the question of the best shapes for ships,
and he found that by making an exact model of a
ship and then drawing that model through water it
was possible to foretell just how that ship would
behave. He built himself a tank for the purpose of
these experiments at Torquay, where he lived, and
by its aid he added a very important chapter to the
science of shipbuilding.
203
HOW A WARSHIP IS BUILT
Nowadays the Admiralty have a large and well-
fitted tank at Portsmouth, the United States Navy
have one at Washington, private shipbuilders have
the use of a national tank at Bushey, near London,
while several of the large firms have tanks of their
own.
The national tank at Bushey, by the way, was
given to the nation by Mr. Yarrow, a famous ship-
builder, in memory of Mr. Froude, it being called the
" William Froude Tank " in recognition of the great
work done by him.
Now these tanks may be described as rather elon-
gated swimming-baths. Such a structure is generally
a little narrower than the average bath, but it is
longer and much deeper.
At one end there are miniature docks in which the
models float when not in use, while at the other there
is a sloping beach upon which the waves caused by
the models expend their energy harmlessly.
Along each side there runs a rail upon which are
supported the ends of a travelling bridge. Driven
by electric motors, this bridge can run to and fro
from end to end of the tank, and its purpose is to
drag the models through the water.
Carried upon the bridge is a platform which bears
a number of instruments, chief among which is a
self-recording dynamometer.
Now a dynamometer is an instrument for measur-
ing the force of a " pull," and when we call it self-
recording we mean that it automatically takes a
record of a series of pulls or of a varying pull. In
this case there projects below the bridge a lever, to
204
HOW A WARSHIP IS BUILT
the end of which the model under test is attached.
As the bridge rushes along it pulls the model through
the water by means of this lever, and the force which
is expended in doing so is recorded in the form of a
wavy line upon a sheet of ruled paper.
If the model slips through the water very easily
there is little pull upon the lever and the line drawn
by the pen of the instrument remains low down upon
the chart. If, however, much power is needed and
the pull is a strong one the pen moves and the line
rises towards the top of the paper. Any change,
whether increase or decrease, is thus shown by the
rise or fall of the ink line.
One model can be thus tried at various speeds and
its behaviour noted under different conditions.
Other matters can be investigated too, such as
whether or not the bow rises in the water or falls
when the boat is in motion, also how much such rise
or fall may amount to.
The suitability of a certain shape of vessel, more-
over, can to a certain extent be seen by observing
the commotion which it makes in the water. Every-
one has noticed the way in which a ship throws up a
wave at its bows, and that bow- wave, as it is termed,
represents so much energy being wasted. The power
of the engines is absorbed to a certain extent in making
that wave. It is impossible to make anything which
when forced through the water will not make some
wave, but certain forms cause less of it than others,
and the designer of a ship seeks to find that form
which will make the smallest bow- wave.
In like manner the eddies which a ship leaves in
205
HOW A WARSHIP IS BUILT
its wake are the result of wasted energy, and the
ship must be so shaped that they too will be reduced
to a minimum.
Shipbuilders find that there are three things which
retard a ship's movement : skin friction, or friction
between the water and the sides of the ship ; wave
making at the bow and eddy making at the stern.
The first depends largely upon the smoothness of the
ship's surface, the second and third depend upon its
shape. If a model behaves badly in the tank the
fault may be either too much wave making or too
much eddy making, and which of these it is the
dynamometer does not of course tell. In many cases
the experienced eye of the tank officials furnishes the
clue to the trouble, but in some cases a cinemato-
graph is used to make a complete series of photo-
graphs of the model and the water around it as it
rushes from end to end. These can then be studied
in conjunction with the chart and the cause of the
fault discovered.
The real aim, it is obvious, of all these tank experi-
ments is to find out the lowest horse-power necessary
to drive the ship, or the best form of ship to get the
highest speed out of a given horse-power.
The cost of keeping up these large tanks and
making the models and conducting the experiments
is very great, for not only are the premises very large
(I know one in which the water alone cost nearly a
hundred pounds) but a highly skilled staff is necessary.
The saving effected in the cost of ships and the superior
efficiency of the ships makes it well worth while
however.
206
HOW A WARSHIP IS BUILT
There is still one other point about this matter
which will possibly be puzzling the observant reader.
What are the models made of and how are they made ?
They are made of paraffin wax, and a very important
department of the experimental tank is that where
the models are formed.
First of all a rough mould is fashioned by hand in
modelling clay and into this is poured melted wax,
the result being a very rough model of the ship. This
is then placed in the model-making machine.
Those of my readers who are familiar with an
engineer's shop will know what a planing machine is
like, and from that they can form an idea of the
general structure of this remarkable tool. There is,
first of all, a travelling table which, as the machine
works, travels to and fro. Spanning this table is a
beam which carries on its under side two revolving
cutters, so that as the table passes beneath them the
cutters can operate upon anything placed upon the
table.
Another part of the machine is a board upon which
is placed the drawing showing the external shape of
the proposed ship, and working over this board is a
pointer connected by a system of rods and levers to
the cutters just mentioned. The rough block of wax,
then, having been placed upon the table and the to
and fro motion set going, the attendant guides the
pointer along the lines of the drawing, and as he does
so the cutters so move as to carve away the soft wax
into the precise shape of the model.
A little smoothing by hand is all that is necessary
to complete the conversion of the rough piece of wax
207
HOW A WARSHIP IS BUILT
into a perfect model. It is then placed in the water
and ballasted with little bags of shot until it floats at
just the correct depth, and finally a light wooden
frame is fitted to it for the purpose of making the
connection to the lever by which it is pulled along.
Thus, after much thought and experiment, the
designs for a new ship are completed. Tracings are
then made of them on semi-transparent paper or
cloth, which tracings are then used as " negatives,"
from which a number of photographic prints are
made, just as the amateur photographer makes prints
from his negatives. At least that is how they used to
be done, in a huge printing frame, but nowadays a
machine is more often employed which passes the
tracing or negative with a piece of photographic
paper behind it slowly past an electric light, thus
doing the work more quickly and more conveniently,
for the drawings of ships are often very long and would
either require an enormous frame or else would have
to be made in pieces and joined together.
The prints are finally passed out to the works to be
translated in terms of iron, steel and wood.
Perhaps the most important part of a shipyard is
the mould loft, a large apartment on the floor of
which the ship is drawn out full size. Then from
these full-size drawings moulds or templets are made
of wood or soft metal, showing the exact size and
shape of the various parts. The moulds or templets
go thence to the workshops, where the bars and plates
of steel are cut to the right shape and perforated with
holes, and some of the pieces are there joined together
with rivets.
THE TRIPOD MAST.
stability and freedo
tripod mast of a warship. These masts have greater
rom vibration than others. They are used for obsenation and
leg of th
lity and freedom from vi
ange-finding, and have a fighting-top on which guns of small calibre are mounted.
Here is shown a sailor carrying a wounded comrade.
HOW A WARSHIP IS BUILT
From the workshops the various pieces or parts go
to the yard where the slip is on which the vessel is
being built. This slip is by the water's edge, con-
veniently placed with a view to the fact that later
on the great structure, weighing possibly thousands
of tons, has got to slide down into the water.
Where the keel of the ship is to go a row of timber
blocks is placed a few feet apart, and upon these
blocks the plates of steel which form the lowest part
of the ship are laid. Upon them are laid other parts,
and upon them others, the joints being made by
riveting. Thus the great ship grows from the keel
upwards. As she gets bigger and bigger there comes
the danger of her tipping over, and that is provided
against by the use of props or shores along both sides.
By the time the hull is ready for launching it is
often of great weight, all of which is borne upon the
wooden blocks underneath the keel. Consequently,
if the ground be not good, piles have to be driven in
or concrete foundations laid to enable the huge mass
of the ship to be supported. For this reason a large
vessel cannot be built any where 1but only on a properly
prepared " slip," and it is the possession of a large
number of such places which enables Great Britain
to build so many ships at once.
Along each side of the slip there is usually a row of
tall masts with a beam projecting out sideways near
the top of each, forming cranes by which the heavier
parts can be hoisted into position.
In other yards, again, there is a tall iron structure
called a gantry along each side of the slip, while
travelling cranes span across from one to the other
o 209
HOW A WARSHIP IS BUILT
over where the growing ship lies. These travelling
cranes, worked by electricity, permit heavy weights
to be handled with ease and safety. Other subsidiary
cranes, meanwhile, carry the heavy hydraulic rivet-
ing machines by which riveting is done.
Much riveting is done by hand, men working
together in squads of four. Of these one, often quite
a boy, heats the rivets in a small furnace, after which
he throws them one by one to man number two, who
inserts each as he receives it in its proper hole and
holds it there with a big heavy hammer or else a tool
called a " dolly." Number two is called the " holder-
up," since he holds the rivet up in its place while
the remaining two hammer it over with alternate
blows of their hammers.
In many cases, however, the two last described
men give place to one, who is armed with a tool in
shape much like a pistol and operated by compressed
air obtained through a flexible tube. When he presses
a trigger a little hammer inside the " pistol " gives a
rapid series of blows to the rivet, completing the job
more quickly than the two men can do with hand
hammers.
A third way of doing this operation so important
in the building of a ship is by the hydraulic machine
suspended from the cranes. To the casual onlooker
this has the notable feature of being silent, whereas
riveting by hand and still more by a pistol hammer
is terribly noisy. The reason for this is that the
hydraulic riveter does not hammer at all, but, like
a huge mechanical hand, it takes the rivet between
finger and thumb and just squeezes it down.
HOW A WARSHIP IS BUILT
One strange result of all this hammering in of rivets
is that every ship by the time it leaves the slip has
become a huge magnet, with somewhat disconcerting
effects upon its own compasses, but of that more
later on.
Thus the great ship grows, being made piece by
piece in the workshops to the shapes indicated from
the mould loft and put together and riveted on the
slip, until finally in due time it is ready to take its
first journey.
The launching of a big ship always strikes me as
about the boldest and most daring thing which is
ever done in the course of industry. For the huge
structure, naturally top-heavy, weighing hundreds
or thousands of tons, is just allowed to slide at its
own sweet will. From the moment it starts until it
is well in the water it is in charge of itself, so to speak,
and if anything were to go wrong no power on earth
could stop it once it had got a start.
That nothing ever does go wrong, or scarcely ever
at all events, is due to the care with which all prepara-
tions are made before that critical moment when the
ship is let loose and to the skill and experience of
those in charge.
As the hull reaches that degree of completion when
it can safely be put in the water, strong wooden
structures termed launching ways are constructed
one on each side of her. These really act like huge
rails upon which in due course there will slide a
gigantic toboggan. Tremendously solid and strong
they have to be, as they have each to carry half the
total weight of the ship.
211
HOW A WARSHIP IS BUILT
Under each side of the ship and upon the launching
ways there is built a timber framework capable of
raising the ship bodily off the blocks upon which
until now it has reposed. These two frames, being
connected together by chains passing beneath the
keel, constitute what is called the cradle, the " to-
boggan " which is to slide down the ways, bearing
the ship upon it.
It is easy to see that being top-heavy something
must be done to give the ship support before the
shores on either side can be taken away, and it is
equally clear that these latter must be removed before
she can slide down to the water. Neither would it
do to let the vessel slide upon her own plates, so we
see that the cradle fulfils a twofold purpose, first
enabling the ship to reach the water without ripping
holes in her own plates, and secondly giving it the
necessary side support to prevent it from toppling
over on the way.
When all is ready, but a short time before the hour
appointed for the launch, a curious operation is per-
formed. Between the main part of the cradle and
the part which actually slides upon the ways wedges
are inserted, hundreds of them, and they are all
driven in simultaneously. Their purpose is to make
the cradle slightly higher and so to lift the ship off
the blocks upon which it was built. If they were
driven in one at a time each would only dig its way
into the timber and nothing else would happen, but
being driven all together a most powerful lifting
action is produced which actually raises the mighty
ship. So hundreds of men stand, each with his
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HOW A WARSHIP IS BUILT
hammer ready to strike a wedge, while the foreman
stands by with a gong. At a stroke on the gong the
hundreds of hammers strike as one, and so the ship
is raised off the blocks, which can then be removed,
to facilitate which they too are built of wedge-shaped
pieces which can easily be knocked apart. The
shores, too, have ceased to serve any useful purpose
and can be taken away until at last all shores and
all blocks are gone and the vessel rests upon the
cradle only. Meanwhile tons of grease have been
put on the ways, and the ship, urged by its own weight,
is straining to get down the greasy slope into the
element for which all along it has been intended. At
this stage the only thing which restrains it is a kind
of trigger arrangement on either side which locks the
cradle in its place. In some yards elaborate mechani-
cal catches controlled by electricity are used for this,
but in many the old device of " dog shores " is still
used. These are simply two stout wood props which
fit between a projection on the ways and one on the
cradle, there being one dog shore on either side. Just
over each dog shore there hangs a weight.
The person who performs the ceremony cuts the
cord which holds the weights, the weights fall, the
dog shores are knocked away, and the ship is free.
Slowly at first, but gathering speed every moment,
she moves majestically downwards into the water,
being ultimately brought to rest by means of
chains.
Whether done by the simple dodge of cutting a
cord or by the more refined method of pressing an
electric push, the launching is generally preceded by
213
HOW A WARSHIP IS BUILT
the breaking of a bottle of wine against the bows and
the pronouncement of the vessel's name.
Once safely afloat, the vessel is towed away and
berthed alongside a wharf whereon are cranes and
other machines which lightly drop on board of her
the massive turbines and boilers which in time will
propel her, and the guns with which she will fight.
All the multitudinous little finishing touches are here
put into her until at last she sallies forth on her trial
trips to show what she is capable of, after which
follow trials of her guns, and then she takes her place
in the fleet.
Thus, briefly sketched, we see the history of the
warship from her inception in the minds of her
designers till she is ready to meet the foe.
214
CHAPTER XVIII
THE TORPEDO
IN parts of South America there lives a little
fish, which, if you touch its nose, gives you a
severe electric shock. The natives call it the
" torpedo." When an artificial fish came to be
invented, capable of giving a very nasty shock to
anyone touching its snout, that name was bestowed
upon it too.
Even more than the submarine, the torpedo
resembles a fish with its graceful outlines and its fins
and tail, the chief difference being that the tail of the
torpedo carries a couple of little rotating propellers.
Looked at another way we may say that the
torpedo is an automatic submarine. As a matter
of fact, we all know it best as the weapon of the
submarine.
It was originally invented by an Austrian who took
it to a Mr. Whitehead, an Englishman who then had
an engineering works at Fiume. This gentleman
took up the idea and developed it into the White-
head torpedo, which is to-day used by half the navies
in the world, the rest using something very similar.
It is curious to note that the German variety is called
215
THE TORPEDO
the Schwartzkopf, the meaning of which is " black-
head."
The smooth, steel, fish-like body consists of two
separate parts, which can be detached from each
other. The front part called the " head " is made in
two kinds, the war-head and the peace-head. The
former contains a large quantity of explosive and the
mechanism for firing it on coming into contact with
any hard body. It is only used in actual warfare.
The peace-head is precisely the same shape and
weight as the other but is quite harmless, so that when
it is fitted to the torpedo the latter can be handled
with perfect safety, a valuable feature during the
frequent exercises through which our sailors go in
their efforts to attain perfection in the use and
handling of these valuable weapons.
So much for the head. The body of the torpedo
contains a beautiful little engine precisely similar
to a steam-engine but on a small scale, which is
driven by compressed air, a store of which is carried
in a compartment provided for the purpose.
Then there is an automatic steering apparatus
controlled by a gyroscope, the purpose of which is
to keep the torpedo steered in precisely that direction
in which it is started. If any outside force, such as
current or tide, deflects it from its path the gyro-
scope, acting through a rudder at the tail, brings it
back again.
Like the submarine, moreover, it has rudders which
can steer it upwards or downwards and these again
are controlled automatically so that having been set
to travel at a certain depth the torpedo can be
216
THE TORPEDO
launched into the water with the practical certainty
that it will descend to that depth and then main-
tain it.
This remarkable result is attained by the use of
two devices acting hi combination, namely, a hydro-
static valve and a pendulum. Either of these alone
would set the thing going by leaps and bounds, at
one time above the required depth and at another
equally below it, and so on alternately. The hydro-
static valve consists of a flexible diaphragm, one side
of which is in contact with the water outside, so that
since the pressure increases with increasing depth,
it is bent inwards more or less as the depth varies.
This deflection is made to control the horizontal
rudders. Suppose that things are adjusted for the
rudders to steer the torpedo horizontally when at a
depth of ten feet : if it descends to twelve feet the
increased deflection of the diaphragm will so change
the rudders that they will tend to steer slightly up-
wards : if, on the other hand, it rises to eight feet the
contrary will happen, with the result that it will
descend. As has been said already, this alone would
result in a continually undulating course, so the
pendulum is introduced to check the too decided
changes in direction and so produce a practically
straight course.
There is an interesting feature, too, about the
propeller. It is " twin " but not, as in ships, two
screws side by side. Instead, they are both set upon
one shaft or rather upon two concentric shafts, like
the two hands of a clock. The hour-hand of a clock
is on one shaft, a solid one, which itself turns inside
217
THE TORPEDO
the shaft of the minute hand, which is hollow. The
propellers of the torpedo are likewise, one on a
tubular shaft and the other on a solid shaft inside it.
These two shafts turn in opposite directions, but
since the two propellers are made opposite " hands "
they both equally push the torpedo along. The
reason for this arrangement is that without it the
action of a single propeller would tend to turn the
torpedo over and over. Instead of the torpedo
turning the propeller the propeller would to some
extent turn the torpedo.
The range of the torpedo depends, clearly, upon the
quantity of compressed air which it is able to carry
and that is limited by certain practical considerations.
One of these is the space required to store it, and a very
ingenious method has been invented whereby the
limited supply is eked out so that in effect its quantity
is increased. As the air is used up the pressure in the
air-chamber naturally falls and when that has gone
on to a certain extent chemicals come into action
which generate heat, whereby the remaining air is
raised in temperature. This, of course, increases
the volume of air and the result is just the same
as if a greater quantity were carried to commence
with.
The explosion is brought about by the pressing in
of a pin which normally projects from the nose or
point of the torpedo, and it would be very easy to
knock this accidentally, causing a premature explosion,
were not precautions taken to prevent it. These
take the form of a little fan which is turned by the
water as the torpedo proceeds through it. The firing-
218
THE TORPEDO
pin is locked by means of a screw so that it cannot be
operated until it has been released by the with-
drawal of the screw and that can only be done by the
fan. Thus, while on the submarine or whatever ship
carries it, the torpedo cannot be fired : it only
becomes capable of explosion after it has passed
through the water for a certain distance, far enough,
that is, for the fan to have undone the screw. Thus
the maximum of safety is combined with the maxi-
mum of sensitiveness when the object aimed at is
struck.
There are other forms of torpedo which although
little used are by no means lacking in interest. There
is the Brennan, for example, at one time much
favoured in the British Navy. Its propellers were
operated from the shore, by the pulling of two very
flexible steel wires. The effect was much as if the
thing were driven by reins, as a horse is driven. On
shore was a powerful engine with two large drums on
which the wires could be wound and by which they
could be drawn in at a very high speed. By pulling
one more than the other the torpedo could be steered
and it is said that such a torpedo could be made to
follow a ship through complicated evolutions and
fairly hunt it down, finally overtaking and striking
it.
The purpose of such weapons was clearly to defend
a port or roadstead against enemy craft which might
try to rush in. It needed to be controlled by some-
one perched upon an eminence of some sort from which
he could watch its course and guide it as might be
necessary.
219
THE TORPEDO
Compare this with the ease with which the White-
head torpedo is just slipped into the water and then
left to itself. A submarine has in its bows either one
or two tubes just large enough to hold the torpedo
easily. At the front is a flap door which is kept
closed while the torpedo is slipped into its place.
Then the similar door at the rear of the tube is
closed after which the front one can be opened.
Water of course flows in and surrounds the torpedo
when this takes place and a little push from some
compressed air sends it floating out. As it emerges
from the tube the engines are set going automati-
cally and likewise the gyroscope which steers it,
after which it continues to proceed in a straight
line, soon seeking and maintaining the desired
depth.
Other vessels besides submarines have submerged
torpedo-tubes like these, but others again have tubes
of a different kind. These are fixed on the deck and
have the advantage that they can be pointed in any
direction almost like a gun, whereas the others are
either fixed rigidly in the vessel or are only slightly
movable. In the case of these other tubes the
torpedo is shot over the side of the ship, off which
it leaps into the water somewhat like a man
diving.
One other kind of steerable torpedo may be men-
tioned because of its ingenuity, although so far as is
known it is not in actual use. It is called the Armorl,
a compound of the names of its inventors, Messrs.
Armstrong and Orling. It is controlled by wireless
telegraphy in a very simple but effective manner.
THE TORPEDO
The rudder which steers it is connected to a small
crank in such a way that as the crank revolves it
turns the " helm " first to one side and then to the
other. Suppose that, to commence with, the rudder
is straight : a quarter of a revolution of the crank
sets it to one side, say, the right: another quarter
sets it straight again : a third quarter sets it to the
left : and so on. The crank is turned by a wound-up
spring, the effect of which is, however, normally held
in check by a catch. When a wireless impulse comes
along the catch is lifted for a moment, the crank slips
round a quarter of a turn and the rudder is moved
accordingly. Every impulse changes the position of
the rudder and by sending suitable series of im-
pulses it can be set as desired and changed at any
moment.
A difficulty with all these guided torpedoes is that
they must carry some indication whereby their place
at any moment will be made visible to the man in
control. A little mast and flag would do, for example,
but it would be a fair mark for the enemy's guns and
being shot away would leave the torpedo uncon-
trollable. The same objection seems to apply to the
wireless antenna which this last type must carry with
which to receive their guiding impulses, but that can
be made light and almost invisible. It is when the
thing is clearly visible that the danger arises, and, of
course, to serve its purpose it must be visible. The
way in which this difficulty was overcome by Messrs.
Armstrong and Orling is a beautiful example of
ingenuity. They cause a jet of water to be blown
upwards by compressed air, something like the
THE TORPEDO
spouting of a whale, so familiar in books of natural
history. That forms a mast which is clearly
visible, yet the enemy may blaze away at it to
their heart's content without damaging it in the
least.
222
CHAPTER XIX
WHAT A SUBMARINE IS LIKE
THE precise details of the submarines of our
own navy or of any other for that matter
are wrapped in mystery. Those who might
tell do not know and those who know must not tell.
True, there have been fully descriptive articles in
many books and magazines, but it may be safely
asserted that those descriptions are nothing more
than what this chapter avowedly is, reflections by
the authors on what such a craft must be like, more
or less. It is just as well that this should be clearly
understood, and the following description does not
claim to be any more than that.
Just as an aeroplane follows the general design of
a bird of the swallow type, which soars without
flapping its wings, so the submarine necessarily
follows much the lines of a fish. It has fins which
help to guide it, it has rudders which compare with
the fish's tail, and while it cannot use either fins or
tail to push itself along as the fishes do, it has one or
more propellers which serve that purpose admirably.
It is rather remarkable that, while we often
imitate nature very closely, there is one very im-
portant mechanical feature which almost invariably
Distinguishes man-made schemes from natural ones
223
WHAT A SUBMARINE IS LIKE
that is, that man uses rotary motion for many
purposes whereas nature practically never does. To be
perfectly honest, the natural mechanisms are far
too difficult for us to copy or I expect we should do
so. For example, watch a goldfish and see how
cleverly it uses its tail. Man could never hope to
make anything so perfect as that tail. Absolutely
under its owner's control, it serves a double purpose of
propelling and steering in a manner which is equally
beautiful and impossible to imitate.
For certain definite purposes, however, a rotary
propeller is quite as good as anything which the
fishes can show us. As a straightforward, simple,
forward-pushing device it is equal to anything that
a fish possesses. It has to be given that one duty,
however, and no other, the steering being the task of
a separate device, the rudder. There again, too, we
see how nature does two things with one kind of
mechanism while we have to use two, for the fish
steers itself to right and to left with its tail in a
vertical plane, but if it wants to steer upwards or
downwards it twists its tail over somewhat towards a
horizontal plane. The submarine, however, needs
two distinct and separate rudders, one for right and
left steering and one for up and down, the latter
being generally a pair, one each side the vertical
rudder for the sake of symmetry and balance.
So we find that a submarine has a body like that
of a fish except that it is rather more rotund, perhaps,
than the most portly fish usually seen. It has
certain fixed fins projecting from its sides, which
together with the rudders enable it to be guided. It
224
WHAT A SUBMARINE IS LIKE
has also certain long fins called bilge keels for the
purpose of keeping it from rolling too much. Also, it
has one or more propellers and the two kinds of
rudder already referred to.
A fish, never wishing to get outside itself and walk
about upon its own upper surface, needs no deck, in
which the submarine differs from it, for the crew
require somewhere where they can enjoy a breath of
fresh air when opportunity offers. It is not a very
commodious place, one could not exactly take a long
walk upon it, nor even play deck-quoits, but on the
back of the submarine there is an undoubted deck
where the men can get out and upon which they can
stand when she is on the surface.
A fish, moreover, takes little heed of things upon
the surface : its interests lie almost entirely below.
Hence it has no conning-tower or periscope, but with-
out these the submarine would be useless. The
former is a little oblong tower something like a
chimney, which projects upward from the deck, while
projecting to a higher level still is the tall hollow
mast with prism and lenses at the top called the
Periscope, through which the commander of the
submarine, himself comparatively inconspicuous, can
sweep the horizon for enemies or victims.
The problem of constructing a ship to travel under
water is quite different from making one to travel on
the surface in the ordinary way. When deep down
the pressure of the water tending to crush the vessel
is something enormous. Roughly speaking, it is a
pound per square inch for every two feet in depth,
so that if a submarine dives to a depth of fifty feet
p 225
WHAT A SUBMARINE IS LIKE
the water presses upon it with a force of about
twenty-five pounds upon every square inch of its
surface. On a square foot, that means over a ton.
And there are many square feet of the surface in even
a small submarine. Consequently, the whole shell of
the ship has to be of very substantial construction.
Moreover, there are curious strains which come upon
the vessel when it dives to which surface ships are
not subject. All these have to be reckoned as far as
possible and allowed for.
The size of the modern submarine is not known
with any certainty, but we may put it down roughly
as two hundred feet long and at least a thousand tons
displacement, which means that that is its actual
weight, including everything and everybody on
board, when it is just about to submerge.
Of course, a submarine, alone among boats, has
two " tonnages." When it is on the surface it is
comparatively light. Indeed, " running light " is
the technical term describing it when it is riding upon
the surface of the water like an ordinary ship. Then,
by increasing its weight, it can cause itself to sink
until the little promenade or deck called the super-
structure is just submerged and little can be seen
above water except the conning-tower. That is
termed the " awash " position, and it is clear that
it is then displacing more water than when running
light, and hence its displacement tonnage must
be more.
When it is desired to sink, the vessel is set in
motion in the awash position, from which it is gradu-
ally steered downwards by the diving rudders, until
226
WHAT A SUBMARINE IS LIKE
only the periscope, or it may be not even that, is left
showing above. Then the maximum of water is being
displaced. It is then actually displacing more than
its own weight of water, for if left to itself it will
rise rapidly and it is only the speed and the action of
the rudders which keep it under. We see, then, that
the action of a submarine in submerging itself is a
real genuine dive. It sinks upon an even keel until
it is awash, after which it goes under " head-first,"
just as a swimmer does. It also rises bow first.
This tendency to rise when the combined action of
movement and rudder ceases constitutes a very con-
siderable safeguard, for should anything happen to
the propelling machinery the vessel simply rises.
At one time weights were attached to the under side
of the hull which could be detached from the inside so
that in the event of the vessel descending against the
wish of her commander, she could be simply forced
to the surface by the great excess of buoyancy result-
ing from shedding these " safety weights." Of
course, in the event of a serious perforation of the
hull neither of these forms of surplus buoyancy would
bring the boat up.
Let us now trace the operations of diving right
through, supposing that our submarine is first
running light. In that condition she is being driven
by the oil engines which constitute her primary
propelling power. The hatch or door at the top of
the conning-tower is open, as also, it may be, is the
one lower down, just at the foot of the tower. Men
are standing upon the little platform formed by the
tower, and one of them is steering by means of a wheel
237
WHAT A SUBMARINE IS LIKE
keeping his eye, moreover, upon a compass also
provided there, that being in fact, to the submarine
when light, what the bridge is to the ordinary
steamer. Other members of the crew may be upon
the superstructure or deck just below, while others
again are down inside, attending to their duties there.
Under these conditions the inside is by no means
an unpleasant place. Plenty of fresh air comes down
through the open hatches and through the ventilators,
it being drawn down through the latter by means
of a fan.
Preparations are then made for submerging. The
hand-rail along the little deck is removed. The upper
steering wheel and compass are covered up or shut
away into the coverings provided for them, the
wireless apparatus, if provided, is removed and the
mast shut down. Hatches are securely closed and
valves in the ventilating pipes are closed. In fact
every opening is shut and made water-tight so that
no risk shall be run of diving prematurely and taking
in water accidentally.
The quarter-master transfers himself to the
steering wheel inside, where he has another compass
to guide him, not of the magnetic variety this time
but a cunning application of the gyroscope. The
commander, too, having descended before the last
hatch was closed down, takes his stand at the eye-
piece of the periscope, since that is now his only means
of seeing what is going on above.
Another man takes his place at the wheel which
controls the diving rudder, conveniently near to
which* is a pressure gauge so connected to the outer
228
WHAT A SUBMARINE IS LIKE
water that as the ship dives its depth is recorded upon
its dial : that in effect is to him what the compass is to
his comrade at the other wheel.
With every movement of men there needs to be
adjustment made to keep the ship on an even keel.
Otherwise she would go down by the bow or down by
the stern according as the men's weight shifted
towards either end. This is arranged for by two small
tanks formed in the structure of the vessel, one at
either end. Connected together by pipes and con-
trolled by compressed air, water can be transferred
from one to the other at will and so the balance be
always kept. Quite simple manipulations of a valve
serve to accomplish this delicate balancing perform-
ance. It is perhaps not of such importance at this
stage, but in a moment, when the whole vessel will be
under water, a very little movement indeed will
suffice to upset the equilibrium.
Next water ballast is admitted into certain other
spaces in the ship's structure, these spaces being
called, because of the use to which they are put,
ballast tanks. Gradually, as the incoming water
increases the weight of the vessel, she sinks until she
is awash. Then the diving rudders are set at the
right angle (a pendulum serves to show the angle
at which the boat points) and down she goes. As
the pressure-gauge indicates the approach to the
required depth the rudder is flattened out a little
until just that position is found which keeps the boat
under at the desired depth.
Of course, when all hatches and openings were
closed the supply of fresh air was cut off and after
229
WHAT A SUBMARINE IS LIKE
that the crew had to depend upon the air contained in
the submarine. Also, they had to stop the engine,
for without air it cannot work : nor can it work
without giving off fumes, which, if admitted to the
ship, would soon suffocate the crew. Just before
closing up, therefore, the engine is stopped and
electric motors take up the task of driving the ship.
Now suppose that, while running submerged, the
commander espies, through his periscope, an un-
suspecting enemy. He tries forthwith to get as
close as he can. Having noted the direction of the
vessel and which way she is going and as far as
possible her speed, he submerges more deeply, in all
probability, lest the white streak which represents
the wake caused by his periscope should reveal his
presence. For possibly she is one of those terrible
destroyers in fair fight with which he has but a poor
chance. His only safety lying in complete invisi-
bility, he therefore submerges entirely, trusting to his
calculations to lead him in the desired direction. Thus
he attempts and, if he have good luck, he succeeds in
getting reasonably near to his foe.
Then he must try so to manoeuvre that his bow
shall at the right moment be pointing towards the
quarry, for his torpedo tubes are in the bow and
they are fixed, or nearly so at all events, so that he
can only fire them in a direction nearly, if not
precisely, in the direction of the centre line of his
ship.
Nay, he must do even more than that. It will not
do to fire the torpedo directly at the ship, for a torpedo
is comparatively slow. Suppose it is capable of
230
WHAT A SUBMARINE IS LIKE
forty miles an hour, and the other ship is a mile away :
the torpedo will take ninety seconds to reach it. And
in that time it may have travelled a mile or so itself.
So the submarine man has to allow for that.
Occasionally, therefore, he comes up a little for a
moment in the hope of getting a sight of the enemy
while not revealing his own presence. Or perhaps he
may decide to risk being seen and caught, trusting to
the chance of getting his own blow in first. He needs
to be a most resourceful man, with clear and keen
judgment and supreme self-confidence, or he can
never grapple with such a task.
Supposing, then, that he succeeds in getting
undetected into a favourable position, as he thinks ;
at the critical moment the other ship may change its
course, and the whole scheme goes awry. Perhaps he
then tries to follow, but that is bad, for the end of
a ship is not nearly so good a target as the side and
the part hit is not so vulnerable. The first torpedo
may, however, so disable the vessel as to give him
chance to get into position for a second and better
shot.
Anyway, when he thinks he has got his best chance
he lets off a torpedo, immediately diving to be safe
out of harm's way for a while. Then he rises to see
the result of his work. If successful he would be sure
to hear the sound, for water is an excellent sound-
conductor and a submarine is like a gigantic tele-
phone ear-piece.
It must be a nerve-racking job at the best of times,
for the submarine is a very vulnerable craft. A
member of the crew of a German submarine captured
231
WHAT A SUBMARINE IS LIKE
during the war is reported to have said that out of
ten submarines attacked, nine were sunk. That may
or may not be true, but it is certain that a very little
damage, which would hardly affect an ordinary craft,
is enough to sink a submarine. That is because, in
order to be able to sink at will, the reserve of buoyancy
has to be very low. An ordinary surface ship has at
least as much of its bulk above water as below : hence
it can take on board a weight of water almost equal
to, if not exceeding its own weight before it sinks.
At the best a submarine has not more than 30 per
cent of excess and so it sinks if water amounting to
only 30 per cent of its weight gets into it. In other
words, the reserve in one case is at least 100 per cent :
in the other at most 30 per cent.
During the war a submarine saw and tried to track
down, somewhat after the manner described, a slow,
steady-going collier which plies between London and
the north carrying coal for a London gas-works.
Having, as it thought, got into position for dis-
charging its torpedo it rose for a final look when (it
must have been to the amazement of the crew) the
collier was seen making straight for them. What
they really thought no one will ever know, for the
collier had the best of the encounter, the submarine
was crushed beneath her blunt bows and sank, no
doubt, for ever. The mere fact that a slow, clumsy,
heavily-laden collier could ever thus vanquish an up-
to-date submarine is eloquent testimony to their
vulnerability.
Many a submarine, too, has fallen to the shells of
an armed fishing trawler simply because the shells of
232
WHAT A SUBMARINE IS LIKE
the latter were so much quicker in action than a
torpedo, coupled with the fact that one well-placed
shot, by preventing a submarine from diving, renders
it almost helpless.
Some submarines, however, have a gun on the
deck, so that when light they can fight like a destroyer
or other lightly-armed vessel. The gun shuts down
into a cavity when the vessel goes below.
The periscope, which forms such an important part
of the submarine's equipment, is really very little
more than a telescope. On the top there is a little
mirror, or more probably a prism or three-cornered
piece of glass which serves precisely the same purpose
in that it reflects exactly as a mirror does. This is
so placed that it throws the light from distant
objects down the tube into the interior of the ship.
In the tube are lenses very like those of an ordinary
telescope and the light may be made to throw a
picture upon a little table or screen or else can be
viewed through another prism directly by the eye.
In either case the periscope is just like an ordinary
telescope set up vertically with a prism at the top
so that it can " see " at right angles, and possibly
another at the bottom so that the picture can
be viewed at right angles to the direction of the
tube. The latter is necessary only for the con-
venience of the observer, since otherwise he would
have to lie upon his back to look up the tube.
The whole apparatus can be rotated mechanically
and a scale forms a means of measuring the
precise direction in which the prism or mirror
is at any moment pointed. This is useful for
233
WHAT A SUBMARINE IS LIKE
measuring roughly the position of the " prey," and
it may even be used as a rough means of getting the
range.
Another feature is the gyroscope compass, to which
a passing reference has already been made. It is
fairly well known that an object when spinning
exhibits properties quite different from those which
it possesses when still. A boy's top is a familiar
illustration, for while spinning it will stand perfectly
steady, supported only upon a tall peg with a sharp
point, a pose which it will absolutely refuse to main-
tain when not spinning. Now fortunately for the
present purpose it so happens that one of the pecu-
liarities of the gyroscope or spinning-wheel is this :
that if mounted in a certain way it persists in placing
its axis in the same plane as that in which the axis
of the earth lies. If you imagine for a moment a
plane or flat surface of which the earth's axis forms
a part you will see that wherever that plane cuts the
surface of the earth will be a line in a north and
south direction. Consequently, if any horizontal
object has its axis in that same plane it, too, will
always point north and south. A wheel, small but
heavy, is therefore mounted with its axis supported
horizontally upon a little metal raft floating in a
trough of mercury and driven round at a very fast
speed by a small electric motor fixed in it.
Whatever its position may be to start with, this
revolving wheel will in a short time slew itself round
upon the supporting mercury until its own axis is in the
same plane as the axis of the earth : until, in fact, its
axis points due north and south. Arrived in that
234
WHAT A SUBMARINE IS LIKE
position, it will remain there no matter how the ship
upon which it stands may turn. Since it floats freely
upon mercury the motion of the ship has little effect
upon it, so little indeed, that it has no difficulty in
following its own peculiar bent, even if the ship be
describing circles.
The advantages of this are various : two of them
may be stated. First, the apparatus points to the
actual geographical north and not to the magnetic
north, which is a slightly different direction and one,
moreover, subject to frequent variation. Second, it is
absolutely unaffected by the presence of iron or other
magnets, a very fruitful source of error in the
magnetic compass when used upon an iron ship
close to steel guns and electrical machinery. Sur-
rounded with iron as is the compass in the interior of
a submarine, the magnetic needle practically refuses
to work at all, so that, although employed on other
ships, it is on the submarine that the gyro-compass
finds its most important field of usefulness.
The pressure-gauge or manometer, which indicates
the depth, is probably not different in any respect,
except in its dial, which is marked in feet-depth
instead of in pounds-pressure, from the pressure-
gauge used on steam boilers. It has either a little
cylinder with a piston in it which the water presses
upwards more or less against the force of a spring, a
diaphragm which is bent more or less, or a bent tube
which tries to straighten itself out as the pressure
inside it increases.
The older submarines derived their power from
petrol engines similar to those which drive high-
235
WHAT A SUBMARINE IS LIKE
power motor-cars, but nowadays these have given
place to engines of the type invented by the unfortu-
nate Diesel who, after making one of the most
brilliant and successful inventions of modern times,
committed suicide, apparently in the height of his
success.
These engines burn cheap heavy oil in place of the
costly refined petrol : they are exceedingly reliable
and well-behaved, and are free from many of the
troubles which affect the petrol motor. They are
referred to in more detail in another chapter.
In twin-screw boats there are two distinct engines,
one for each propeller. Each engine, too, is coupled
to a dynamo by which it can generate electric
current, which is stored in large accumulator batteries
nutil required and then withdrawn to drive the
dynamos as motors while the boat is submerged,
for if you feed a dynamo with current it becomes a
motor.
A great deal of work is done, on the submarine, by
compressed air, of which large stores are carried in
strong steel cylinders. For example, the ballast is
ejected from the ballast tanks, when the boat is
required to rise, not by pumps but by the action of
compressed ah* from a cylinder. The simple move-
ment of a tap thus suffices to blow out the water in a
very short time. The torpedoes, too, are given their
initial push which sends them out of their tube into
the water by compressed air. In other ways, too,
compressed air is employed and to facilitate its use
there are many tubes and valves whereby the
cylinders and other apparatus are connected. Like
236
WHAT A SUBMARINE IS LIKE
all things human, these tubes and valves have their
defects, which in this case means that they leak
somewhat, but this defect is of value since the
leaking air helps to keep pure and sweet the air
inside the boat which, when submerged, the men
have to breathe.
To what extent it is used I do not know, but it
is a fact that certain chemicals, caustic soda for
instance, have the power to absorb the objectionable
carbonic acid which makes tightly-shut rooms seem
" close " and uncomfortable, and if something of
that sort be employed, it, together with the fresh air
which thus leaks in by accident, is undoubtedly
enough to enable men to live under water for many
hours at a stretch.
On the other hand, several instances are on record
in which strong healthy young officers have, after a
course of service on a submarine, been found to be
suffering seriously from chest and lung trouble,
brought on, no doubt, by long spells of duty in this
unhealthy atmosphere
It used to be the custom to keep some white mice
on board a submarine to give warning of the im-
purities in the air. Being very susceptible to the
smell of petrol vapour, which used to be a source of
considerable danger, and also to carbonic acid, these
little creatures squeaked with anxiety some time
before the conditions became really dangerous, thus
giving timely warning. There is an instrument,
however, which will give an indication of this sort
and probably it has been brought in to reinforce the
mice if not actually to supplant them. This interest -
23?
WHAT A SUBMARINE IS LIKE
ing little instrument, which the gasworks people use
for detecting leakage, consists of a metal drum with a
porous diaphragm. Normally the pressure of the
atmosphere upon the diaphragm is equalled and
balanced by the pressure of the air inside the drum,
but if there be gas in the air this balance is upset, the
diaphragm is bulged in or out and a finger is thereby
moved, which movement forms a measure of the
amount of gas present.
In conclusion, we may fittingly take a glance at
what happens when a submarine founders. Only a
few years ago this occurred with lamentable frequency,
though now it is quite rare except under the actual
stress of warfare. Several interesting schemes were
therefore invented to give the men at least a sporting
chance of getting to safety. One was to make the
conning-tower detachable and water-tight, so that
the men could get into it, fasten themselves in and
float up to the surface. The practical difficulties in
the way prevented this being a success. For example,
if sufficiently detachable in an emergency it was
difficult to make it sufficiently water-tight in ordinary
use.
Another and better device provided the men with
small helmets and jackets, like the dress of a diver
very much simplified. One of these for each man was
stored in an accessible place in the boat and partitions
were devised inside the hull itself in order that what-
ever happened there should be air entrapped some-
where wherein the men could live for a time and put
on their helmets in safety. Then, thus provided,
they could crawl out through the hatchway and
238
WHAT A SUBMARINE IS LIKE
float up to the surface. Arrived there they could
inflate their jackets by blowing into them, open the
window of the helmet and float upon the surface in
comparative safety until rescued.
This apparatus was largely installed in British
submarines and a tank was built at Portsmouth
where the men could actually practise with it under
water.
A third device may also be mentioned. This takes
the form of a buoy fitted into a recess in the boat's
upper surface. Sufficient line is coiled up inside it
and when the occasion arises it can be released from
inside. This does not in itself save the crew but it
may go a long way towards ensuring their safety by
letting those above know just where the sunken craft
is and guiding them in their efforts to raise it.
The torpedo, the weapon without which the
submarine would be practically useless, is dealt with
in another chapter. Enough has been said here to
give a good general idea of these interesting craft,
their fittings, their uses and the sort of life which
befalls those who man them.
239
CHAPTER XX
THE STORY OF WIRELESS
TELEGRAPHY
FOR ages people were puzzled as to the nature
of light. Pythagoras, that old Greek who
invented what we now call the forty-seventh
proposition of Euclid, thought that the bright body
shot off streams of tiny particles which literally hit
the observer in the eye. Sir Isaac Newton thought
the same, but for once " the greatest scientist of all
time " was wrong.
For when the Danish astronomer, Romer, dis-
covered that light travelled at the rate of somewhere
about 186,000 miles per second it dawned upon
people that it was scarcely believable that particles
of any kind could by any means be made to move so
fast. So they set about searching for a new explana-
tion, and they found it in the idea that light was
conveyed from the bright body to the observer's eye
by means of waves, and as there cannot be waves of
nothing they had to imagine a something to exist in
all the vacant spaces of the universe capable of form-
ing the waves of light. This something was called
the luminiferous ether or light-bearing ether. We
can neither see, feel, taste nor hear it. Our senses
240
STORY OF WIRELESS TELEGRAPHY
tell us nothing about it. Indeed, if it does really exist
it must be so very different from anything that we
do know by our senses that one is often tempted to
doubt its existence. Still, it explains so many things
which are otherwise unexplainable and enables us so
correctly to reason from one phenomenon to another
that our reason forces us to accept it as a fact, at all
events until something better comes along.
This wave theory in regard to light was finally set
at rest by the curious discovery about a century ago
by Dr. Thomas Young of London that if two lots of
light were brought together in a certain way they
produced darkness.
Now if a ray of light were a stream of particles,
two such rays would inevitably and always, if added
together, produce a doubly brilliant light, and under
no conceivable circumstances could they do anything
else. But two lots of waves can, and do, under the
proper conditions, neutralize each other so as to
produce rest.
This mutual action upon each other of two sets of
waves can be very simply exhibited by two violin
strings tuned to nearly but not quite the same note.
If you have a violin handy, try it and you will find
that when either string is plucked separately it gives
a steady continuous sound, but if both be plucked at
the same time they give a throbbing sound. That is
because, periodically, as one string is coming up the
other is going down, so that they neutralize each
other, while at other times, owing to the fact that one
is vibrating faster than its fellow, both are rising and
falling together. When neutralizing each other there
Q 241
STORY OF WIRELESS TELEGRAPHY
is a momentary silence, while in between the silences
come the times when both are acting together and
therefore producing a specially loud sound. And so
as the vibrations of the faster keep gaining upon those
of the slower string one hears a continual crescendo
and then diminuendo repeated over and over again.
So two sets of sound waves sometimes produce silence.
And hi like manner two sets of light waves can be
made so to " interfere " (that is the technical term)
that together they produce darkness.
So for a hundred years or more people have, gener-
ally speaking, accepted the idea that light consists
of waves in a medium called The Ether. Heat also is
brought to us from the sun and from any distant hot
body by similar means, the difference between light
waves and heat waves being simply in their wave
length or the distance apart. The different colours
of light, too, are to be accounted for by different wave
lengths.
You have of course seen how a magnet can act
upon a piece of iron at a distance. You may, too,
have tried the experiment of jerking a magnet past
a piece of wire, thereby generating an electric current
in the wire. Both those things need, for explanation,
that we assume the existence of a something invisible
and undetectable by our senses between the magnet
and the iron and between the magnet and the wire,
by which the action of one is conveyed to the other.
So people imagined another Ether capable of acting
like a link between the magnet and the iron and
between the magnet and the wire.
Now just about half a century ago a celebrated
242
STORY OF WIRELESS TELEGRAPHY
professor of Cambridge University brought all these
facts about light, heat, magnetism and electricity
together and by skilful reasoning showed that but
one Ether sufficed to explain all these things. He
showed how magnetic and electric forces acting to-
gether could produce waves like those of light and
heat. And finally he demonstrated by figures that
waves so formed would necessarily travel at the very
speed at which light and heat are known to move.
This is known as the electro-magnetic theory of
light. And not content with showing the nature of
things already known, Professor Clerk-Maxwell added
a prophecy that there were other waves in existence
of longer wave length, which no one then knew how
to make or to detect if made.
Following up this prophecy many investigators
sought these waves, and the first to find them was
Professor Hertz of Carlsruhe in Germany. For-
tunately for his position in the minds of English
people he died before the War, so that his name is
not sullied by the stupidities of which German pro-
fessors in more recent days have been guilty. On the
contrary, his writings show him to have been a
kindly, modest, genial soul, and particularly gratify-
ing is his generous assertion in one of his books that
had he not himself discovered these waves he is certain
Sir Oliver Lodge would have done so. He seemed quite
anxious to share the credit of his discovery with his
" English colleague " as he called him.
Let us see then how these " Hertzian waves " are
produced. In the year 1748 a Dutch experimenter
named Cuneus thought he would try to electrify
243
STORY OF WIRELESS TELEGRAPHY
water. He got a glass flask and filled it with water
into which he let drop one end of a chain connected
to an old-fashioned frictional electrical machine. Thus
he stood with the flask in his hand while a friend
worked the machine. After a short time the friend
stopped and Cuneus took hold of the chain to lift it
out, when to his astonishment he received a shock
which knocked him over, broke his flask and sent
him to bed to recover.
Unwittingly Cuneus had invented what became
known thereafter as a Leyden jar, Leyden being the
town in which he lived. It consisted, you will notice,
of two conductors, the water and his hand, with an
insulator, the glass, in between.
To understand or rather to give ourselves a useful
working explanation of how such an apparatus comes
to be charged we must first imagine that everything
contains a certain normal amount of electricity
which we can by certain means add to or take away
from at will. When we add some to anything we say
we have given it a positive charge : when we sub-
tract some we say that we have imparted a negative
charge. Clearly, if we add some to one thing we
must first obtain it from something else, and if we
take some away from one thing we must do something
with what we have taken, and so we add it to some-
thing else. Therefore whenever we charge anything
positively we must charge something else negatively
and vice versa.
Now the ease with which we can thus charge two
bodies seems to depend upon their nearness to each
other, so that the easiest things to charge are two
244
STORY OF WIRELESS TELEGRAPHY
plates of metal separated by the thinnest possible
insulator. Modern Leyden jars are usually formed
of a thin glass jar with a lining inside and out of tin-
foil.
The Leyden jar is, however, only one form of the
piece of electrical apparatus known as an electrical
condenser, and many other forms exist. For example,
a flat sheet of glass with foil above and below, or
several such piled one on top of another. An eminent
electrician whom I know has recently made some of
two tin patty pans put bottom to bottom, nearly but
not quite touching, the whole being enclosed in a
solid block of paraffin wax. And I might describe
many other forms, but whatever they may be every
one is essentially two conductors with an insulator
between.
Now when a condenser has been charged its charges
remain for a considerable time unless they be given a
chance to escape. Suppose you have a charged con-
denser and that you take a wire and with it touch
simultaneously both the conductors, the surplus on
one " plate " will rush through the wire and make
good the deficiency upon the other ; it will thus in
an instant become discharged .
Now several scientific men had suggested, before
Hertz's time, that when that occurred something else
happened too. They thought that the charge did
not simply rush from one plate to the other instantly,
but that it oscillated to and fro for a period ; that the
surplus rushing round overshot the mark, so to speak,
and not only made up the deficiency but caused a
surplus on the opposite plate, after which this new
2 45
STORY OF WIRELESS TELEGRAPHY
surplus rushed back again through the wire, doing
the same thing, though to a less and less degree,
several times over before a condition of perfect rest
was reached. To use a simple analogy, it was thought
that the surplus swung to and fro like the swinging
of a pendulum. We know that a pendulum swings
because of its inertia, and electricity possesses a
property very like inertia which, it was thought,
would cause it to behave in the same way.
The Ether waves travel at the rate of 186,000 miles
per second, so that if, as was thought, a sudden
current of electricity gives rise to a wave, currents
which succeed each other at the rate of one per
second would produce waves 186,000 miles apart. A
hundred currents per second would give a wave
length of 1860 miles. A thousand per second would
give 186 miles. But a thousand succeeding currents
per second are difficult to produce, and 186 miles is
so very much greater than the tiny fraction of an
inch, which is the length of the light and heat waves,
that Hertz had to find some way of making currents
succeed each other faster even than a thousand times
per second.
So he thought of these oscillating currents which
were supposed to occur when a condenser was dis-
charged, and he rigged up a condenser with an induc-
tion coil and a spark gap in a way which he thought
would do what he wanted.
There is not room here to explain the Induction
Coil, indeed it is so well known that it will be quite
sufficient to state that it is an apparatus which takes
steady current from a battery and gives back instead
346
STORY OF WIRELESS TELEGRAPHY
a lot of little spurts or splashes of current at a rate of,
say, fifty or one hundred splashes per second, accord-
ing as we adjust the little vibrating spring which
forms a part of the coil. We can so connect this to
a condenser that each splash will charge it up ; and
we can combine with it a spark-gap, that is to say, a
gap between two knobs, so that every time it is
charged it immediately discharges again through
this gap. Thus we may have, say, one hundred
splashes per second, and each splash is followed by
several oscillations across the air-gap, the oscillations
taking place at the rate of perhaps a million per
second. Each series of oscillations is called a
" train."
Now a million per second gives a wave-length some-
where about what Hertz wanted, so he arranged his
apparatus as just described.
For a condenser he used two metal plates a little
distance apart, the air between forming the insulating
material. He set up his apparatus in a large room,
and having started the coil he moved about with a
nearly complete hoop of wire, the ends of which
nearly touched. Working in darkness he found after
a while that sometimes he could see little sparks, very
small but just visible across the gap between the ends
of the bent wire. Those sparks only occurred when
the coil was in action, and so he knew that the one
was the result of the other's work. By careful pains-
taking experiment he found that the sparks were un-
questionably caused by waves, and that the waves
moved with the same speed as light, also that they
could be reflected and refracted just on precisely the
247
STORY OF WIRELESS TELEGRAPHY
same principles as those which control light. More-
over, he measured the wave-length.
At first sight it seems incredible that anyone could
measure the distance apart of waves which travel
at such a speed as 186,000 miles per second, but for-
tunately, by a special application of " interference,"
it is possible to make the waves stand still and tamely
submit to measurement. An example of this can be
seen by simply tapping a glass of water, when the
ripples being reflected off the sides interfere with each
other and become stationary. Stationary waves are
half the wave-length of the original waves, and by
using this method Hertz was able to make a measure-
ment which at first sight seems beyond the bounds
of possibility.
Thus Hertz discovered how to make the waves
which Clerk-Maxwell had predicted and also how to
detect them when made.
It was not long before the idea arose of using these
waves for signalling to a distance. Many experiments
were made but with no very striking success until
1896 when Marconi first came to England.
Hertz had noticed that the farther apart he placed
the plates of his condenser the farther could he get
his tell-tale spark, so Marconi saw that the plates of
his condenser, too, must be far apart. He also found
that the earth could be used as one of the plates, that
in fact there was a great advantage in so using it.
So, one plate having to be the earth itself and the
other removed as far as possible from it, the tall
masts of the wireless antenna came into being.
When Marconi came to England he was taken under
248
LISTENING FOR THE ENEMY.
Special sensitive cylinders are sunk into the ground to which the usual telephonic
apparatus is fixed. This enables the sappers to detect any underground operations by
the enemy.
STORY OF WIRELESS TELEGRAPHY
the kindly wing of Sir William Preece, the veteran
engineer of the Post Office, and the facilities which
Sir William was able to give no doubt helped largely
in his subsequent rapid progress. After a few experi-
ments in London he got to work across the Channel,
sending messages from the North Foreland Light-
house to Wimereux on the coast of France, in-
cluding congratulatory messages between the French
authorities and good Queen Victoria.
A little later he was signalling from Niton in the
Isle of Wight to the mainland and to the far west at
the Lizard. The first wireless telegram which was
actually paid for was sent by Lord Kelvin, the father
of cable telegraphy, from Niton to the mainland,
whence it was transmitted by land wires to Sir George
Stokes. This incident, so interesting because of its
marking a stage in the history of this great invention,
also because of the persons concerned, occurred in 1898.
But Marconi was quickly increasing the range of
his apparatus far beyond anything already men-
tioned. He journeyed in the Italian warship Carlo
Alberto as far north as Cronstadt and as far east as
Italy, keeping in communication with England all
the time. Then he crossed the Atlantic, again keeping
up communication with England the greater part of
the journey.
Raising his wires to a great height by means of
kites he was soon able to signal from Nova Scotia to
the great station just previously built at Poldhu in
Cornwall, and then wireless telegraphy from land to
land across the great ocean became an accomplished
fact.
249
STORY OF WIRELESS TELEGRAPHY
We all know how things have progressed since
then. A telegram by Marconi is as commonplace
to-day as a telegram by cable. The British Govern-
ment is now engaged upon a series of stations dotted
about the globe in such a way that every part of the
widely separated British Empire shall be in constant
touch with every other part by wireless telegraphy.
In other words, the range of the system has now
become such that nothing further is needed.
The British Admiralty has a few wires slung to
posts on the top of the offices in London, and those
few wires enable touch to be maintained with ships.
As almost every intelligent newspaper reader in Great
Britain knows, the Germans were in the habit, during
the war, of sending news to the United States by
wireless telegraphy, which news was always picked
up by the Admiralty installation and circulated to
the British newspapers, often to the amusement of
their British readers.
The famous Emden, too, which had such a run of
success until it encountered the Australian cruiser
Sydney, met its end entirely through the intervention
of wireless telegraphy.
These incidents give us a good idea of the useful-
ness of wireless in naval warfare. In military work
it is used chiefly in connection with air-craft, but of
that more will be said in another chapter.
250
ss *
g i
w 8
CHAPTER XXI
WIRELESS TELEGRAPHY IN WAR
THE history of this wonderful invention has
been described in the preceding chapter. Now
we will see how it is applied in warfare.
Let us take first its uses in connection with the
Navy. The aerial wires or antenna are stretched to
the top of the highest mast of the vessel. Where there
are two masts they often span between the two.
Ships which have masts for no other reason are sup-
plied with them for this special purpose. In the case
of submarines, the whole thing, mast and wires in-
cluded, is temporary and can be taken down or put
up quickly and easily at will.
The stations ashore are equipped much after the
same manner as are the ships, except that sometimes
they are a little more elaborate, as they may well be
since they do not suffer from the same limitations.
For example, the well-known antenna over the
Admiralty buildings in London consists of three masts
placed at the three corners of a triangle with wires
stretched between all three.
However these wires may be arranged and sup-
ported they are very carefully insulated from their
supports, for when sending they have to be charged
with current at a high voltage and need good insula-
252
WIRELESS TELEGRAPHY IN WAR
tion to prevent its escape, while, in receiving, the
currents induced in them are so very faint that good
insulation is required in order that there may not be
the slightest avoidable loss.
The function of these wires, it will be understood,
is to form one plate of a condenser, the earth being
the other plate and the air in between the " dielec-
tric " or insulator.
In the case of ships " the earth " is represented by
the hull of the vessel. It makes a particularly good
" earth " since it is in perfect contact with a vast
mass of salt water, and that again is in contact with
a vast area of the earth's surface. Salt water is a
surprisingly good conductor of electricity.
In land stations " earth " consists of a metal plate
well buried in damp ground. The whole question of
conduction of electricity through the earth is very
perplexing. There seems to be resistance offered to
the current at the point where it enters the ground,
but after that none at all. Consequently the resist-
ance between two earth plates a few yards apart and
between similar ones a thousand miles apart is about
the same. Though the earth is made up mainly of
what, in small quantities, are very bad conductors
indeed, taking the earth as a whole it is an exceed-
ingly good conductor. That makes it all the more
important that where the current enters should be
made as good a conductor as possible, and the con-
struction and location of the earth plates is therefore
very carefully considered so as to get the best results.
Wires, of course, connect the antenna to the earth,
thereby forming what is called an " oscillatory cir-
253
WIRELESS TELEGRAPHY IN WAR
cult." The ordinary electric circuit is a complete
path of wire or other good conductor around which
the current can flow in a continuous stream. An
oscillatory circuit is one which is incomplete, but the
ends of which are so formed that they constitute the
two " plates " of a condenser. In that way, according
to theory, the circuit is completed between the two
ends by a strain or distortion in the " Ether " between
them. A continuous current will not flow in such a
circuit, but an alternating, intermittent or oscillating
current will flow in it in many respects as if there
were no gap at all but a complete ring of wire.
At some convenient point in this oscillatory circuit
are inserted the wireless instruments, one set for
sending and the other set for receiving, either being
brought into circuit at will by the simple movement
of a switch.
In small installations the central feature of the
sending apparatus is an Induction Coil operated by
a suitable battery or by current from a dynamo. Con-
nected with it is a suitable spark gap consisting of
two or three metal balls well insulated and so arranged
that the distance between them can be delicately
adjusted. This is generally done by a screw arrange-
ment with insulating handles, so that the operator can
safely adjust them while the current is on.
The current from the battery or dynamo to the
coil is controlled by a key similar to those used in
ordinary telegraphy, the action being such that on
depressing the key the current flows and the coil
pours forth a torrent of sparks between the knobs of
the spark-gap, but on letting the key up again the
254
WIRELESS TELEGRAPHY IN WAR
sparks cease. Since the sparks send out etherial
waves which in turn affect the distant receiving
apparatus it follows that a signal is sent whenever
the key is depressed. Moreover, if the key be held
down a short time a short signal is sent, but if it be
kept depressed for a little longer a long signal is sent,
by which means intelligible messages can be trans-
mitted over vast distances.
Certain specified wave lengths are always used in
wireless telegraphy. That is to say, the waves are
sent out at a certain rate so that they follow each
other at a certain distance apart. In other words, it
is necessary to be able to adjust the rate at which the
currents will oscillate between the antenna and earth.
Every oscillatory circuit possesses two properties
which are characteristic of it. These two properties
are known as Capacity and Inductance. It is not
necessary to explain here what these terms mean
precisely. It is quite sufficient just to name them
and to state that the rate at which oscillations take
place in such a circuit depends upon the combined
effect of these two properties. Consequently, if we
can arrange things so that capacity or inductance or
both can be added to a circuit at will and in any
quantity within limits, we can within those limits
obtain any rate of oscillation which we desire and
consequently send out the message-bearing waves at
any interval we like ; in other words, we can adjust
the wave-length at will.
Fortunately, it is very easy to add these properties
to an oscillatory circuit in a very simple manner. A
certain little instrument called a " tuner " is con-
255
WIRELESS TELEGRAPHY IN WAR
nected up in the circuit and by the simple movement
of a few handles the desired result can be obtained
quickly even by an operator with but a moderate
experience. He has certain graduated scales to guide
him, and he is only called upon to work according to
a prearranged rule in order to obtain any of the
regulation wave-lengths.
As a matter of fact, the instruments are not directly
inserted in the antenna circuit, the circuit that is
which is formed by the aerial wires, the earth and
the inter-connecting wires. Instead, the two sides
of the spark-gap are connected together so as to form
a separate circuit of their own, the local circuit as we
might call it, and then the two circuits, the antenna
circuit and the local circuit, are connected together
by " induction."
A coil of wire is formed in each, and these two coils
are wound together so that currents in one winding
induce similar currents in the other winding, and by
that means the oscillations set up by the coil in the
local circuit are transformed into similar oscillations
in the antenna circuit. This transformation involves
certain losses, but it is found in practice to be by far
the most effective arrangement. Both the circuits
have to be tuned to the desired wave length, but that
is done quite easily by the operation of the handles
in the tuner already referred to.
It is to this coupling together of tuned circuits that
Marconi's most famous patent relates. It is registered
in the British Patent Office under the number 7777,
and hence is known as the " four sevens " patent.
It has been the subject of much litigation, which
256
WIRELESS TELEGRAPHY IN WAR
proves its exceptional importance, and it is to the
fact that the Marconi Company have been able to
sustain their rights under it that they owe their
commanding position to-day in the realm of wireless
telegraphy.
The Receiving Apparatus also consists of a separate
local circuit which can be coupled when desired to
the antenna circuit through a transformer. The same
simple tuning arrangement is made to affect this
circuit also, so that the " multiple tuner," as the
instrument is called, controls all the circuits both for
sending and for receiving. The oscillations caused
in the antenna circuit by the action upon it of the
etherial waves flowing from the distant transmitting
station pass through one winding of the transformer
and thereby induce similar oscillations in the local
receiving circuit which are made perceptible by the
receiving instrument.
Reference has already been made to the original
form of receiving apparatus called the Coherer. This,
however, has been very largely superseded by the
Magnetic Detector of Marconi and the Crystal Detec-
tor, both of which make the signals perceivable as
buzzing sounds in the telephone.
The magnetic detector owes its existence to the
fact that oscillations tend to destroy magnetism in
iron. It is believed that every molecule of iron is
itself a tiny magnet. If that be so one would expect
every piece of iron to be a magnet, which we know it
is not. We can always make a piece of iron into a mag-
net by putting another magnet near it, but when we
take the other magnet away the iron loses its power,
R 257
WIRELESS TELEGRAPHY IN WAR
or to be precise it almost loses it. A piece of even the
best and softest iron having once been magnetized
retains a little magnetic power which we call " resi-
dual " magnetism.
All this is easily explained if we remember first
that a heap of tiny magnets lying higgledy-piggledy
would in fact exhibit no magnetic power outside the
heap. If, however, we brought a powerful magnet
near them it would have the effect of pulling a lot
of them into the same position, of arranging them in
fact so that instead of all more or less neutralizing
each other they could act together and help each
other. Then the heap would become magnetic.
On removing the powerful magnet, however, a lot
of the little ones would be sure to fall down again
into their old places and so the heap would at once
lose a large part of its power, yet some would remain
and so it would retain a certain amount of " residual "
magnetism. If, then, you were to give the table on
which the little magnets rest a good shake, the
" higgledy-piggledyness " would be restored and even
the " residual " magnetism would vanish.
So we believe that the little molecules lie just any-
how, wherefore they neutralize each other and the
mass of iron is powerless. When another magnet
comes near, however, they are more or less pulled
into the right position and the iron becomes mag-
netized. When the magnet is removed the magnetism
which it produced is largely lost, and if last of all we
give the iron a smart blow with a hammer even the
residual magnetism vanishes too.
Now, oscillations taking place in the neighbour-
258
WIRELESS TELEGRAPHY IN WAR
hood of a piece of iron possessing residual magnetism
have much the same effect as the blow of a hammer.
Probably because of its rapidity an oscillating current
shakes the molecules up and strews them about at
random, entirely destroying any orderly arrangement
of them. And Marconi used that fact in detecting
oscillations.
Two little coils of wire are wound together, one
inside the other. Through the centre of the inner-
most there runs an endless band of soft iron wire.
Stretched on two rollers this band travels steadily
along, the motive power being clockwork, so that it
is always entering the coil at one end and leaving it
at the other. As it travels it passes close to two
powerful steel magnets, so that as it enters the coil
it is always slightly magnetized. The oscillations
are passed through one of the two concentric coils,
and their action is to remove suddenly the residual
magnetism in that part of the moving wire which is
at the moment passing through. That sudden de-
magnetization then affects the second of the concen-
tric coils, inducing currents in it, not of an oscillating
nature but of an ordinary intermittent kind which
can make themselves audible in a telephone which is
connected with the coil.
This arrangement, then, causes the oscillations,
which will not operate a telephone, to produce other
currents of a different nature which will.
The reason why oscillations have no effect in a
telephone is no doubt because they change so rapidly,
at rates, as has been mentioned already, of the order
of a million per second. The telephone diaphragm,
259
WIRELESS TELEGRAPHY IN WAR
light and delicate though it is, is far too gross and
heavy to respond to such rapidly changing impulses
as that. In the magnetic detector the difficulty is
overcome by making them change the magnetic con-
dition of some iron wire which change in turn pro-
duces currents capable of operating a telephone.
The Crystal Detector achieves the same result in
another way.
There are certain substances, of which carborundum
is a notable example, which conduct electricity more
readily in one direction than the other. Most of these
substances are crystalline in their nature, and hence
the detector in which they are used gets its name.
Carborundum, by the way, is a sort of artificial
diamond produced in the electric furnace and largely
used as a grinding material in place of emery.
It is easy to see that by passing an oscillating
current, which is a very rapidly alternating current,
through one of these one-direction conductors one
half of each oscillation is more or less stopped. Oscil-
lations, again, are surgings to and fro : the crystal
tends to let the " tos " go through and to stop the
" fros." That does not quite explain all that happens.
It is not fully understood. The fact remains, however,
that by putting a crystal in series with the telephone
the oscillations become directly audible. The term
" in series with " means that both crystal and tele-
phone are inserted in the local receiving circuit so
that the currents in that circuit pass through both
in succession.
The resistance of the crystal being very great, a
special telephone is needed for use with it. It is quite
260
WIRELESS TELEGRAPHY IN WAR
an ordinary telephone, however, except in that it is
wound with a great many turns of very fine wire and
is therefore called a high-resistance telephone.
Whichever of these detectors be used, then, the
operator sits, with his telephone clipped on to his
head, and with his tuner set for that wave length at
which his station is scheduled to work, listening for
signals. He may go for hours without being called
up, and in the meantime he may hear many signals
intended for others. He knows they are not for him,
since every message is preceded by a code signal in-
dicating to whom it is addressed.
Under the conditions of warfare there is far more
listening than there is sending, but when a station
wishes to send the operator just switches over, cutting
out his receiving apparatus and bringing his trans-
mitting instruments into operation, and, having
adjusted his tuner for the wave length of the station
to which he desires to communicate, he flings out his
message.
In war-time, too, there is much listening for the
signals of the enemy, which is the reason why as few
messages are sent out as possible. In this case the
man sits with his telephone on his head carefully
changing his tuner from time to time in the
endeavour to catch any message in any wave-length
which may be travelling about. This searching the
ether for a chance message of the enemy must be at
times a very wearisome job, but it must be varied
with very exciting intervals.
On aircraft it is clear that no earth connection is
possible. The antenna in that case usually hangs
261
WIRELESS TELEGRAPHY IN WAR
vertically down from the machine or airship. Under
these conditions the valuable effect of the earth con-
nection is of course lost. As will be remembered, the
earth-connected apparatus sends forth waves which
cling more or less to the neighbourhood of the earth's
surface, while those from the non-earthed apparatus
as used by aircraft tend to fly in all directions. The
latter apparatus is in fact almost precisely similar to
that which Hertz used in his first experiments. Hence
the range is comparatively poor under these condi-
tions, but it is good enough for very valuable work
in warfare. Communication between airman and
artillery by this means has revolutionized the handling
of large guns in the field.
To save the airman from the accidental catching
of his aerial wire in a tree or on a building there is
sometimes fitted a contrivance of the nature of wire-
cutters so that he can at any moment cut himself
free from it.
So far we have dealt almost exclusively with the
naval and aerial use of this wonderful invention. It
is employed, though in a lesser degree, in land war-
fare. In such cases the aerial may be merely a wire
thrown on to and caught up on a high tree. More
elaborate devices are used, however, such as a high
telescopic tower similar to the tall fire-escape ladders
of the fire-brigades. Anyone who has seen the ladders
rush up to a burning building and commence to
erect themselves almost before they have stopped
will realise how valuable such a machine must be for
forming a temporary and easily movable wireless
antenna. The power which causes the tall tower to
262
WIRELESS TELEGRAPHY IN WAR
extend itself erect in a few seconds is compressed air
carried in cylinders upon the machine, while the
power which takes it from place to place is a petrol
motor, and since the latter can be made to re-charge
the storage cylinders it is clear that in it we have a
marvellously convenient adjunct to the wireless
apparatus.
But apart from such carefully prepared devices the
men of the Royal Engineers are past masters in the
art of rigging up, according to the conditions of the
moment, all sorts of makeshift apparatus whereby
signalling over quite long ranges can be carried on by
" wireless." Such improvisations, could they be
recorded, would constitute war inventions of a high
order.
263
CHAPTER XXII
MILITARY TELEGRAPHY
TELEGRAPHY plays a very important part
in warfare. The commander of even a
small unit cannot see all that his men are
doing or suffering, but is kept posted by telegraph or
telephone, while communication between units de-
pends very largely indeed upon such means. Wire-
less telegraphy, in land warfare, is largely devoted
to communication between aircraft and the artillery
batteries with which they are working, and to avoid
interference with that important work telegraphy
by wire is employed for most other purposes.
Right at the front this communication is kept up
by means of that type of instrument which the soldiers
call a " buzzer," for the good and sufficient reason
that that is really what it does.
In view of the fact that soldiers speak of their
home-land, for which they are enduring all manner
of risk and hardship, and to which they are longing
to return, by the contemptuous-sounding name of
" Blighty," we might expect that what they call a
buzzer has nothing whatever to do with making sound,
but in this case the name describes the thing very
aptly. Its sole purpose and intent is to make buzzing
sounds of either long or short duration.
264
MILITARY TELEGRAPHY
Perhaps the simplest way in which I can describe
this useful and interesting invention is by telling you
how you can make one for yourself. It is nothing
more than an electric-bell mechanism connected up
in a certain way.
As most people know, an electric bell contains a
magnet made of two round pieces of iron placed
parallel and yoked together at one end by means of
a third piece of iron, generally flat, while on to each
round piece is threaded a bobbin of insulated wire.
The iron becomes a magnet when, and only when,
current flows through the wire.
Near the free ends of the round pieces, or the poles
of the magnet, to use the orthodox term, is placed
another little piece of iron called the armature,
carried upon a light spring. When the current flows
in the wire the armature is pulled towards the poles
against the force of the spring, but when the current
ceases the magnet lets go and the armature, urged by
the spring, swings back again.
Behind the armature is a little post through which
passes a screw tipped with platinum, and in operation
this screw is advanced until its point touches a small
plate of platinum carried by the armature. Connec-
tion for the current is made to this " contact screw "
whence it passes to the armature, through the spring
to the wire upon the magnet, through that and away.
On completing the circuit, then, as when you push
the button at the front door, current flows and ener-
gizes the magnet. A moment later, however, the
armature moves, breaks the contact with the screw
and stops the current. Then the magnet lets go and
265
MILITARY TELEGRAPHY
the armature springs back, making contact once more
and setting the current flowing again. These actions
repeat themselves over and over again quite auto-
matically, and the hammer which is attached to the
armature vibrates accordingly.
That is the ordinary familiar electric bell. Cut
off the hammer and you have a buzzer with which
excellent telegraph signals can be sent.
So much for the sending apparatus. The receiving
device is simply an ordinary telephone receiver.
There is sometimes a little confusion in people's minds
because of this. A telephone is used, but it is used as
a telegraph instrument. The sounds heard in it are
not speech but long and short buzzing sounds which,
being interpreted according to the code of Morse,
deliver up their message.
Now the telephone, by which term is always meant
the receiver (the sending part of the telephone ap-
paratus being a " microphone "), is one of the most
remarkable pieces of electrical apparatus which the
mind of man has ever conceived. It is astonishingly
robust. With ordinary care you cannot damage it.
There is no need whatever to keep it wrapped in
cotton wool or even to keep it in a case. Without
harm you can put it loose in your pocket. Within
reason you may even drop it a few times without
harm. Its cost is only a few shillings. Yet its sen-
sitiveness is simply astounding. It will detect the
existence of currents so small that any other type
of instrument to deal with them has to be extremely
delicate and costly.
It consists of a magnet fitted into a little brass
266
MILITARY TELEGRAPHY
with a little piece of soft iron fixed on each pole,
while each of these " pole-pieces " is surrounded by
a tiny coil of wire. The lid of the box is a disc of thin
sheet-iron, and things are so proportioned that the
pole pieces nearly but not quite touch this sheet-iron
" diaphragm."
An outer cover, generally of ebonite, serves to
catch the sound-waves caused by any movement of
the diaphragm and convey them to the ear.
The action of the permanent magnet tends to pull
the diaphragm inwards to bulge it in slightly so
that it is in a state of very unstable equilibrium.
Because of this instability a very tiny current flowing
through the coils and either adding to or subtracting
from the strength of the magnet is sufficient either to
draw it still closer or to let it recede a little. Whether
it approaches or recedes depends upon the direction
of the current through the coils and makes no differ-
ence to the sound. The movement of the diaphragm
is great or small according as the current is strong or
weak : any variation in the current causes a perfectly
corresponding movement in the diaphragm. Even
those very small and very complex changes in air-
pressure which give us the sensation of sound are
very faithfully followed by this simple bit of sheet
iron, so that the sounds are faithfully reproduced for
our benefit. At the moment, however, we are not
dealing with speech but with buzzing sounds, which
are very simple, being merely a rapid succession of
" ticks."
The telephone, it must be remembered, takes no
notice of a steady current, except when it starts and
267
MILITARY TELEGRAPHY
stops. But each time that occurs it gives a tick.
Hence, if we start and stop a current very rapidly,
or to use another term, make it rapidly intermittent,
we get a rapid succession of ticks, and if rapid enough
they form a humming, buzzing, or singing sound.
If very fast you can get a positive shriek. The pre-
cise character of the sound depends entirely upon the
rapidity of the intermittency.
Now it is easy to see that the current passed through
an electric-bell mechanism is intermittent. It is the
very nature of the apparatus to make the current
intermittent. It is by so doing that it works. There-
fore, if we pass the same current which works a bell
through a telephone we get a buzzing or humming
sound according to the speed of interruption.
The vibration of the armature itself also causes a
humming sound of a similar note or tone to that heard
in the telephone, but it must be clearly understood
that these two sounds are quite different. One is
the result of mechanical motion, the other is the result
of electrical action producing motion in the diaphragm
of the telephone. When you listen in the telephone
it is not that you hear the sound of the bell mechanism,
you hear another sound altogether, although, since
both have the same origin, both have the same note
or tone.
Take any old bell, then, which you may happen to
have or be able to procure and an old telephone such
as can be bought for a shilling or so at a second-hand
shop, and these together with a pocket-lamp battery
can be formed into a military field telegraph.
The way to connect these up is to run a wire from
268
MILITARY TELEGRAPHY
one of the copper strips on the battery to one of the
terminal screws on the bell, a second wire from the
other screw on the bell to one of the flexible wires of
the telephone, which may be a mile away if you like,
a third wire returning from the other flexible wire
of the telephone back to the battery. To send signals
all you have to do is to touch the return wire upon
the second strip of the battery for short or long inter-
vals, thereby making the dot-and-dash signals. Or
a simple form of key can easily be contrived for the
purpose.
Every time you complete the circuit the buzzer
will buzz, in other words, it will permit an inter-
mittent current to pass round the circuit and a
buzzing or humming sound will be heard in the tele-
phone, no matter how far away it may be.
This arrangement, however, involves two wires
between the two stations, and in practice only one
is usual. This could be arranged by running the
third wire from the telephone not back to the send-
ing station but to a peg driven into the earth, con-
necting the second pole of the battery in like manner
to an earth pin at the sending end. Thus the return
wire would be done away with and the earth utilized
instead. To do that, unfortunately, you would need
to increase very greatly the power of your battery,
for although the path through the earth itself offers
practically no resistance at all to the current, the
actual places where the current passes to earth and
from earth, especially if they be simply temporary
pegs driven into the ground, offer very considerable
resistance, so that in order to get enough current
269
MILITARY TELEGRAPHY
through the buzzer to make it work would need a
powerful battery. There is another way, however,
by which that difficulty can be overcome quite easily.
Probably all my readers know something of the
induction or shocking coil, wherein intermittent
currents in one part of the coil induce intermittent
currents of a somewhat different kind in another
part of the coil. Few people realize, however, that
the same effect can be attained, within limits, in a
single coil such as the winding upon the magnet of
an electric bell.
Watch a bell at work and you will notice a bright
spark at the place where the contact is made and
broken. That spark is due to a sudden rush of current
which takes place in the coil when the original current
is stopped, in other words, when the contact is broken.
It is as if the coil gives a rather vicious " kick " every
time the current is stopped. There is not much elec-
tricity in this " kick " current, but it is very forceful,
and it is that force which makes it actually jump
across the gap after contact has been broken, thereby
causing the spark.
Now we can capture most of that energy and make
it go a long distance through wire and through earth
carrying our messages for us. To do this we need to
make a new connection on the bell at the place where
the spring is fixed. Then we can make two circuits.
One is between the two terminal screws of the buzzer,
in which circuit we must include the battery and the
key. That circuit will be just as it would be if we
were fixing the buzzer to announce our visitors at
the front door.
270
MILITARY TELEGRAPHY
The second circuit is different : lead one wire from
the new connection just made and take it to a pin
driven into the ground. If the ground is just a shade
moist a wire meat-skewer will answer admirably.
Then lead a second wire from that one of the two
terminal screws which is connected directly to the
winding of the magnet (not to that one which is
connected to the contact screw) and lead it away to
your distant station.
At the other station connect the single wire to the
telephone as before and the other " end " of the tele-
phone to a pin in the earth. You will find that the
" kicks " from the coil will traverse wire and earth-
return quite easily, while there will be no difficulty
about working the bell, for the small battery will do
that quite well. In fact, after cutting the hammer
off and so converting a bell into a buzzer, I have got
quite good results with one-third of a pocket-lamp
battery. The little flat batteries so familiar to us all
if divested of their outer covering will be found to
consist of three little dry cells any one of which is
quite capable of sending messages in the way de-
scribed as far as any amateur is likely to want to send.
To be able to send and receive at either end
it is only necessary to connect both telephones and
both coils "in series." That is to say, connect one
end of the coil to the long wire and the other to one
wire of the telephone, the other wire of the telephone
being connected to earth. If this be done at both
ends signals can be sent and received both ways.
Many young readers, scouts, members of cadet
corps and the like, will find great pleasure and in-
271
MILITARY TELEGRAPHY
terest in constructing and working this apparatus,
besides which it shows precisely what the official
" buzzer " is like.
Although beautifully made, of course, the army
instrument is essentially just that and little more.
It has an additional feature, however, namely, a
microphone, so that when desired it can be used as
a speaking telephone for transmitting verbal mes-
sages. It also has the bottom of the case made of a
brass plate so that earth pins are often unnecessary,
the case dumped down upon the ground being a good
enough " earth."
Buzzers are not used for very long lines : forty
miles is about the limit, and usually the distances
are very much less. That is because long lines rather
object to rapidly changing currents flowing through
them. Why, you say, what currents could change
more rapidly than telephone currents carrying speech,
yet they go for hundreds of miles ? True, but in that
case there are two wires, flow and return, twisted
together all the way, under which conditions they
interact upon each other in such a manner as to
abolish the difficulty to which I am referring. Buzzers
and indeed all the telegraph circuits consist of one
wire and the earth, which is quite different.
Another objection to the buzzer is that it is apt to
interfere with others. For instance, if two buzzer
sets are at work anywhere near each other and the
wires run parallel for a distance they will be able to
hear each other's signals as well as their own. If two
such sets are earthed near together the same thing
happens, the signals of one are picked up by the
272
MILITARY TELEGRAPHY
other, a very annoying state of affairs for the opera-
tors.
Right at the front, however, amid the rough and
tumble of the actual fighting, the buzzer is supreme.
The wire used is sometimes plain copper enamelled :
more often, however, it is a mixture of steel and
copper strands twisted together and covered with a
strong insulating covering. This is carried on reels
in properly fitted carts which can advance at a gallop,
paying out the wire as they go. The inner end of
the wire is connected to the axle of the reel in such
a way that a telegraphist in the cart is in communi-
cation all the time with the starting-point, the wheels
of the cart providing him with an earth connection.
When laying these wires another interesting little
device is often used an earth plate on the operator's
heel. Thus, while carrying the wire along, laying it
as he goes, he can still be in communication with the
starting-point every time he puts his heel to the
ground.
For the longer lines away back from the fighting
the methods employed are just the same as those of
peace. " Sounder " instruments are used, Wheatstone
automatic machines, duplex and quadruplex systems,
whereby two and four messages are sent simultaneously
over the same wire, indeed all the contrivances and
refinements of the home telegraph office are to be
found in the field telegraph offices. But it would
hardly be fitting to describe them here. Some in-
formation on the subject will be found in " The Ro-
mance of Submarine Engineering," where their appli-
cation to cable telegraphy is dealt with.
s 273
MILITARY TELEGRAPHY
A genuine speciality of warfare, however, is the
methods by which makeshift arrangements can be
set up, such as sending telegraph messages over a
telephone wire without interfering with the latter.
Imagine that A and B are the two wires of a tele-
phone circuit running (for the sake of simplicity) from
north to south. At the south end I connect a tele-
graph set to both wires while you, we will imagine, do
the same at the north end. You and I can then
signal to each other without the telephone man hear-
ing us at all. To him the two wires are flow and re-
turn, to us they are both " flow," the earth being our
return. Thus our signals never reach his instruments
at all. But when we each connect to both his wires,
do we not " short-circuit " or connect them to each
other, thereby destroying his circuit ? No, we are
too cunning for that. We first connect the two wires
A and B together with a coil of closely wound wire,
having, in scientific language, much "inductance," and
telephone currents shun a coil of that sort. Then we
make our connection to the centre of that coil so
that our currents go to A through half the coil and
to B through the other half. This enables us to use
the apparatus without interfering with the other
fellow at all. For this, by the way, we must use
ordinary telegraph instruments. We cannot employ
a buzzer, for these coils which we use to obstruct the
passage of the other man's telephone currents would
also obstruct the changing currents from a buzzer.
The slow, steady currents of the ordinary telegraph
pass quite easily, however.
Again, suppose you and I want to communicate
2'/4
MILITARY TELEGRAPHY
by buzzer and there is already a wire laid passing
both of us but in use already for ordinary telegraphy.
We only need to add a " condenser " to our apparatus
and we can manage all right. As a matter pf fact,
the service instruments generally have condensers
partly for this very purpose. Each of us then con-
nects his instrument to the wire and to earth, after
which we can signal to each other while the telegra-
phist is unaware of the fact. The reason that is
possible is the reverse of what we saw just now.
There we had a coil which obstructed buzzer or tele-
phone currents but passed ordinary telegraph cur-
rents. Here we use condensers which will pass our
buzzer currents but not the ordinary telegraph
currents.
Thus the soldier telegraphist is up to many dodges
whereby he can save time or save material, both of
which may be precious. As in bridge building and
other branches, he needs to be quick to adapt him-
self to circumstances, to utilize to the full any oppor-
tunities which may present themselves. But his
principles are quite simple and do not differ in any
way from those of peace. It is only in applying them
that the differences arise.
275
CHAPTER XXIII
HOW WAR INVENTIONS GROW
THE inventor of one of the devices described
later on in this book modestly claims that
he did not invent it but it invented itself.
What he means is that he worked step by step, from
simple beginnings, each step when complete suggest-
ing the next. To put it another way, many inventions
grow in the inventor's mind, sometimes from un-
promising beginnings, the most unlikely start often
resulting in the most successful ending.
Who has not heard of the " tanks " which made
such a name for themselves when they suddenly
appeared in Northern France ? The British Com-
mander-in-Chief simply mentioned that a new type
of armoured car had come into use with good results,
but the newspaper men set the whole non-Teutonic
world laughing with droll stories of huge monsters
suggestive of prehistoric animals which suddenly
began to crawl through the slime and mud of the
battle-field, pouring death and destruction upon the
astounded Germans.
How they came to be called tanks no one seems to
know clearly but that is how they will be known for
all time. It has been suggested that they were so
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HOW WAR INVENTIONS GROW
named because tank is one of the things which they
certainly are not, the intention being thereby to add
to the mystification of the enemy. That is by the way,
however, for we are more concerned with the things
than with their name.
Their precise origin is wrapped in mystery but we
have it on excellent authority that they grew out of
the peaceful " tractor," originally intended to drag a
plough to and fro across a field in the service of the
farmer. An illustration of one of these interesting
machines will be seen in this book which will well
repay a little study.
It consists of a steel frame or platform upon which
is mounted a four-cylinder petrol engine with a
reservoir above to carry the supply of fuel and with
a radiator in front to cool the water which keeps the
engine from becoming too hot. Towards the back of
the vehicle is what is called by engineers a worm-
gear, the function of which is to reduce the one
thousand revolutions per minute of the engine to
somewhere near the slow speed required of the
wheels of the tractor.
This worm-gear is simply a wheel with suitable
teeth on its edge in conjunction with a screw so
made that its thread can engage comfortably with
the teeth. This latter, because of the wriggling
appearance which it presents when it is revolving is
called a worm, which name it gives to the whole
apparatus. Both wheel and worm are mounted in
bearings which form part of a case enclosing the
whole so that dirt is excluded while, the case being
filled with oil, ample lubrication is assured. The
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HOW WAR INVENTIONS GROW
shafts of both wheel and worm emerge through holes
in the case.
It will easily be seen that each single turn of the
worm will propel the wheel one tooth, so that if the
wheel have fifty teeth, for example, the worm will
turn fifty times to the wheel's once. Thus a great
reduction in speed is attainable with this device and
what is equally valuable, a great increase of power
also results. Thus a small engine, working at a high
speed, is able by means such as this to pull very heavy
loads at a slow speed.
It is evident, however, that the reduction necessary
in this case cannot be attained even by a worm-gear,
for there are other wheels visible which show that
ordinary tooth gearing is also employed to reduce the
speed even further before it is applied to driving the
tractor along. Practically all the other gear which we
see in the picture, above the platform, consists of the
controlling apparatus.
The object with a screw-like appearance just
behind the engine is not really a screw but is a
flexible coupling joining the engine to the worm-
gear, its " flexibility " enabling the two to work
sweetly together even though by chance they may
get just a little out of line with each other.
But by far the most interesting part of the machine
is that which is underneath the frame. At one end we
see a pair of ordinary-looking wheels and between
them the gear for swinging them to right or left for
steering purposes, but even they are somewhat
unusual, since they will be seen to have flanges or
rims round the edge for the purpose of biting into
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HOW WAR INVENTIONS GROW
the earth, so that they may be able to guide the
machine the better in soft ground.
The back wheels, however, are quite peculiar, for
there is a pair on each side and round each pair is a
chain somewhat after the fashion of a huge bicycle
chain. The links of this chain are made of tough
steel and they are two feet wide, so that each chain
forms a broad track upon which the machine moves.
The links of this track-chain will be seen to be tooth-
shaped so that they grip or bite deeply into the
yielding ground. The teeth, moreover, are shaped
like those of a saw and they are so placed as best to
help the tractor forward.
Between the two chain-wheels will be noticed a row
of smaller wheels and it is these which largely support
the weight of the machine, the chains forming tracks
upon which they run.
The wheels actually turned by the power of the
engine are the chain-wheels, and their action is such
as to keep on laying down and then taking up again
two broad firm tracks along which, at the same time,
they keep propelling the other wheels which carry
the weight above. The effect, really, is just as if the
machine had a pair of driving wheels two feet wide
and of enormous diameter, of such diameter, in fact,
that the part in contact with the ground is almost
flat. Thus there is always a broad bearing surface to
prevent sinking in soft earth, while the tooth-like
shape of the links gives a firm hold even under very
adverse conditions.
This form of construction has been used for some
few years now under the name of " caterpillar " or
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HOW WAR INVENTIONS GROW
"centipede" traction. A glance at the picture will
explain those names, particularly if the chain-driven
part of the vehicle be imagined to be a little longer
than it is in the particular machine shown.
The idea of armouring a vehicle with bullet-proof
plates is also a fairly old conception. Armoured
trains were used again and again during the South
African War, and armoured motor-cars became
familiar to most people. In the case of cars, how-
ever, the armour could only be very light and the
guns carried were limited practically to a single
machine-gun and some rifles. Moreover, the opera-
tions of a car are very largely confined to such places
as are blessed with good roads or smooth plains. An
armoured car of the older type would have cut a poor
figure amid the shell-holes and mine-craters of
Northern France. It would have had to keep to the
roads and so it was little used.
But the idea of an armoured vehicle was good and
a good idea is never entirely lost. Sooner or later
some genius puts it to good use. Thus the idea of an
armoured vehicle came to be associated with the
idea represented in the centipede tractor and the
result was the tank.
Why not armour a large centipede, said someone ?
Make it very big and strong. It will trample down
the barb-wire entanglements as if they were grass.
If made long enough and rightly balanced it will pass
over the trenches like a moving bridge. Nothing but
a direct hit from a heavy gun will do it much harm.
For, observe, the mechanism can be entirely covered
up, all the vital parts can be well protected, and the
280
* "8
5 1
a *
HOW WAR INVENTIONS GROW
chain tracks can be so strong as to be almost im-
damageable.
Thus we get a glimpse of the growth of this simple
peaceful agricultural machine into one of the most
striking mechanical achievements of the Great War.
Another thing which seems to have grown more or
less of itself is the bomb or grenade. Before the time
of modern accurate fire-arms hand-grenades were
quite a recognized weapon. The " Grenadier "
Guards owe their title to this fact and carry the
design of a bursting grenade upon their uniforms.
Yet until a few years ago everyone thought that
such things were done with for ever : that with
modern rifles soldiers would seldom get near enough
together to use grenades and that if they did the
bayonet would be the weapon to be used.
When, however, the Germans were driven back at
the battle of the Marne and found themselves com-
pelled to entrench in order to avoid further disaster,
it soon became evident that neither rifle nor bayonet
nor both together entirely filled the needs of the
infantryman.
Since the Allies were not powerful enough to drive
the Germans from their trenches forthwith, they,
too, had to entrench. Gradually the trenches drew
nearer and nearer together and at the same time
skill in entrenching increased. Thus a time soon
arrived when both rifle and bayonet were largely
useless for purposes of offence. Then the hand-
grenade came into its own again, for the men could
throw it from the depths of their own trench high
into the air in the hope that it would fall into the
281
HOW WAR INVENTIONS GROW
trenches of the enemy. The call for these quickly
produced the supply. There is little need to describe
them here, for who among us has not intimate friends
who used them again and again ? This much may be
said, however. They were little hollow balls of cast
iron, sometimes chequered so that when they burst
they flew into many fragments. Inside was a charge
of explosive with a suitable fuse or firing mechanism.
Some were fixed to the end of a stick for convenience
in throwing, while others were simply handled like
a cricket-ball.
They serve to show us, however, how an old idea
may under fresh conditions be revived into what is
practically a new invention.
Another example of the same sort is the revival of
chain mail. Who, but a few years ago, would have
thought it possible that modern soldiers would go
to battle sheathed in shirts consisting of little metal
plates cunningly connected by wire links and so
overlapping each other as to form a perfect shield for
all the more vital parts of the body ? To what extent
these were worn I do not know, for the British
soldier is a very shy fellow in some ways and there
are few who would not be a trifle ashamed to let their
comrades see them thus garbed. They would feel
that it was a confession of fear, and however afraid an
Englishman may be he will never admit it. He is
really a pious fraud, for the more he is really afraid
inwardly the more courageously will he act just to
hide his fear.
Since, however, the bullet-proof helmet is worn
officially nowadays there seems no reason whatever
282
HOW WAR INVENTIONS GROW
why the bullet-proof waistcoat should not be adopted
officially too. It is very light and very flexible and
it is claimed that it is quite effectual in stopping rifle
and machine-gun bullets.
Thus we see in what different ways inventions
grow. Some are warlike from first to last, like the
gun and the torpedo, but we find a vast range of
peaceful things growing into implements of warfare,
as the farmer's tractor has been developed into the
tank, while not less interesting are the old ideas
revived and adapted to modern needs, exemplified
by the hand-grenade and the chain armour.
283
CHAPTER XXIV
AEROPLANES
OF all the great inventions perhaps the most
striking because of the suddenness with
which they have come upon us are those
relating to the navigation of the air. Until
a few years ago "to fly " was taken to typify the
impossible. Now we see men flying every day and
there is scarcely anyone who has not had a friend or
relative in the Flying Corps.
Recent experience, too, has shown that this one
invention has revolutionized warfare in several
important departments, particularly in the use of
very heavy long-range artillery. Huge guns, hidden
in a hollow or behind a hill, have been set to throw
shells on to an unseen target, while a man in an aero-
plane above watches the result and signals back by
wireless. Thus by the aid of aircraft the power of
artillery has been immensely increased.
Again, aircraft have superseded cavalry for recon-
naissance purposes, that is to say, for finding out the
enemy's strength and preparedness. Only a few
years ago a General who needed information as to his
foe would send forward a screen of cavalrymen who
would cautiously creep forward until, judging by
what they could see and by what sort of a reception
284
AEROPLANES
they got, they were able to form some idea of the
foe's arrangements. Nowadays, however, the airmen
sail over his head and take photographs of him and
his positions. A careful commander to-day not only
screens his men and his guns from view along the
land but he also tries his best to make them invisible
from above. And, speaking of inventions, the
soldiers have shown a degree of ingenuity in making
themselves and their guns invisible which almost
merits a volume to itself.
The airman, therefore, goes up and sails over the
enemy. He may be simply observing for some
particular unit of artillery, or he may be sent to find
out things generally nothing in particular, but
anything which seems likely to be of use. He looks
out intently and carefully, moreover he not only
looks with his own eyes : as has just been mentioned,
he takes photographs, which can be developed on his
return and studied minutely at leisure. He may, or
may not, according to circumstances, send back
reports of an urgent nature by wireless tele-
graphy.
In some cases these duties are all carried out by
one man, but in others there are two : one the pilot
who looks after the working of the machine, and the
other the observer whose whole attention can thus be
devoted to scrutinizing the enemy.
Of course, when aeroplanes go on scouting ex-
peditions like this they are apt to be attacked by
the enemy both by anti-aircraft guns and also by
other aeroplanes. The former can only be met by
high speed and the steering of a somewhat erratic
285
AEROPLANES
course so as to confuse the gunners and prevent them
from taking good aim.
The other aeroplanes, however, must be met by
actual fighting. The only way to defeat them is to
go for them and attack them, a machine-gun being
the most usual weapon.
Besides those who go up for definite scouting
operations or to " spot," as it is termed, for the
artillery, there are other machines whose sole duty
is fighting. These go up for the purpose of driving
off those machines of the enemy which may come
prying, or to keep the ground, so to speak, for the
scouting machines and enable them to do their work
unmolested.
Then there are, of course, still others whose
function is to carry out bombing expeditions.
All these different duties call for different types of
machine, but I do not propose to go into the differ-
ences here since changes are so rapid in this par-
ticular field that only the general principles remain
unchanged for any length of time. What has just
been hinted, however, as to the different kinds of
work which the aeroplane is called upon to do will
enable the reader to see why different kinds of
machines are needed.
So far we have only spoken of aeroplanes. There
is a kind of machine sometimes called a hydroplane
but which we are gradually getting to call a sea-plane.
The latter term is much to be preferred, since the
former is also in use to denote a special kind of
high-speed boat.
Now a sea-plane only differs from an aeroplane in
286
AEROPLANES
that it has floats instead of wheels. The aeroplane
has wheels to enable it to alight upon and arise from
the ground : the sea-plane has floats by which it can
alight upon the water and arise from the water also.
In some instances this float idea is made so pro-
nounced a feature of the machine that it becomes a
flying boat.
Sea-planes are therefore really only aeroplanes
specially adapted for a certain purpose. They are
really just as much aeroplanes as those machines
which go by that name. It is somewhat unfortunate,
therefore, that a separate term is used to describe
them. But there it is : names grow in a very curious
way, not always in a logical way, and a name having
once stuck to a thing in the mind of the public it is
very difficult to make any alteration.
Aeroplanes, then, may be said to include a sub-
division known as sea-planes, and for the rest of this
chapter what is said of aeroplanes will apply to sea-
planes also.
Without doubt, these are the fastest vehicles in
existence. Many of them can exceed a speed of a
hundred miles an hour. Consequently, the pilot
lives while he is aloft in the equivalent of a furious
gale, and it would seem as if that must produce such
a degree of cold as to be almost unendurable. More-
over, it appears that this cold is almost as bad in
summer as in winter, for the temperature high up in
the air is much the same all the year round. The
consequent muffling up with thick clothes and gloves,
while it mitigates the cold, must add greatly to the
pilot's difficulties in managing his machine. The
287
AEROPLANES
protection for his eyes and ears which is made
necessary by the same conditions must likewise add
to his difficulties or at any rate to his discomfort. On
the other hand, the effect of gliding at a very high
speed over a perfectly smooth track, for that is in
effect what it is, is very exhilarating, which to some
extent compensates for the other drawbacks.
Moreover, the handling of such a machine in the
air, particularly if a fight is included in the pro-
gramme, appeals strongly to the sporting instincts of
young men, so much so that during the War, in spite
of the dangers and hardships, and the continual loss
of life, there was never a dearth of men anxious to
become pilots.
Owing to these considerations, too, it follows that
the best aviators are to be found in those lands
where the people are most devoted to sports. Hence,
as we have it on excellent authority, the young men
of Great Britain and the United States, with their
love of adventure and their strong sporting instincts,
make better men in the air than the Germans.
But really we are more concerned here with the
machines than with the men, so let us get back to our
subject.
The aeroplane consists of one or more "planes"
or surfaces which, on being held at a certain slant and
then pushed forward rise or remain supported in the
air. Therefore the plane or planes need to be
supplemented by first a tail and horizontal rudder to
hold them at the correct slant, and an engine and
propeller to drive them forward.
It is not necessary, here, to go over the history of
288
AEROPLANES
the aeroplane, as that has been told so often. It is
not of much interest, moreover, except to those who
are particularly concerned with small details of
construction, for in a general way the machine of
to-day is very little different from one pictured by
Sir George Cay ley a hundred years ago. It is only the
perfecting of the details which has transformed a
dream into a very real thing.
So we will look only at the construction of the
aeroplane in a general way, to do which we must
first consider why it flies at all. It is due to the well-
established law that action is always accompanied by
a reaction equally strong and in the opposite direction.
When a gun is fired the explosion not only drives the
shell forward but equally drives the gun itself back-
ward. The backward energy of the recoil is precisely
equal to the forward energy of the shell. The two are
equal but in opposite directions. In like manner a
rocket ascends because the hot gases from the paper
cylinder blow forcibly downwards, thereby producing
an equal reaction upwards.
Now the plane of a flying machine is held with its
forward edge a little higher than its rear edge, so that
as it is pushed along it tends to catch the air and
throw it downwards. Hence the reaction tends to
lift the plane upwards. When the machine starts the
reaction is not sufficient to overcome gravity, which
is trying to hold the machine down upon the ground,
but as the speed increases and the air is thrust down
with more and more violence the point is ultimately
reached when the reaction is able to overcome
gravity and the machine ascends.
T 289
AEROPLANES
When a sufficient height is reached, the pilot alters
the position of his horizontal rudder or " elevator "
so as to make the position of the plane more flat,
with the result that it throws the air downwards to a
less extent, and the reaction is thereby reduced until
it is only just sufficient to keep the machine at the
same height. To descend, the position of the plane is
made still flatter, the reaction is reduced still more
and gravity has its way once again, bringing the
machine to earth.
In other words, the machine acts under the influ-
ence of two forces : the downward pull of gravity
and the upward reaction due to the action of the
machine in thro whig the air downward. The former
never varies, the latter can be varied by the pilot at
will : he can increase it by increasing the speed or by
increasing the tilt of his plane or planes : he can
reduce it by diminishing the speed or the tilt. Since
generally speaking the speed of his engine will remain
constant, he rises, remains at the same height or falls,
at will, by the simple manipulation of the elevator
through which he can change the tilt or inclination.
Most machines have a fixed tail as well as a
horizontal rudder or elevator, the same being so set
that it tends to keep the plane in a certain normal
inclination, the elevator being called in to increase
that or diminish it as may be required.
In addition to the elevator there is also another
rudder of the ordinary kind, such as every ship and
boat has, for guiding the machine to right or left.
The elevator steers up and down, the rudder steers
to either hand.
290
AEROPLANES
Provision is also made for balancing the machine.
This is sometimes in the form of two small planes
hinged to the main plane, one at either end, connected
together and to a controlling lever by wires, so that
by their use the pilot can steer the right-hand side of
his machine upwards and the left-hand downward,
or vice versa, if through any cause he finds a tendency
to capsize.
In some machines the same effect is produced not
by separate planes but by pulling the main plane
itself somewhat out of shape, but precisely the same
principle is involved.
The planes are usually made with a slight curve hi
them, so that they may the better catch the air and
" scoop" it downwards, so to speak. They usually
consist of fabric specially made for the purpose,
stretched upon a light wooden framework. The
whole framework is usually of wood with metal
fittings frequently made of aluminium for the sake
of lightness.
The engines have been mentioned in another
chapter. The propeller which is almost invariably
fixed directly upon the shaft of the engine has two
blades only and not three as is usual with those of
ships. Precisely why this should be so is not clear,
but experience shows that two-bladed propellers are
preferable for this work. They are made of wood,
several layers being glued together under pressure,
the resulting log being then carved out to the
required shape. This makes a stronger thing than it
would be if cut out of a single piece of wood.
All parts, engine, elevator, rudder and balancing
291
AEROPLANES
arrangement, are controlled by very simple means
from the pilot's seat.
In monoplanes there is but one main plane,
resembling a pair of bird's wings. Or if we care to
look upon it as two planes, one each side of the
" body," then we must call it a pair. Since the
name " mono " indicates one it is best to think of it
as one plane although it may be in two parts. The
biplane has, as its name implies, two planes, but
in that case there can be no doubt, since they are
placed one above the other. Machines have been
made with three planes and even with as many as
five, but monoplanes and biplanes appear to hold
the field.
It is not possible for an aeroplane to be in any
sense armoured for protection against bullets : for
defence the pilot has to depend upon his own cunning
manoeuvres combined with the fast speed at which
he can move. For offensive purposes he usually has
a machine gun mounted right in front of him with
which he can pour a stream of bullets into an
opponent or even, by flying low, he can attack a body
of infantry. It is recorded that one German prisoner
during the war, speaking of the daring of the British
pilots in thus attacking men on foot, exclaimed,
" They will pull the caps off our heads next."
Some of the aeroplanes have their propeller behind
the pilot and some have it in front. The latter, to
distinguish them, are called " Tractor " machines,
since in their case the propeller pulls them along.
Now it is easy to see that a difficulty arises in such
cases through the best position for the gun being
292
AEROPLANES
such that it throws its bullets right on to. the pro-
peller. But that has been overcome in a most simple
yet ingenious way. The gun is itself operated by the
engine with the result that a bullet can only be shot
forth during those intervals when neither blade of the
propeller is in the way. The propeller is moving so
fast that it cannot be seen and the bullets are
flying out in a continuous rattle, yet every bullet
passes between the blades and not one ever touches.
It is easy to see that when an aeroplane is manned
by a single man, as is often the case, he must have his
hands very full indeed, what with the machine itself
and the gun as well. In fact, he often has to leave the
machine for a short time to look after itself while he
busies himself with the gun.
Now there we see a sign of the wonderful work
which has been done in the course of but a few years
in the perfecting of the aeroplane, the result of a
series of improvements in detail which make but a
dreary story if related but which make all the differ-
ence between the risky, uncertain machine of a few
years ago and the safe, reliable machine of to-day.
Modern machines are inherently stable. The older
ones had the elements of stability in them but they
were so crudely proportioned that these inherent
qualities did not have a chance to come into play.
If one drops a flat card edgewise from a height it
seems as if it ought to fall straight down to the
ground. Yet we all know from experience that it
seldom does anything of the kind. Instead, it
assumes a position somewhere near horizontal and
then descends in a series of swoops from side to side.
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AEROPLANES
There we see the principle at work which, in a well-
designed aeroplane, causes inherent stability. The
explanation is as follows.
The aeroplane is sustained in the air through the
upward pressure of the air resisting the downward
pull of gravity. That has been fully explained
already. Now gravity, as we all know, acts upon
every part of a body whether it be an aeroplane or
anything else. But for practical purposes, we may
regard its action as concentrated at one particular
point in that body, called the " centre of gravity."
Likewise, the upward pressure of the air acts upon
the whole of the under surface of the plane or planes,
yet we may regard it as concentrated at a certain
point called the " centre of pressure." Further, we
all know from experience that a pendulum or other
suspended body is only still when its centre of gravity
is exactly under the point of suspension. If we move
it to either side it will swing back again.
In just the same way, the only position in which
an aeroplane will remain steady is that in which the
centre of gravity is exactly under the point of
suspension or, in other words, the centre of pressure.
For the centre of pressure in the aeroplane is pre-
cisely similar to the point of suspension of a pendulum.
Let us, then, picture to ourselves an aeroplane
flying along on a horizontal course with this happy
state of things prevailing. Something we will suppose
occurs to upset it with the result that it begins to
dive downwards. It is then in the position of sliding
downhill and instantly its speed increases in con-
sequence. That increase of speed causes the ah* to
294
AEROPLANES
press a little more strongly than it did before upon the
front edge of the planes. In other words, the centre
of pressure shifts forward a little, with the result that
the centre of gravity is then a little to the rear of the
centre of pressure.
A moment's reflection will show that with the
centre of pressure (or point of suspension) in advance
of the centre of gravity there is a tendency for the
machine to turn upwards again, or, in other words,
to right itself.
If, on the other hand, the initial upset causes it to
shoot upwards the speed instantly falls off and the
centre of pressure retreats, turning the machine
downwards once more. And the same principle
applies whatever the disturbance may be. Instantly
and automatically a turning force comes into play
which tends to check and ultimately to correct
what has gone wrong.
This principle explains the behaviour of the card
dropped from an upstairs window and, no doubt, as
has been said, it operated also in the early flying
machines, but in their case other factors caused
disturbing elements with which the self-righting
tendency was not strong enough to cope. As time
went on, however, experience taught the makers how
to avoid these disturbing factors until at last the
self-righting tendency was able to act effectively,
thus producing the aeroplane which is inherently
stable and which will, for short periods at all events,
fly safely without attention from its pilot.
Each little improvement in this direction was an
invention. Of course, there were certain men whose
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AEROPLANES
names stand out prominently in the history of the
aeroplane, notable among whom are the Wright
brothers, but the final result is due to innumerable
inventions, many of them by unknown men.
But perhaps someone will say, how can you
possibly talk about final results in a matter which is
still in its infancy ?
The answer to that is that so far as the safe,
" fly able " machine is concerned, it has arrived.
Little now remains to be done in that direction.
Further improvements there will, of course, be, but
the great fundamental problems of flight have been
solved.
296
CHAPTER XXV
THE AERIAL LIFEBOAT
BALLOONS had not long been invented when
the idea arose of a device by means of which
an aeronaut who found himself in difficulties
might be able to reach the ground in safety. In other
words, the need was felt for something which should
play towards the balloon the part which the lifeboat
does to the ship.
The original idea of a parachute was even older
than that, since we are told of a man away back in
the seventeenth century who amused the King of
Siam by jumping from a height and steadying his
descent by means of a couple of umbrellas. It was
not, however, until the very end of the eighteenth
century or the beginning of the nineteenth that
descents were made from really considerable heights
from balloons.
The usual arrangement then was to have the
parachute hanging at full length fastened below the
basket, or tied to one side of the balloon in such a
manner that it could be detached by cutting the cords
that held it up. When the parachute was carried
below the balloon basket the man was already in the
cradle or seat of the parachute ready to be dropped,
but when the seat was tied to the side of the car of
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THE AERIAL LIFEBOAT
the balloon the aeronaut, when he wished to make a
descent, first got from the car into the seat, and,
casting himself adrift from the car, swung out from
under the centre of the balloon so that when he was
hanging clear another man in the balloon cut the
cords or pulled a slip-knot which set the parachute
free. There were different ways of doing this and
when a man was by himself he had to get into the
sling of the parachute and, on finding himself clear
of everything, he would give a tug to a cord which
would release a catch holding up the parachute and
allow it to drop to earth.
The parachute, at the very first, was but a simple
affair, being little more than a circular sheet of
cotton or similar fabric, but it was very soon found
necessary to make it a bag or it would not properly
hold the air. Cords were attached at regular
intervals all around the edge of this bag, these cords
being gathered together and attached to the edge of
a basket which carried the man. Sometimes only a
sling was used, or a simple light seat after the fashion
of the " bosun's chair " upon which a sailor is some-
times hauled to the top of an unclimbable mast, or a
steeplejack to the top of a chimney.
Thus, when it was dropped, the weight of the man,
pulling upon all the cords simultaneously, drew down
the edge of the bag, which, catching the air in its fall,
acted as a powerful brake and reduced the rate of
falling to such an extent that if all went well the man
alighted in safety if not comfort.
As has already been remarked in another chapter,
air, which seems to us sometimes to be so exceedingly
298
THE AERIAL LIFEBOAT
light as to have practically no weight at all, really
has weight and also the property which we call
inertia, by virtue of which things at rest prefer to stay
at rest.
Now when this open air-bag, of considerable area, is
pulled downwards it causes a very considerable
disturbance in the air. As it descends the air inside
and beneath it is first pushed downwards and com-
pressed a little, then it commences to move outwards,
towards the edge, round which it finally escapes to
fill the slight vacuum in the space just above the
descending parachute. All this the air objects to do
because of its inertia. The parachute has to force it
to act thus and in that way it uses up some of the
force of gravity which all the time is pulling the man
earthwards. In other words, that force, instead of
dragging the man downwards at such a speed as to
dash him to pieces, is so far employed in churning up
the air that what is left only brings him down quite
slowly and ends with just a gentle bump. That is the
scientific explanation of what happens, although
expressed in somewhat homely language.
To anyone who thinks of this matter it will be clear
that a relatively heavy weight like a man, suspended
from a parachute, is like a very delicately poised
pendulum, and consequently it is not surprising to
hear that the early parachutes oscillated very con-
siderably from side to side, so much so, indeed, that
this oscillation became a decided danger, for before
the proper shape of the air-bag was found out they
sometimes skidded and even turned inside out. It
was found, however, at quite an early stage that
299
THE AERIAL LIFEBOAT
this instability could be to some extent cured by
making a hole right in the centre or crown of the
parachute through which the air compressed inside
could blow upwards in a powerful jet. At first sight
it seems as if this would much weaken the parachute
and cause it to descend too quickly, but quite a large
hole can be safely made, and to make such a hole is
only the same thing as slightly reducing the area and
that can be easily remedied by slightly increasing the
diameter.
Reading of this many years ago, I have often been
puzzled as to why the presence of the hole should
have this steadying effect, the explanation given in
the old scientific textbook from which I learnt it
being obviously very unsatisfactory. Of recent
years, however, this subject of parachutes has been
very deeply studied by an eminent engineer of
London, Mr. E. R. Calthrop, the inventor of the
" Guardian Angel " parachute to which these re-
marks are leading up, and he has hit upon what is
undoubtedly the explanation. He says that the big
jet of air shooting upwards through the crown of the
parachute forms in effect a rudder which steers the
parachute in a straight downward course, just as the
rudder guides a boat upon the surface of the water.
It is quite possible that thus far the impression
conveyed to the reader's mind is that the parachute
and its use are very simple, straightforward matters.
One may be inclined to think that it is only necessary
to get a circular sheet of fabric, to fasten the cords to
it, to connect them to a suitable seat and then to
descend from any height at any time in perfect
300
THE AERIAL LIFEBOAT
safety. If you make a model from a flat sheet of
cotton, then one made like a bag, and drop them
with little weights attached from the top window of
your house you will see what funny things the air
can do. After having tried these little ones, you will
begin to suspect that the big parachute is full of
waywardness : and, as a matter of fact, until recent
years, it has been very largely a delusion and a snare.
By its refusal to act and open at the right moment it
has sacrificed many lives. Although apparently so
simple, there were conditions existing and forces at
work which for a century or more had never been
properly considered and investigated, and it is only
now that we have arrived at a parachute whose
certainty of action and general trustworthiness
entitle it to be called the " lifeboat of the air."
The troubles with the older parachutes were two.
First, although often it opened quite quickly, and
carried its load as perfectly as could be desired, it
sometimes had the habit of delaying its opening, and
unless the fall were from a very great height it was
unsafe to take the risk, indeed, it sometimes refused
to open at all, and the poor parachutist suffered a
fearful death. It had to be carried in a more or less
folded-up state. Often it was hung up by its centre
to the side of a balloon, when it was very like
a shut-up umbrella. Consequently the power of
opening quickly and certainly was of the first import-
ance, and the lack of that power and the uncertainty
of its action were a very serious defect. It has
always suffered from an ill reputation as to relia-
bility.
301
THE AERIAL LIFEBOAT
The second fault lay with the cords. They would
persist in getting entangled. Everyone knows how a
dozen cords hanging near together will get entangled
with each other on the slightest provocation. Such
cords if blown about by a strong wind would be much
worse even than when still, and if, as must often be the
case with parachutes, they be coiled up, we all know
from our own experience that some of them would be
almost sure to get knotted and tangled together
when, in a sudden emergency, the attempt was made
to pull them all out of their coils in a second or two.
Just picture to yourself what it means : a dozen
coiled cords all close together, themselves all coiled up
in loops, suddenly pulled. Something awkward
appears almost inevitable. And the result of even
one rope going awry may be fatal, for it may prevent
the parachute opening out fully, probably giving it
a " lop-sided " form incapable of gripping the air
effectually and consequently allowing the unfortunate
man to fall with a velocity which means certain
death. This second cause of failure to open, through
entanglement of cordage, has happened in a number
of cases, with fatal results.
So much for the faults of the old primitive para-
chute. Now let us consider for a moment the urgent
need for a parachute which is free from such faults.
The man who goes up in a balloon on a Saturday
afternoon feels so sure of his " craft " that he thinks
he needs no " lifeboat," yet men in ordinary free
balloons have been killed for want of them. The
spectators at country fairs no longer appreciate a
parachute descent as a great and extraordinary
302
THE AERIAL LIFEBOAT
spectacle. But in warfare, with kite balloons by the
dozen, with dirigible balloons by the score and
aeroplanes by the hundred, the call for parachutes
is urgent and irresistible. At all events, Mr. Calthrop
found an irresistible call to devote years of close study,
unceasing toil and considerable sums of money to the
task of perfecting an improved parachute which would
always open and open quickly, and whose cords
would never get entangled. He has the satisfaction
of knowing that by so doing he has provided an
appliance that in the air is as reliable as a lifeboat is
at sea, and that at all times, and from every kind of
aircraft, can be depended upon in case of accident
to save the lives of gallant airmen who but for his
work would be dashed to death. The Great War has
taught us to regard life somewhat cheaply. For
years we were more concerned with taking life than
with saving it, yet surely to save the life of one's own
men is equivalent to taking the lives of one's oppo-
nents, so that even from the point of view of warfare
the saving of life may be a help towards victory.
This is particularly so when the lives saved are those
of the choicest spirits, and among the most highly
trained. It has been reckoned that to make a fully-
trained pilot costs as much as 1500, so that to save
but a few, even in their preparatory flights on the
training-grounds where so many accidents happen,
makes quite an appreciable difference in the cost of
a war, without considering the main question of the
men's lives.
Many inventions arise through a man thinking of
an idea and then seeking and finding some application
303
THE AERIAL LIFEBOAT
for it. Elsewhere in this book, I give examples of
such cases. Here we have an instance of the opposite,
for Mr. Calthrop found his thoughts strongly directed
in this direction by the death of a personal friend,
the Hon. C. S. Rolls, one of the early martyrs in the
cause of aviation, not to mention others who shared
the same risks and in some cases the same fate. His
interest thus aroused, he first studied all the records
which could be found relating to parachute accidents,
so as to ascertain, if possible, what were the causes of
failure. Then he commenced a long series of experi-
ments with a view to removing these causes. Improve-
ment after improvement was tried, unexpected
difficulties were discovered and grappled with, the
kinematograph was called in to record the move-
ments of the falling objects, a task for which it is far
better fitted than the human eye, and after years of
this there emerged the finished parachute, automatic
in its action, perfectly reliable and a true safeguard,
which I am about to describe.
The parachute's body consists of the finest quality
silk carefully cut into gussets of such a shape that
when sewn together somewhat after the manner of
the cover of an umbrella, they form a shallow bag,
parabolic in section, of that particular shape which
the material would assume naturally were it perfectly
elastic when enclosing its resisting body of com-
pressed air. 'W
At intervals round the edge are fastened twenty-
four V-shaped tapes. These are only a few feet long
and the lower end of each V-shaped pair is attached
to a long main tape. There are twelve of these main
304
3
i
o >2
I
1 II
f
I
1!
i
THE AERIAL LIFEBOAT
tapes, and their lower ends unite in a metal disc from
which is suspended the sling and harness by which
the man is supported.
So the twenty-four short tapes form twelve V's to
the points of which are attached the twelve long
tapes which support the man. The reason why tapes
are used in this particular parachute and not cords
will be referred to later.
In the crown of the silk body there is the usual
hole for the purpose of forming the air-rudder to
steady the parachute in its descent.
And now we can consider the first great feature of
this wonderful invention and ask ourselves these
questions : "By what means is it made to open ? "
" What makes it more reliable than others ? "
To answer that we must first see why the others
sometimes refused to open. In whatever way an
ordinary parachute may be packed it must, when
coming into use, assume the state of a shut umbrella
with a hole in the top.
In this condition it is assumed that as it falls the air
will find a way in through the lower end and will blow
the parachute open in precisely the same way that a
strong wind will sometimes blow out the folds of an
umbrella.
But, as a matter of fact, the loose folds of a para-
chute, when the edge of the gussets is gathered in, are
sure to overlap and enfold each other more or less.
Thus, when in the shut-umbrella state, it sometimes
happens that air which is inside can escape upwards
through the hole more easily than fresh air can get in
from below. The parachute, in such a state, is, let us
u 305
THE AERIAL LIFEBOAT
imagine, falling rapidly through the air. The result
is just the same as if it were still and the air were
rushing upwards past it. And the upward rush past
the top hole tends to suck air out through the hole
faster than fresh air can find a way in at the bottom.
This is the principle of the ejector, which engineers
have put to many uses. For example, the vacuum
brakes employed on many large railways owe all
their power to stop a train to a vacuum caused by an
ejector. There is a short tube or nozzle, placed in
the centre of another tube through which steam
blows. The action of the steam in the outer tube
as it rushes past the end of the inner tube drags
after it the air which is in the inner tube so
effectively as to produce quite a good vacuum. And
in precisely the same way, the upward rush of
air past the parachute, or what is just the same,
the falling of the parachute through stationary air,
can suck the air from inside the latter and create a
vacuum in it if the gussets gathered together at the
mouth unfortunately overlap one another and are thus
locked together by the pressure of the air striving to
get in. Thus, instead of the downward fall causing
the ordinary parachute to open, as in most cases it
will do quite well, the fall under these particular
conditions actually binds its folds together and
prevents it from opening. It is true this does not
often happen, but the risk is always present at every
drop, and this unreliability has cost the lives of
brave men and women, and the knowledge of this
constant risk has led others to write down the para-
chute a failure, by reason of its known unreliability
306
THE AERIAL LIFEBOAT
to open instantly. Even when it does open the
depth it falls before it opens is so variable, by reason
of the fight between vacuum and pressure, that it
may be one hundred feet one time and one thousand
feet next time with the same parachute.
Now the " Guardian Angel " is designed so that
those conditions cannot occur. Its silken covering
is first laid out on the ground and into the centre is
introduced a beautifully-designed disc of aluminium,
somewhat like a large inverted saucer, of exceeding
lightness but of ample strength for what it has to do.
Then the silk body is pleated and folded back over
the upper part of this launching-disc and gradually
packed so that it occupies but a very small space upon
the upper surface of the disc. It is so folded that its
edge comes in the topmost layer and also in such a
manner that on the tapes being pulled the silk unfolds
easily and regularly, flowing down as it were over the
edge of the disc almost as water flows if allowed to
fall from a tap upon the centre of an inverted saucer.
After the folding is complete another aliminium disc
is placed above the packed silk body which shields it
from the enormous ah* pressure when it is being
released from an aeroplane flying at top speed. The
upper and lower fabric covers are then superimposed
and sealed and the " Guardian Angel " parachute is
ready for use.
The tapes, likewise, are folded up, in a special way
upon the bottom cover, which is sprung over the
bottom of the disc. The bottom cover with the
tapes upon it, is pulled away by the weight of the
airman as he makes his jump to safety, and the tapes
307
THE AERIAL LIFEBOAT
are so arranged that a pull upon them causes them
to draw out steadily and smoothly, almost like water
falling from a height.
If we regard the silk as forming a shallow bag
inverted, we may say that it is folded upon the disc
inside out and the function of the disc is to cause it
to spread and enclose a wide column of air as it is
pulled from its folds. To commence with it is nothing
more than so much folded-up silk, but from the first
moment of action it becomes a bag with a wide-open
mouth, for its open mouth cannot be smaller than the
disc. Therefore, from the first instant it begins to
grip the air and the ejector action never gets a
chance to commence. The pressure of air inside is
from the very commencement of the fall greater than
that of the surrounding air. Moreover, the disc
covers the hole until the parachute is actually open,
thereby making ejector action doubly impossible.
The widely-opened mouth of the air-bag (I cannot
help repeating that term for it is so expressive)
swallows up more and more air as the thing falls
rapidly, with the result that the air inside is instantly
compressed and the increasing pressure as the silk is
more and more fully drawn out causes it to expand
until the whole is fully extended like a huge umbrella.
The instant compression of the enclosed column of air
is what causes it always to open automatically.
When once it is pointed out it is easy to see what a
difference the presence of this disc makes. It is so
simple that it cannot fail to act and having once
produced that open mouth all the rest is due to the
action of natural forces which can be absolutely
308
THE AERIAL LIFEBOAT
relied upon. The ordinary parachute with its hope-
less irregularities has, in fact, been converted into a
machine whose action can never fail.
The disc is fastened to the balloon or aeroplane and
is left behind when the parachute falls, having done
its work.
And now let us consider the tapes. As has already
been remarked, a series of coiled cords cannot be
relied upon to pull out straight without possibility of
entanglement, but a tape, if folded to and fro like a
Chinese cracker, will invariably do so. So packed
tapes have been substituted for coiled corded rigging,
with the certainty that they cannot be entangled in
the fiercest air current.
And now we come to another interesting feature.
The man is not suspended directly from the small
disc to which the tapes are attached but by a non-
spinning sling which contains a shock absorber.
This latter consists of a number of strands of rubber
and it is owing to its action that the aviator who
trusts his life to the parachute suffers little or no
shock ; even when the instant opening of the para-
chute begins to arrest his fall. And not only does it
save him from shock, but it also avoids the possi-
bility of too great a stress coming suddenly upon the
parachute or its rigging of tapes.
The aviator himself is attached to the parachute
through the shock-absorber sling, by means of a
harness which he wears constantly throughout his
flight, so that in the event of trouble he only has to
jump overboard and the parachute automatically
does the rest. This harness consists of two light but
309
THE AERIAL LIFEBOAT
strong aluminium tubular rings through which he
places his arms, combined with a series of straps
which can be so adjusted that the stress of carrying
him comes upon those parts of his body best adapted
to bear it.
This improved parachute is the only one which is
capable of being used instantly and without prepara-
tion for descent from an aeroplane flying at top
speed. It is easy to see that it is one thing to drop
from a stationary or nearly stationary balloon and
quite another to dive from an aeroplane at one
hundred miles per hour. The latter is equivalent to
suddenly trusting oneself to a parachute during the
strongest gale. It has been found, by experiment,
however, that high speed is no bar to the use of this
parachute since it only causes the parachute to open
a little more quickly than usual, which means that it
can be used with safety from an even lower height.
Under the worst conditions this wonderful para-
chute can be relied upon always to open and carry its
load at a height of only one hundred feet, and its
use is safe in all circumstances when dropped from
two hundred feet above the ground. After it has
once got into operation and taken charge of affairs,
so to speak, the man descends at the rate of only
fifteen feet per second, which is just about the same
as dropping from a height of a little over three feet.
In other words, he will arrive on the ground with no
worse bump than you would get by jumping off the
dining-room table.
But suppose that there were a wind blowing :
would not the parachute come down in a slanting
310
THE AERIAL LIFEBOAT
direction and then drag the man along ? Or may he
not alight upon a tree or the roof of a house, only to
be pulled off again and flung headlong ? Quite true
he might, were not proper provision made for such
occurrences. Embodied in the harness is a lock
which can be instantly undone, by a simple move-
ment of a lever in the hand, and by its aid the man on
touching earth or on alighting upon anything solid
can release himself instantly, after which the parachute
can sail away whither it will, but he will be safe and
sound.
What Mr. Calthrop has accomplished by the
invention of his " Guardian Angel " parachute may
be summarised briefly by saying that he has reduced
the minimum height from which a parachute could
be dropped from two thousand to two hundred feet,
and that he has made it possible to launch a para-
chute, with the certainty of safety, from any kind of
aircraft flying at the slowest or highest speed of
which they are capable.
You are only a boy now, but when in years to come
you are quite old and have grey hair you may become
a Member of the Air Board and who knows it may
become your duty to decide that this great invention
shall be always used on the training grounds to save
the lives of the young men, not yet born, who are then
learning to fly. During the War, one was killed every
day, 365 in a year, many of whom might have been
saved had more " Guardian Angels " been in use.
INDEX
Acetone, 36, 57, 58
Acetylene, 58
Aeroplanes, types of, 285, 286
Air-raft equipment, 89
Alcohols, 49, 50, 51, 52, 55,
139
Aluminium, 157
Anchors for floating bridges,
80
Anti-aircraft guns, 119
Aquitania, s.s., 197
Armourer, 17
Austrian heavy mortars, 111,
114, 117
Bamboo, bridges made of,
87
Basic steel, 101
Becquerel, H., 40
Benzene, 35
Bessemer, Sir Henry, 93, 98,
99, 100, 102
Blast-furnace, 94, 95
Boilers in warships, 176
Breech-block of guns, 131,
132
" Brennan " torpedo, 219
Calthrop, E. R., 300, 311
Canet, Gustave, 129
Canvas boats, 86
Carbolic acid, 35
Carbon, 28, 50, 94, 98
Carbon in steel, 106
Carbon monoxide, 95
Carriages of guns, 116
Cast iron, 96, 97
Catamaran bridge, 90, 91
Caustic soda, 22, 23, 24
Chloride of lime, 23
Chlorine, 18, 19, 21, 23, 52
Chloroform, 59
Clerk-Maxwell, Professor J.
243
Coal dust explodes, 29
Coal tar, 34
Contact-firing mines, 65
Copper, 147
Cordite, 36
Cotton explosives, 32, 33
Countermining, 63, 73
Crucible steel, 104
Curie, Madame, 41
Detonator, 37
Diastase, 55
Diesel engine, 178, 236
Dreadnought, H.M.S., 194
INDEX
Driving-band on shells, 142
Dynamite, 31
Electricity, positive and nega-
tive, 20, 21
Electrodes, 19
Electrolysis of salt, 18, 19
Electrolyte, 19
Electrons, 42
Electroscope, 43
" Elia " mines, 70
Ethane, 51
Ether, 58, 59
Explosion, force of, 30
Field guns, 108, 114
Flotilla leaders, 189
Fractional distillation, 35, 57
French field artillery, 108
Froude, William, 203
Fulminate of mercury, 37
Glycerine, 25
Gravity, action of upon shells,
122, 123, 124
" Guardian Angel " para-
chute, 300
Gun-cotton, 32, 33
Gunpowder, 27, 30
Gyroscope, uses of, 216, 234
Helium, 42
Hertzian waves, 243
High explosives, 36, 138
High-explosive shells, 137
High-speed steel, 105
Hop-pole bridges, 88
Horse artillery, 108, 114
Howitzers, 111, 114, 115
Hydrostatic valve, 68, 217
Hydroxyl, 52, 53
"Interference" of waves, 241,
248
Invincible, H.M.S., 196
lonogens, 20
Ions of common salt, 19
Iron ore, 93
Kieselguhr, 32
Ladysmith, guns at, 109
Launching a ship, 211
" Limit " gauges, 140
Line-of-battle ships, 191
Lion, H.M.S., 197
Lyddite, 35
Machine guns, 115
Magnetic detector, 257
Malt, 55
Marconi, 248
Methane, 51
Methylated spirit, 54
Mine, submarine, 63 et seq.
Mine, subterranean, 61
Mortars, 111, 112, 113, 114,
118
Naval guns, 112, 120 et seq.
Naval shells, 136, 137
Nitrate of potassium, 30
3M
INDEX
Nitro-benzene, 35
Nitroglycerine, 26, 31, 32
Nitrogen, action of, 26, 30
Observation mines, 65
Oil fuel, 177
Olympic, s.s., 197
Organic substances, 26
Orion, H.M.S., 193
Parachutes, 297
Paraffins, 51
Periscope, 225, 233
Petrol engine, 181, 182
Phenol, 35
Picric acid, 35
Pig iron, 95, 97
Poison gas, 23
Pontoons for bridging, 77
Propellants, 36, 125, 138
Radio-activity, 41
Radium, 39 et seq.
Rays from radium, 41, 42
Reeds, bridges made of,
85
Repulse, H.M.S., 192
Rheumatism and radium, 47
Rifling in guns, 143
Rolling mills, 98, 139
Salt and explosives, 18
Saltpetre, 27, 29, 30
Scott, Sir Percy, 109
Sea-planes, 287
Shell-steel, 146
Shrapnel shells, 137, 144,
145
Siemens steel, 102, 103
Sights for guns, 133
Smokeless powder, 31
Soap, 25
Sodium, 18, 22
Soluble seal used in mines,
72
Spinning action of shells,
142
Stability of aeroplanes, 293
Steam-engines, 170
Steel for guns, 126
Sulphuric acid, 31, 32, 150
Suspension bridges, 83
" Tanks," 276
Telephone used in telegraphy,
266
Tin, 152, 153
T.N.T., 35
Toluene, 35
Torpedo boats, 184
Trajectory, 122
Trench mortars, 118
Trestle bridges, 80, 83
Tri-nitro-benzene, 35
Tri-nitro-phenol, 35
Tri-nitro-toluene, 35
Tungsten, 105, 153
" Tuning " wireless telegraph
apparatus, 255
Turbine, steam, 17
Uranium, 41
315
INDEX
" Whitehead " torpedo, 215
Wire- wound guns, 128
Wolfram, 153
Wood spirit, 57
Wrought iron, 97
Wyoming, U.S. battleship, 195
X-rays, 42, 43
Zeppelin v. aeroplane, 46
Zinc, 149, 150, 151
PRINTED BT WILLIAM BRENDON AND SON, LTD., PLYMOUTH, ENGLAND. 1917
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DESCRIBING THE WONDERFUL INTELLIGENCE OF ANIMALS REVEALED IN
THEIR WORK AS MASONS, PAPER MAKERS, RAFT dr" DIVING-BELL BUILDERS,
MINERS, TAILORS, ENGINEERS OF ROADS & BRIDGES, &O. <5rC.
BY H. COUPIN, D.Sc., & JOHN LEA, B.A.(CANTAB.)
With Thirty Illustration!. Extra Crown 8w., 5s.
" Will carry most readers, young and old, from one surprise to another."
Glasgow Herald.
" \ charming subject, well set forth, and dramatically illustrated."
Athenaum.
" It seems like pure romance to read of the curious ways of Nature's crafts-
men, but it is quite a true tale that is set forth in this plentifully illustrated
book." Evening Citizen.
THE ROMANCE OF INSECT LIFE
DESCRIBING THE CURIOUS <&- INTERESTING IN THE INSECT WORLD
BY EDMUND SELOUS
Author of " The Romance of the Animal World," &.
With Sixteen Illustration. Extra Crown 8vo, 5s.
14 An entertaining volume, one more of a series which seeks with much
success to describe the wonders of nature and science in simple, attractive
form." Graphic.
" Offers most interesting descriptions of the strange and curious inhabi-
tants of the insect world, sure to excite inquiry and to foster observation.
There are ants white and yellow, locusts and cicadas, bees and butterflies,
spiders and beetles, scorpions and cockroaches and especially ants with
a really scientific investigation of their wonderful habits not in dry detail, but
in free and charming exposition and narrative. An admirable book to put in
the hands of a boy or girl with a turn for natural science and whether or
not." ducati<mal Times.
THE ROMANCE OF THE ANIMAL
WORLD
DESCRIBING THK CURIOUS AND INTERESTING IN NATURAL BISTORT
BY EDMUND SELOUS
With Sixteen full-page Illustrations. Extra Crown 8vo, 5$.
" Mr. Selous takes a wide range in Nature ; he has seen many wonders
which he relates. Open the book where we will we find something astonish-
ing." Spectator.
" It is in truth a most fascinating book, aa full of incidents and as various
in interest as any other work of imagination, and, beyond the pleasure in the
reading there is tne satisfaction of knowing that one is in the hands of a
genuine authority on seme of the most picturesque subjects that natural
history affords. Mr. Selous' method is strong, safe, and sound. The volume
has numerous illustrations of a high order of workmanship and a handsome
binding of striking design." School Government Chronicle.
SEELEY, SERVICE CO. LIMITED
THE ROMANCE OF
MODERN ELECTRICITY
DESCRIBING IN NON-TECHNICAL LANGUAGE WHAT IS KNOWN ABOUT
ELECTRICITY &> MANY OF ITS INTERESTING APPLICATIONS
BY CHARLES R. GIBSON, A.I.E.E.
AUTHOR OF "ELECTRICITY or TO-DAY," KTC.
Extra Croion 8vo. With 34 Illustrations and 11 Diagrams. 5s.
" Everywhere Mr. Charles R. Gibson makes admirable use of simple analogies
which bespeak the practised lecturer, and bring the matter home without technical
detail. The attention is further sustained by a series of surprises. The description
of electric units, the volt, the ohm, and especially the ampere, is better than we nave
found in more pretentious works." Academy.
"Mr. Gibson's style is very unlike the ordinary text-book. It is fresh, and is
non-technical. Its facts are strictly scientific, however, and thoroughly up to date.
If we wish to gain a thorough knowledge of electricity pleasantly and without too
much trouble on our own part, we will read Mr. Gibson's ' romance.' "
Expository Timet.
"A book which the merest tyro totally unacquainted with elementary electrical
principles can understand, and should therefore especially appeal to the lay reader.
Especial interest attaches to the chapter on wireless telegraphy, a subject which ia
apt to ' floor' the uninitiated. The author reduci-s the subject to its simplest aspect,
and describes the fundamental principles underlying the action of the coherer in
language so simple that anyone can grasp them." Electricity.
THE ROMANCE OF THE SHIP
THE STORY OF HER ORIGIN AND EVOLUTION FROM THE
EARLIEST TIMES
BY E. KEBLE CHATTERTON, B.A. OXON.
AUTHOR OF "SAILING SHIPS AND THEIR STORY," KTC. ETC.
With 34 Illustrations. Price 5s.
"One of the most instructive and intelligent treatises on sea-life that ft has yet
been our lot to peruse." Syren and Shipping.
"There is not a doubt about this volume being the best of its kind yet pub-
lished." Dundee Courier.
"Absorbingly Interesting and highly instructive." Liverpool Daily Pott.
THE ROMANCE OF MODERN
ASTRONOMY
BY HECTOR MACPHERSON, JUNIOR
With 32 Illustrations & Diagram*. Extra Crown Svo. Price 5s.
" We can conceive no book better adapted than this handsomely got up and
beautifully illustrated volume to attract the young, and even older people to the
study of the sublimest of sciences. 11 Edinburgh Newt.
"Described in popular language, yet with a thoroughness which will give the
reader a surprisingly complete grasp of the subject." Chrutian.
"An ideal book for presentation, as indeed all Messrs. Seeley's Romance books
are." Eastern Morning News.
" An excellent compendium of the most interesting facts in astronomy, told in
popular language. Great care has evidently bean taken to secure accuracy. The
illustrations are exceedingly good." The Athenteum.
SEELEY, SERVICE 6- CO. LIMITED
Stories by Prof. A. J. Church
"The Headmaster of Eton (Dr. the Hon. E. Lyttelton) advised
his hearers, in a recent speech at the Royal Albert Institute, to read
Professor A. J. Church's "Stories from Homer," some of which, he
said, he had read to Eton boys after a hard school day, and at an age
when they were not in the least desirous of learning, but were anxious
to go to tea. The stories were so brilliantly told, however, that those
young Etonians were entranced by them, and they actually begged of
him to go on, being quite prepared to sacrifice their tea time."
Profusely illustrated. Extra Crown Svo, 5*. tach
The Children's /Eneid
The Children's Iliad
The Children's Odyssey
The Faery Queen and her Knight
The Crusaders
Greek Story and Song
Stories from Homer
Stories from Virgil
The Crown of Pine
Stories from Greek Tragedians
Stories of the East from Herodotus
Story of the Persian War
Stories from Livy
Roman Life in the Days of Cicero
With the King at Oxford
Count of Saxon Shore
The Hammer
Story of the Iliad
Story of the Odyssey
Stories from Greek Comedians
Heroes of Chivalry a'ad Romance
Helmet and Spear
Stories of Charlemagne
Extra Crffwn &w, illustrated, and tther tites
Last Days of Jerusalem
The Burning of Rome
The Fall of Athens
Stories from English History
Patriot &* Hero
2s.6d.
The Chantry Priest of Barnet
Heroes of Eastern Romance
Three Greek Children
To the Lions
A Young Macedonian
Heroes of Eastern Romance
is. 6d.
Heroes and Kings
Greek Gulliver
Nicias
Story of the Iliad and ^Eneid
To the Lions
is.
Story of the Iliad
Story of the Odyssey
Story of the Iliad and ^neid
&,
Last Days of Jerusalem
Story of the Iliad
Story of the Odyssey
Storiei from Virgil
SEELEY, SERVICE fc 1 CO. LIMITED
A Catalogue of Books for Young
People, Published by %
Seeley, Service &P Co Limited,
38 Great Russell Street, London
Some of the Contents
Adventure, The Library of . . . .12
Bedford Library, The . . . . 2
Church, Stories by Professor .... 3
Giberne, Books by Miss ..... 6
Heroes of the World Library, The ... 8
Marshall, Stories by Miss Beatrice ... 9
Marshall, Stories by Mrs. ..... 9
Missionary Biographies . . . . . .10
Olive Library, The . . . . . .10
Pink Library, The . . . . . .11
Prince's Library, The . . . . . .11
Romance, The Library of . . . . -13
Royal Library, The . . . . . .12
Russell Series, The . . . . . .12
Scarlet Library, The 14
Science for Children . . . . . .14
Sunday Echoes ....... 2
Wonder Library, The . . . . . .16
The Publishers will be pleased to send post free their complete
Catalogue or their Illustrated Miniature Catalogue
on receipt of a post-card
CATALOGUE OF BOOKS
Arranged alphabetically under the names of
Authors and Series
AGUILAR, GRACE.
The Days of Bruce. With Illustrations. Extra crown
Sro, is. (SCARLET LIBRARY.)
ANDERSEN, HANS.
Fairy Tales. With Illustrations, is. 6d., 2s., and 38. 6d.
(SCARLET and PRINCE'S LIBRARIES.)
ALCOTT, L. M.
Little Women and Good Wives. With Illustrations. .
(ScARLrr LIBRARY.) Alo Little Women, Extra crown 8ro, is. 6d. ; and
Good Wives, Extra crown 8o, i. 6d.
Arabian Nights' Entertainments. With Illustration*, is. 6d.
( PINK LIBRARY); *.( ROYAL & ScARijrr LIMAEIM) ; 31. 6d. (PRLNCZ'S LIBRARY).
BALLANTYNE, R. M.
The Dog Crusoe and His Master. With Illustrations
by H. M. BROCK, R.I. Extra crown 8vo, as. and is. 6d.
BEDFORD LIBRARY FOR BOYS AND GIRLS, THE.
A Series of books describing the Adventure*, Bravery, and Resource of
Soldiers, Sailors, and others in all Parts of the World. Sq. Crown 8 TO,
with many Illustrations in Colour, 3*. 6d.
Daring Deeds of Famous Pirates. By Lieut. E. KEBLI
CHATTXRTON, R.N.V.R., Author of" Sailing Ships and their Story," 5tc. Ac.
Daring Deeds of Hunters and Trappers. By ERMEST
YOUNG, B.Sc., F.R.G.S., Author of " The King of the Yellow Robe, " &c. Ac
BERTH ET, E.
The Wild Man of the Woods. With Illustration*, is. 6d.
BLAKE, M. M.
The Siege of Norwich Castle. With Illustrations, 58.
BOISRAGON, Major ALAN M. Late Royal Irish Fusiliers.
Jack Scarlett, Sandhurst Cadet. With Coloured Illustrations.
Extra crown STO, 51.
BROCK, Mrs. CAREY.
Dame Wynton's Home. A Story Illustratiye of the Lord's
Prayer. With Eight Illustrations. Crowm STO, is. 6d.
My Father's Hand, and other Stories. Crown 8vo, 2s.
Sunday Echoes in Weekday Hours. A Series of Illustra-
tive Tales. Seen Vols. Crown 8vo, 3*. 6d. each.
I. The Collects.
II. The Church Catechism.
III. Journeyings of the Israelites.
IV. Scripture Characters.
Working and Waiting. Crown 8ro, 5*.
V. The Epistles and Gospels.
VI. The Parables.
VII. The Miracles.
Seeley, Service & Co Limited
BROWN LINNET.
The Kidnapping Of Ettie, and other Tales. With Sixteen
Illustration*. Crown STO, 51.
BUNYAN, JpHN.
The Pilgrim's Progress. With Illustrations. Extra crown
STO, as. (SCARLET LIBRARY).
CARTER, Miss J. R. M.
Diana Polwarth, Royalist. A Story of the Life of a Girl
in Commonwealth Day. With Eight Illustrations. Crown STO, 3*. 6d.
CHARLESWORTH, Miss.
England's Yeomen. Crown 8ro, is. 6d.
Oliver Of the Mill. With Eight Illustrations. Cr. STO, as. 6d.
Ministering Children. i. Olive Library. Crow STO, cloth gilt,
as. 6d. l. Scarltt Library. Crown SVG, cloth, is. 3. With 4 Illustra-
tions. Cloth, is. 6d.
Ministering Children: A Sequel. With Illustrations.
Cloth, is. 6d. All* with Eif ht Illuitratioai. Cloth, 21. and at. 6d.
The Broken Looking-Glass. Crowa STO, is.
The Old Looking-Glass and the Broken Looking-
GlASS ; or, Mri. Dorothy Cope'i Recollections of Service. In one Tolume.
With Eif ht Illustration*. Crewn 8vo, is. 6d.
CHATTERTON, E. KEBLE.
The Romance of the Ship. With 33 Illus. Ex. cr. 8ro, 51.
The Romance of Piracy. Many Illu. Ex. cr. STO, 51.
CHURCH, Professor ALFRED J.
"Toe Headmaster of Eton (Dr. the Hon. B. Lyttelton) advised his kearers, in a
recent speech at the Royal Albart Institute, to read Professor A. J. Church's
' Storie* from Homer,' some of whick, ha said, ke had read to Eton boys after a
kard school day, and at an aye who* they were not in the least desirous of learn-
ing;, but were aaxicns to go to tea. The stcriea were so brilliantly told, however,
that those young Etonians were entranced by them, and they actually begged of
him to ro on, beinj quit* prepared to sacrifice their tea time/
The Children's >Eneid. Told for Little Children With
TwelTe Illustrations in Colour. Extra crown STO, 51.
The Children's Iliad. Told for Little Childre.. With
Twelve Illustrations in Colour. Extra crown STO, 5s.
The Children's Odyssey. Told for Little Children. With
Twelve Illustrations in Colour. Extra crown STO, 5*.
The Crown Of Pine. A Story of Corinth and the Isthmian
Games. With Illustration in Colour by GEORGE MORROW. Ex. cr. STO, 51.
The Count Of the Saxon Shore. A Tale of the Departure
of the Romans from Britain. With Sixteen Illustrations. Crown STO, 51.
The Faery Queen and her Knights. Stories from Spenser.
With Eight Illustrations in Colour. Extra crown STO, 51.
Stories of Charlemagne and the Twelve Peers of
France. With Eight Illustrations in Colour. Crown 8vo, 51.
The Crusaders. A Story of the War for the Holy Sepulchre.
With Eight Illustration! in Colour. Extra crown STO, 51.
Stories from the Greek Tragedians. With Illustrations.
Crown STO, 51.
I
Seeley, Service & Co Limited
CHURCH, Prof. ALFRED J. Continued.
Greek Story. With 16 Illustrations in Colour. Cm. STO, 51.
Stories from the Greek Comedians. With Illustrations.
Crown STO, 51,
The Hammer. A Story of Maccabean Times. With Illus-
trations. Crown 8vo, 51.
The Story of the Persian War, from Herodotus. With
Coloured Illustrations. Crown STO, 5*.
Heroes 'of Chivalry and Romance. With Illustrations.
Crown Svo, 5$.
Stories Of the East) from Herodotus. Coloured Illustrations.
Crown 8vo, 51.
Helmet and Spear. Stories from the Wars of the Greeks and
Romans. With Eight Illustration! by G. MORROW. Crown 8vo, 51.
The Story Of the Iliad. With Coloured Illustrations. Crown
STO, 5. Also Thin Paper Edition, cloth, is. nett; leather, 3$. nett.
Cheap Edition, 6d. nett ; also cloth, is.
Roman Life in the Days of Cicero. With Illustrations.
Crown STO, 5$.
Stories from Homer. Coloured Illustrations. Crn. 8vo, 59.
Stories from Livy. Coloured Illustrations. Crn. 8vo, 58.
Story Of the Odyssey. With Coloured Illustrations. 58.
Also Thin Paper Edition, cloth, is. nett ; leather, js. nett. Cheap Edition,
6d. nett. Also cloth, i*.
Stories from Virgil. With Coloured Illustrations. Crown
8ro, 5. Cheap edition, sewed, 6d. nett.
With the King at Oxford. A Story of the Great Rebellion.
With Coloured Illustration*. Crown STO, 58
Crown 8vo, 3/6 each.
The Fall Of Athens. With Illustrations. Crown 8ro, 38. 6d.
The Burning of Rome. A Story of Nero's Days. With
Sixteen Illustrations. Cheaper Edition. Crown STO, js. 6d.
The Last Days of Jerusalem, from Josephus. Crown 8vo,
3*. 6d. Also a Cheap Edition. Sewed, 6d.
Stories from English History. With many Illustrations.
Cheaper Edition. ReTised. Crown STO, 38. 6d.
Patriot and Hero. With Illustration. Crown 8vo, 33. 6d.
Extra crown 8vo, 2/6 each.
To the Lions. A Tale of the Early Christians. With
Coloured Frontispiece and other Illustrations, is. 6d.
Heroes of Eastern Romance. With Coloured Frontis-
piece and Eight other Illustrations. Extra crown Svo, zs (ROTAJL LIBRARY);
as. 6d.
A Young Macedonian in the Army of Alexander the
Great. With Illustrations. Extra crown STO, si. 6d,
The Chantry Priest. With Illustrations, as. 6d.
Three Greek Children. Extra crown 8vo, is. 6d.
4
Seeley, Service & Co Limited
CHURCH, Prof. ALFRED ]. Continued.
Crown 8vo, 1/6 each.
A Greek Gulliver. Illustrated. Crown 8 TO, is. 6d.
Heroes and KingB. Stories from the Greek. Illus. n. 6d.
The Stories of the Iliad and the ^Eneid. With Illustra-
tions. i6mo, sewed, is. ; cloth, n. 6d. Also without Illustrations, cloth, is.
To the Lions. A Tale of the Early Ckristians. With Illus-
CODY, Rev. H. A. tntion*. Crown ITO, xs. M.
On Trail and Rapid. By Dog-lied and Canoe. A Story of
Bishop Bompas's Life among the Red Indians and Esquimo. Told for Boys
and Girls. With Twenty-six Illustrations. Extra crown Sro, is. 6d.
Apostle Of the North, An. Memoirs of Bishop Bompas.
With 41 Illustrations and a Map. 7*. 6d. nett. New and Chtafir R&tiui.
With Illustrations. 4^ Extra crown Sro, 55. nett. (CROWN LIBRARY.)
COOLIDGE, SUSAN.
What Katy did at Home and at School. Illustrations
in Colour by H. M. BROCK, R.I. Crown 8vo, *s. (SCAXLIT LIBRARY.)
What Katy did at Home. Extra crown 8vo, is. 6d.
COUPIN, H., D.Sc., and J. LEA, M.A.
The Romance of Animal Arts and Crafts. With
Twenty-five Illustrations. Extra crown 8vo, <s.
COWPER, F.
Caedwalla : or, The Saxons in the Isle of Wight. With Illustra-
tions. Extra crown Svo, 33. 6d. (PRINCE'S LIBRARY.)
The Island Of the English. A Story of Napoleon's Days.
With Illustrations by GEORGE MORROW. Crown 8 vo, 2s. 6d.
The Captain Of the Wight. With Illustrations. Extra
CRAIK, Mrs. crown 8vo, 3 s. 6d.
John Halifax. Illustrated. Extra cr. Svo, 2s. (SCARLET LIBY.)
CURREY, Commander E. HAMILTON, R.N.
Ian Hardy, Naval Cadet Coloured Illus. Ex. cr. 8vo, 5*.
Ian Hardy, Midshipman. A stirring story for boys. With
Coloured Illustrations. Extra crown Svo, 55.
Ian Hardy, Senior Midshipman. With Col. Illus., 5s.
DAVIDSpN, N. J., B.A.
A Knight-Errant and his Doughty Deeds. The Story
of Amadis of Gaul. Cel. Illus. by H. M. BROCK, R.I. Crown JYO, p.
The Romance of the Spanish Main. Ex. crown STO.
With many Illustrations, 515.
Things Seen in Oxford. Cloth, as. nett; leather, js. nett
DAWSON, Rev. Canon E. C. and *' Bett -
Heroines of Missionary Adventure. With Twenty-four
Illustrations. Extra crown SYO, 51.
Lion-Hearted. Bishop Hanuington's Life Retold for Boys
and Girls. Illustrated. Crown |Y, as., *s. id. (Oun LMARY), and is. 6d.
In the Days of the Dragons. Crown STO, is. 6d.
Missionary Heroines in Many Lands. Ex. cr. 8ro, is. 6d.
Missionary Heroines of the Cross. With Illus., 2s. 6d.
5
Secley, Service & Co Limited
DEFOE, DANIEL.
Robinson Crusoe. With Illustration* Extra crcwn STO,
1*. and 3*. 6d. (SCARLET AND PRINCE'S LIBRAHZ*.)
ELLIOTT, Miss.
Copsley Annals Preserved in Proverbs. With Illustra-
tioni. Crown STO, 31. 6d.
Mrs. Blackett. Her Story. Fcap. STO, is.
ELLIOT, Prof. G. F. SCOTT, M.A., B.SC., F.R.G.S., F.L.S.
The Romance Of Plant Life. Describing the curioui and
interesting in tht Plant World. With 34 Illustration*. Ex. crown STO, 51.
"Popularly written by a Bum of (r**t scientific accomplishments."
TUB OUTLOOK.
The Romance of Savage Life. With Forty-ire Illustra-
tioni. Extra crown Xvo, 51.
The Romance of Early British Life : From the Earliest
Times to the Coming of tht Daaes. With 30 Illustration*. Ex. crown STO, 5*.
EVERETT-GREEN, EVELYN.
A Pair Of Originals. With Coloured Frontiipiece and Eight
other Illustrations. Extra crown STO, si. & is. 6d*
FIELD, Rev. CLAUD, M.A.
Heroes of Missionary Enterprise. With many Illustration*
Extra crown STO, 51.
Missionary Crusaders. With many Illustrations and a Frontis-
piece in Colour, it. 6d.
GARDINER, LINDA.
Sylvia in Flowerland. With 16 Illustration. Cr. 8ro, 31. 6d.
GAVE, SELINA.
Coming; or, The Golden Year. A Tale. Third Edition.
With Eight Illustrations. Crown STO, 51.
The Great World's Farm. Some Account of Nature's
Crops and How they are Grown. With a Preface by Professor BOULOU,
and Sixteen Illustrations. Second Edition. Crown STO, 51.
GIBERNE, AGNES.
The Romance of the Mighty Deep. With Illustration!. 5*.
"Most fascinating:." DAILY NEWS.
Among the Stars I or, Wonderful Things in the Sky. With
Coloured Illustration*. Eighth Thousand. Crown STO, 51.
Duties and Duties. Crown STO, 5s.
The Curate's Home. Crown STO, 2*. 6d.
The Ocean of Air. Meteorology for Beginners. Illustrated.
Crown STO, 5*.
The Starry Skies. First Lessons on Astronomy. With
Illustrations. Crown STO, is. 6d.
Sun, Moon, and Stars. Astronomy for Beginners. With a
Preface by Profeor PUTCHAXD. With Coloured Illustrations. Twenty-
sixth Thousand. ReTised and Enlarged. Crown STO, 5*.
The World's Foundations. Geology for Beginners. With
Illustrations. Crown STO, 51.
Beside the Waters of Comfort Crown STO, 38. 6d.
f
Seeley, Service & Co Limited
GIBSON, CHARLES R., F.R.S.E.
Our Good Slave Electricity. With many Illustrations.
Extra crown 8 TO, 3*. 6d.
The Great Ball on which we Live. With Coloured
Frontiipiece and many other Illustration!. Extra crown 8vo, 3*. 6d.
The Stars and their Mysteries. With a Coloured Frontis-
piece and 19 Illustrations. Extra crown 8 TO, js. 6d.
Romance of Scientific Discovery. Illustrated. 5.
Heroes of the Scientific World. An Account of the Lives
and Achievements of Scientists of all age*. With 16 Illustrations. 58.
Autobiography of an Electron. Long STO. 3*. 6d. nett.
The Wonders of Electricity. With Eight Illustrations.
Extra crown Sro, it.
The Wonders of Modern Manufacture. Illustrated. a.
Wireless Telegraphy. Many Illustrations, is. nett.
The Romance of Modern Electricity. Describing m
non-technical language what it known about electricity and many of itt
interesting applicationt. With Forty-one Illustrations. Ex. crown 8vo, 51.
" Admirable . . . clear, concise," THK GRAPHIC,
The Romance of Modern Photography. The Discoyery
and its Application. With many Illustrations. Extra crown 8ro, 51.
The Romance of Modern Manufacture. With Twenty-
four Illustrations and Sixteen Diagrams. Extra crown 8ro, 51.
How Telegraphs and Telephones Work. Explained in
non-technical language. With many Diagrams. Crown SYO, it. 6d. nett.
GILLIAT, EDWARD, M.A. Formerly Master at HarrowSchool.
Forest Outlaws. With Illustrations. Crown STO, 51.
Heroes of Modern Crusades. 24 Illus. Ex. cr. SYO, 51.
In Lincoln Green. Illustrated. Crown 8vo, 58.
The King's Reeve. Illustrated by SYDNEY HALL. 38. 6d.
Wolfs Head. With Eight Illustrations. Crown 8vo, 38. 6d.
The Romance of Modern Sieges. 16 Illus. Ex. cr. 8vo, 58.
Heroes of the Elizabethan Age. 16 Illus, Ex. cr. STO, 51.
Heroes of Modern Africa. 16 Illus. Ex. cr. STO, 58.
Heroes Of Modern India. With many Illustrations. Extra
crown 8vo, 51.
Heroes of the Indian Mutiny. With many Illustrations.
Extra crown 8vo, 51.
Stories of Elizabethan Heroes. With Coloured and other
Illustration!. Extra crown 8vo, zs. 6d.
Stories of Great Sieges. With Illus. Ex. cr. STO, as. 6d.
Stories of Indian Heroes. With Illus. Ex. cr. 8To, as. 6d.
GOLDEN RECITER, THE. S RICITKS, Tin GOLDEM.
GREW, EDWIN, M.A. (Oxon.).
The Romance of Modern Geology. A popular account in
non-technical language. With Twenty-four Illustrations. Ex. crown STO, 51,
GRIMM'S FAIRY TALES. With Illustrations. Extra cr. STO,
It. and jt. 6d. (ScAUJtr AMD PHIUCE'S LIBRAJUIS) ; alto Punt LUULAKT, is. 6d.
7
Seeley, Service ft? Co Limited
HEROES OF THE WORLD LIBRARY
Each Volume lavishly Illuitrated. Extra crown 8ro, 51.
Heroes of the Indian Mutiny. By the Rev. EDWARD GILLIAT.
Heroes of the Scientific World. By C. R. GIBSON, F.R.S.E.
Heroes of Modern Africa. By Rev. EDWARD GILLIAT.
Heroes of Missionary Enterprise. By Rev. CLAUD
FIELD, M.A.
Heroes of Pioneering. By Rev. EDGAR SANDERSON, M.A.
Heroines of Missionary Adventure. By Rev. CANOM
DAWSON, M.A.
Heroes of Modern Crusades. By Rev. EDWARD GILLIAT.
Heroes of Modern India. By Rev. E. GILLIAT.
Heroes of the Elizabethan Age. By Rev. E. GILLIAT.
HUGHES, THOMAS.
Tom Brown's Schooldays. With Illustrations. Extra
crown 8vo, 2*. and zs. 6d. (SCARLET AND OLIVE LIBRARIES.)
HYRST, H. W. G. Extra crown 8vo, price 5*.
Adventures in the Great Deserts. With 16 Illustrations.
Adventures in the Great Forests. With 16 Illustrations.
Adventures among Wild Beasts. With 24 Illustrations.
Adventures in the Arctic Regions. With 16 Illustrations.
Adventures among Red Indians. With 16 Illustrations.
Stories of Red Indian Adventure. With Coloured and
other Illustrations. Extra crown STO, 2s. 6d.
Stories of Polar Adventure. Extra crown 8vo, 29. 6d.
KINGSLEY, CHARLES.
Westward Ho ! With Illustrations. Extra crown 8vo, 2s. &
25. 6d. (SCARLET AND OLIVE LIBRARIES.)
KNIGHT-ERRANT AND HIS DOUGHTY DEEDS.
The itory of Amadis of Gaul. Edited by N. J. DAVIDSON, B.A. With
Eight Coloured Illustrations by H. M. BROCK, R.I. Sq. ex. crown STO, 51.
LAMB, CHARLES and MARY.
Tales from Shakespeare. With Illustrations. Ex. crown
STO, 2s. (SCARLET LIBRARY.)
LAMBERT, Rev. JOHN, M.A., D.D.
The Romance of Missionary Heroism. True Stories of
the Intrepid Bravery and Stirring Adventures of Missionaries in all Parts
of the World. With Thirty-nine Illustrations. Extra crown STO, .
Missionary Heroes in Asia. Illustrated. Cr. 8vo, is. 6d.
Missionary Heroes in Africa. Illustrated. Cr. STO, is. 6d.
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E
