[Illustration:
Copyright, Ewing Galloway]
_The drop forge. A fourteen-ton hydraulic press is employed in forging
an immense open hearth steel plate._
POPULAR SCIENCE LIBRARY
EDITOR-IN-CHIEF
GARRETT P. SERVISS
AUTHORS
WILLIAM J. MILLER HIPPOLYTE GRUENER A. RUSSELL BOND
D. W. HERING LOOMIS HAVEMEYER ERNEST G. MARTIN
ARTHUR SELWYN-BROWN ROBERT CHENAULT GIVLER
ERNEST INGERSOLL WILFRED MASON BARTON
WILLIAM B. SCOTT ERNEST J. STREUBEL
NORMAN TAYLOR DAVID TODD
CHARLES FITZHUGH TALMAN
ROBIN BEACH
ARRANGED IN SIXTEEN VOLUMES
WITH A HISTORY OF SCIENCE, GLOSSARIES
AND A GENERAL INDEX
_ILLUSTRATED_
[Illustration: LOGO]
VOLUME FIVE
P. F. COLLIER & SON COMPANY
NEW YORK
Copyright 1922
BY P. F. COLLIER & SON COMPANY
MANUFACTURED IN U. S. A.
MECHANICS
THE SCIENCE OF MACHINERY
BY
A. RUSSELL BOND
FORMERLY MANAGING EDITOR, SCIENTIFIC AMERICAN
[Illustration]
P. F. COLLIER & SON COMPANY
NEW YORK
PREFACE
ALTHOUGH strictly speaking the term “Mechanics” applies to that branch
of Physics that deals with the actions of forces on material bodies,
originally the word had a broader meaning embracing all machinery
and mechanical inventions. To-day popular usage is restoring to the
term its original broad interpretation, and it is in this popular but
rather unorthodox sense that “Mechanics” has been chosen as the title
of this book; for although certain elementary principles of mechanics
are described and explained, the major portion of the book deals with
machines and their evolution to their present stage of perfection.
Machines are man’s creation, and yet in a sense the man of to-day is a
machine product; for modern civilization owes its material and in large
measure its esthetic development to machinery. The story of machinery,
from primitive man’s first attempts to augment his physical powers with
mechanical aids down to the present era of gigantic, steel-muscled
machinery and marvelously intricate mechanisms, is the story of human
progress. It is this story that we have endeavored to tell in the
following pages, but the subject is too large to be covered in a single
volume or even a dozen volumes. Under the circumstances we have been
obliged to confine ourselves to a mere outline, selecting certain
avenues of progress more marked than others and presenting brief sketch
maps of them. We have aimed in this way to give a bird’s-eye view of
the whole story of human progress in things material.
The book has not been written for the mechanical engineer, but for the
layman who would learn of the mechanical contrivances that contribute
to his material welfare; hence technical terms have been avoided, as
far as possible, and where unavoidable have been explained and defined.
A. RUSSELL BOND
CONTENTS
CHAPTER PAGE
I. TOOL-MAKING ANIMALS 9
II. THE ANATOMY OF A MACHINE 20
III. MACHINES FOR MAKING MACHINES 42
IV. COUNTING SECONDS 57
V. PUTTING RIVERS TO WORK 75
VI. LIQUID LEVERS AND GEARS 94
VII. AIR _vs._ WATER 109
VIII. AIR SPRINGS AND CUSHIONS 126
IX. POWER FROM HEAT 139
X. BURNING FUEL IN THE ENGINE CYLINDER 155
XI. WHEN COAL AND OIL ARE EXHAUSTED 171
XII. INVASION OF THE SEA 182
XIII. SLIDING, ROLLING, WALKING, AND CREEPING 203
XIV. INVASION OF THE SKY 219
XV. HELPING THE FARMER 239
XVI. MACHINING THE EARTH 251
XVII. FROM FIBER TO FABRIC 268
XVIII. THE MAKING OF PAPER 289
XIX. TYPESETTING AND PRINTING MACHINERY 300
XX. CAST IRON, WROUGHT IRON, AND STEEL 314
XXI. ANIMATED MACHINERY 326
XXII. HEAT VACUUMS 345
XXIII. ENGINES OF DESTRUCTION 359
XXIV. SUMMARY OF MECHANICAL PROGRESS 376
LIST OF ILLUSTRATIONS
THE DROP FORGE--FORGING A STEEL PLATE _Frontispiece_
FACING PAGE
RAISING WATER WITH A CHAIN OF POTS--A PRIMITIVE
PUMP USED IN EGYPT 32
HORSE-OPERATED CHAIN PUMP USED IN GREECE 32
MULTIPLE SPINDLE DRILL IN A MOTOR CAR FACTORY 33
BUCKET OF A GIANT DREDGE WITH ITS JAWS WIDE OPEN 64
GOLD DREDGE EATING ITS WAY THROUGH RIVER SANDS 65
SUCTION DREDGE EXCAVATING A CHANNEL AND BUILDING NEW LAND 65
AIR LOCK OF A PNEUMATIC CAISSON 96
SUBAQUEOUS TUNNEL SHOWING THE SHIELD IN THE BACKGROUND 97
WHARF PROTECTED BY A PNEUMATIC BREAKWATER 128
SUN-POWER PLANT IN EGYPT 129
CLOSE-UP OF ONE OF THE REFLECTORS OF A SUN-POWER PLANT 129
GIANT CAPRONI HYDROAEROPLANE 160
CONCRETE STEAMSHIP “FAITH” 161
“VIRGINIAN,” THE LARGEST LOCOMOTIVE IN THE WORLD 161
LOOM PROVIDED WITH A JACQUARD ATTACHMENT 224
BATTERY OF MULE SPINNING FRAMES 225
JACQUARD ATTACHMENT FOR LOOM 225
DIGGING A TRENCH WITH A MACHINE OF THE CHAIN TYPE 256
MULTIPLE PLOWING ON A WESTERN WHEAT FIELD 257
SAWING LOGS OF PULPWOOD INTO 16-INCH LENGTHS 288
HEATER IN A PULP MILL WHERE THE WOOD PULP IS MIXED WITH CLAY 288
MODERN FOURDRINIER PAPER-MAKING MACHINES 289
MOLTEN METAL FROM A BLAST FURNACE 320
BESSEMER CONVERTER BLOWING AIR THROUGH A MASS OF MOLTEN IRON 320
STEEL BEAM PASSING THROUGH THE FINISHING ROLLS 321
COMPOSITOR AT WORK ON A LINOTYPE MACHINE 352
THE OPTOPHONE, WHICH ENABLES THE BLIND TO READ PRINT 353
BLIND MAN READING WITH HIS EARS 353
CHAPTER I
TOOL-MAKING ANIMALS
WHEN we review the marvelous achievements of modern civilization we
are quite willing to agree with the ancient psalmist that man is
“little lower than the angels.” But at the other end of the scale our
complacency is liable to receive a rude shock; apparently the boundary
between man and beast is not so very easy to draw.
We used to be told that one important superiority of mankind lies in
the fact that he makes use of tools, while the beast never uses any
implement except those that nature has furnished him as part of his own
organism. But a gorilla will throw stones at his enemy; and he knows
how to brandish a club and use it with telling force. Some of the apes
are known to use sticks to knock down fruit which is out of the reach
of their hands, and they will crack nuts with a stone. Clearly these
animals are tool users. A very intelligent orang-utan in the Bronx
Zoölogical Garden, New York, after trying for days to wrench off a
bracket from the wall of his cage eventually used the horizontal bar of
his trapeze as a lever and with it pried the offending bracket from its
fastenings. Here was real invention and the discovery of the principle
of leverage. The great black arara cockatoo of New Guinea uses his beak
as a saw to weaken the shells of hard nuts, and to keep his bill from
slipping off the smooth shell he is ingenious enough to wrap a leaf
around the nut to hold it steady.
Even in the insect world we find creatures resourceful enough to make
use of tools. Prof. Franz Doflein of the University of Breslau tells
of an interesting study of certain ants, known as the _Oecophylla
smaragdina_, who build their nests in bushes by fastening leaves
together with fine threads. But the ants that build the nests cannot
spin these threads, because they possess no spinning glands. They must
depend upon their larvæ for this product. When a rent was made in one
of these nests, a band of the tiny creatures ranged themselves side
by side along the torn edge of the leaf and reached across the gap
until they could catch hold of the opposite edge with their mandibles.
Then they drew back step by step, with perfect teamwork, until the two
edges were brought together. In the meantime, other ants had rushed to
the nursery and each one had picked up a larva, not with the idea of
bearing it off to safety, but in order that the babies might spin the
thread which the adult ants were unable to do. The larvæ were carried
to the breach in the nest and moved back and forth across the rent.
They were pressed first against one side of the tear and then the other
and all the while were squeezed tightly, evidently with the purpose of
making them spin. Gradually a fine silky web was woven across the torn
leaf and eventually the rent was completely patched.
Unquestionably these little ants are tool-using animals, because they
make their larvæ serve as spinning spindles and also as weavers’
shuttles. However, this can hardly be cited as a point in common with
even the lowest type of man, for the ants merely use the tools they
find at their disposal. They certainly cannot be credited with having
produced or even improved the tool which they use, whereas even in
the most primitive of men we find that the tools used are not only
carefully selected for the work to be performed, but are actually,
shaped, be it ever so crudely, to suit the job.
Clearly we must shift the boundary between man and beast,
distinguishing the former as the creature who artificially improves his
tools. But even here it is not absolutely certain that the boundary
will stand. Wilhelm Boelsche, a well-known German writer on natural
history, calls attention to the “blacksmith woodpecker” which will
thrust hard pine nuts into cracks in the trunk of a tree, so that they
are held as if in a vise, enabling the bird to operate upon the seed
more easily. Furthermore, this woodpecker will actually make a hole in
the tree to receive the nut if there is not a hole or crack handy, so
that evidently this animal does produce or artificially improve the
tool that it uses.
There are a few such examples in nature, just enough to cast a bit of
uncertainty on the boundary we have set. But although the actual line
of demarcation may not be clear, there is no question but that the
lowest type of humanity now existent, or of which we have any record,
is or was a tool maker. Chipped stones evidently fashioned by man
for some useful purpose are found even in the remains of the Middle
Tertiary Epoch. The spirit of inquiry, of experiment, of invention,
and the ambition to dominate over other members of the animal kingdom
or over the obstacles imposed by nature, are to be found more or less
active among all peoples, no matter how lowly a position they may
occupy in the scale of civilization.
WAR AS A STIMULUS OF INVENTION
The most primitive implements were probably developed for the purpose
of war. From the very earliest times, down to the present day, war
has been a most potent stimulus of invention. The first tools ever
used were probably intended to enable the user to cope with dangerous
enemies. They marked the first stage in the conquest of brain over mere
brawn. The primitive weapons were used not only in fighting other men,
but in fighting off dangerous animals, and then in hunting animals for
food. No doubt the first implement ever used was a club, which gave
a real advantage over the unarmed, scratching, tearing, and biting
enemy. This was a lever which increased the reach of the fighter, and
also increased the power of his blow. The heavier the club, the more
dangerous the weapon, particularly when most of the weight was centered
at the outer end of the stick. But he was a real genius who first
fastened a rock to the end of his club.
THE ART OF BREAKING STONES
Then arose the art of breaking stones--breaking them skillfully, so as
to form a jagged cutting edge. When man began to fashion tools of stone
he left imperishable records of his craftsmanship which enable us to
trace his progress in invention. The first finished tool we find was
the fist hatchet--a stone roughly chipped to form a cutting edge and of
convenient shape for the grasp of the hand. This primitive tool very
slowly, through a period covering thousands of years, developed into
all manner of cutting implements, some with handles of wood and bone.
The ax head was followed by the spearhead and this finally by the
arrowhead, showing that man had at last found a mechanical substitute
for his muscles to hurl projectiles farther and with greater accuracy
than he could throw them by hand.
We marvel at the resourcefulness and skill of the primitive savage in
working so difficult a material as stone. It would baffle a modern
mechanic to be required to shape a piece of flint into an arrowhead
with no other tool than a piece of bone. He is so accustomed to using
tools which are harder than the material they are intended to shape
that he cannot conceive of making any impression upon a piece of flint
with a piece of bone, to say nothing of a stick of hard wood, and yet
such tools were used away back in the Stone Age. At first stones were
roughly shaped by hammering them together. Then the artisans became
more skilled. They discovered that certain stones could be chipped
more regularly and evenly, and the art of flaking off chips of flint
sprang up. Some specimens that belonged to ages long preceding that of
recorded history are beautifully done. The spearheads are symmetrically
shaped like a long narrow leaf, and the stone is evenly furrowed on
both sides with a keen edge all around.
Not only did primitive artisans shape the stone implements with hammer
blows, but they learned how to shape stone by pressure as well, using
a tool that was relatively soft. It is not a very difficult matter to
shape even so hard a substance as glass merely by pressure. If a piece
of glass is laid on a table with its edge slightly overhanging that of
the table, it is possible to chip off the overhanging edge by pressing
a nail or even a hard stick of wood against this edge. A small flake
of glass is thus removed, and, by continuing the process, arrowheads
of any shape may be formed. The tool is placed not against the upper
surface of the glass, but against the edge of the glass, so that only
the lower surface of it is split or flaked off. Then the glass is
turned over and a chip is taken off the opposite face.
In the Middle Stone Age we find the primitive craftsman equipped with
a very complete assortment of stone tools. He had hammers, chisels,
scrapers, drills, and polishing tools. He knew how to make useful
household implements, such as spoons and ladles, out of bone. He
polished his work and ornamented the implements with carvings of
animals. Ivory pins and needles show that he had begun to make himself
clothing from the skins of animals and that he sewed them together with
thongs or tendons.
In the Late Stone Age he had learned how to make vessels of fire-baked
clay. His axes were ground to a sharp edge, and he bored holes in the
ax head to receive the ax handle. The Swiss lake dwellers built houses
of wood and fitted them with all sorts of wooden furniture carved
with stone tools. Among the remains of these interesting settlements
may be found balls of clay which, from the fact that one of them was
discovered with a spool of flax still attached to it, were evidently
used as spinning “whorls” used for spinning flax into thread. Clothing
of skins was giving way to or being supplemented with clothing of woven
fabric.
DISCOVERY OF THE LEVER AND THE WEDGE
Prior to the Stone Age the club was undoubtedly used, in time of
peace--if there ever was a time of peace in those days--to batter down
trees, to beat through entanglements and to dislodge great stones.
Here the first idea of leverage was evidently employed. The club with
a rock tied to it, particularly if the rock was shaped with a sharp
edge, made a better implement for hewing trees. It is quite probable
that soon after this stage of development had been reached, some one
discovered the use of the wedge, particularly in splitting timber. Of
course, no one realized in those early days why it was that he could
pry up a greater weight with a lever than he could lift directly by
hand, or why he could split open a log by driving wedges into it. The
_art_ of mechanics was in existence long ages before _science_ of
mechanics began to be studied. But it was not until men began to look
into the why of things that rapid progress was made.
We can go on endlessly with our speculations on the evolution of tools
and machinery up to the time when historians began to record the
mechanical achievements of man. Unfortunately even after historians
began to write they were so filled with admiration for the destructive
work of man that they had no time to record his constructive work.
The warrior who spread havoc and terror received all the glory, and
his deeds were written on parchment, inscribed in clay and carved in
stone; but the humble artisan was not worthy of mention. Even when the
science of mechanics came to be studied, it was shrouded in a veil of
mystery, and it was beneath the dignity of the man of science to impart
his knowledge to the artisan. There was a lack of cooperation between
science and industry that has persisted to a certain extent even up
to the present time. Some of the most ingenious inventions of the
ancients were employed by a corrupt and crafty priesthood to produce
apparently miraculous effects and hoodwink the general public; and so,
in looking back to the early days of mechanics, we are obliged to draw
upon our imagination to trace its evolution, supplementing this by a
study of the tools of primitive people of more recent time. Practically
every form of hand tool we now use must have been known to the ancient
artisan.
INVENTION OF THE WHEEL
We are not going to attempt to write a history of the evolution of
machinery, but there is one invention whose origin is lost in the
remote prehistoric ages which deserves more than passing attention. It
is a pity that we have no clue as to who invented the wheel or how this
most important element that enters into the construction of nearly all
machinery was evolved. The invention called for a remarkable degree of
originality. There is nothing like a wheel in nature. Levers we have
in our own physical frame. But a wheel is something that is distinctly
a human creation. Whoever invented it must have been a real genius, a
James Watt or a Thomas Edison of his day. Certainly we owe more to the
invention of the wheel than we do even to so revolutionary a machine
as the steam engine, or the flying machine. How it was ever first
conceived is a mystery. Maybe this primeval genius got his idea from
seeing a stone rolling downhill, or he may have seen a tumbling weed
rolling along the ground before the wind. It may be that the forerunner
of the wheel was a roller shaped out of a log, for certainly primitive
civilization must have advanced enough to have known how to hew timber
before it would have been capable of fashioning a wheel. Some observant
man might have noticed that he could drag a heavy timber over a
rolling log much more easily than he could along the bare ground, and
gradually the roller evolved into a wheel.
We can speculate upon the evolution of vehicles and transportation,
once the wheel was invented. Of course, the first method of
transporting loads was to carry them in the arms. Possibly loads were
placed on skids and dragged along by one end. Away back in early times,
it was discovered that two persons could carry more than twice as much
as one, if the load were placed on a couple of poles. There was no
friction to contend with, and not only was the load cut in two, because
each man bore half of it, but the position of the load was such that
it could be borne more easily. After the wheel was discovered, some
one must have conceived of the idea of dispensing with an assistant by
placing a wheel between the poles of the stretcher, thus making a crude
wheelbarrow. It is more likely that two wheels were first used, making
a cart of the stretcher, because the crude workmen of those days could
hardly have produced anything but a very wobbly wheelbarrow. At any
rate, the wheel, or pair of wheels, robbed one man of his job. Only one
bearer was required where before two had been used. Labor costs were
immediately reduced 50 per cent.
DISPLACING MEN WITH MACHINES
In the very earliest days of invention machines began to displace men.
Had there been unions in those days, no doubt there would have been
strenuous opposition to the introduction of this substitute for an
honest worker. But among the ancients, even more than at the present
time, invention meant greater production rather than less work,
because the laborer of that time was not a hired man but a slave.
There was no object in cutting down labor when it cost practically
nothing. The only stimulus to invention was greater production.
The invention of the wheel meant the dawn of transportation, which
is the backbone of civilization, and from it resulted no end of
other inventions. It made it possible for communities to come into
closer touch with each other. It meant circulation--an interchange of
knowledge and of products. Food was transported from one locality to
another, enabling certain communities to dispense with agricultural
work and specialize in certain lines of manufacture; for they could
barter their products for food raised by other communities. There are
some tribes to-day which are most backward because they are separated
from other tribes by rivers, while other tribes similarly placed owe
their progress to the fact that they have developed sufficient skill to
build crude bridges and thus gain access to the outside world.
RAISING WATER
In Egypt the wheel had a wonderful effect on agriculture. In that dry
land water is, and always has been, most precious. No wonder the Nile
was venerated! It meant life--life to crops, and hence life to man.
How to raise water from this stream of life in time of drought was
the great problem of the Egyptian. As slave labor was cheap, it was
customary to haul up the precious water, a bucket at a time, and pour
it over the fields. Then some one discovered that this process could be
simplified by using a _shadoof_ or swape; in other words, a long pole
fulcrumed near one end, with a heavy rock for a counterbalance lashed
to the shorter arm, and a bucket tied by a long rope to the longer
arm of the lever. This primitive machine is still to be found in some
rural districts. With this contrivance, a heavier load could be lifted
than by hand, because, when raising the bucket, the weight of the rock
would assist in lifting the water. After the swape came all manner of
ingenious devices for lifting the water. There were seesaw arrangements
which would scoop up some of the water at each oscillation of the
seesaw, and in one ingenious contrivance there was a succession of
seesaws by which the water was raised to a considerable height, whence
it poured down into ditches that irrigated the fields.
Then some one invented a water wheel or a great wheel, fitted with
buckets, which was turned by human or ox power, and which poured a
steady stream of water into the irrigating ditches.
But the greatest invention was that of the engineer who actually made
the river turn the wheel. It was probably on the Nile that the _noria_,
as this machine was called, was first put into service.
The wheel was provided with paddles, so that the current made it
revolve, and the water spilled out of the buckets into a trough as
they were turned over by the wheel. We can imagine the triumph of the
ancient inventor who developed that machine. True, the river might
arise in its wrath now and then and wreck the machine, but in wrecking
the wheel it had to flood the land, which, after all, was exactly what
was aimed at. The anger of the river was short-lived; it soon quieted
down and went on placidly turning the wheel which robbed it of the
precious water. It was a great event in the history of engineering. The
Nile had been harnessed. One of the great powers of nature had been set
to work.