The material prosperity of the last century is due to
the co-operation of three classes of men: the man of
science, who lives only for truth and the discovery of
nature’s laws; the inventor, eager to apply these discoveries
to money-making machines and processes,
and the engineer, trained in mathematical investigation
and in knowledge of the physical conditions which govern
his profession, which is the mechanical application
of the laws of nature.
Engineering is sometimes divided into civil, military,
and naval engineering. The term civil engineering,
which will be here described, is often used by writers
as covering structural engineering only, but it has a
much wider meaning.
The logical classification is: statical engineering, including
that of all fixed bodies, and dynamical, covering
the movement of all bodies by the development and
application of power.
Statical engineering can be again subdivided into
structural engineering, or that of railways, highways,
bridges, foundations, tunnels, buildings, etc.; also,
into hydraulic engineering, which governs the application
of water to canals, river improvements, harbors,
the supply of water to towns and for irrigation, disposal
of sewage, etc.
Dynamical engineering can be divided into mechanical
engineering, which covers the construction of all prime
motors, the transmission of power, and the use of machines
and machine tools. Closely allied is electrical engineering,
the art of the transformation and transmission of
energy for traction, lighting, telegraphy, telephoning,
operating machinery, and many other uses, such as its
electrolytic application to ores and metals.
Then we have the combined application of statical,
mechanical, and electrical engineering to what is now
called industrial engineering, or the production of articles
useful to man. This may be divided into agricultural,
mining, metallurgical, and chemical engineering.
Surely this is a vast field, and can only be hastily described
in the sketch which we are about to give.
This is the oldest of all. We have not been able to
surpass the works of the past in grandeur or durability.
The pyramids of Egypt still stand, and will stand for
thousands of years. Roman bridges, aqueducts, and
sewers still perform their duties. Joseph’s canal still
irrigates Lower Egypt. The great wall of China, running
for fifteen hundred miles over mountains and plains,
contains one hundred and fifty millions of cubic yards
of materials and is the greatest of artificial works. No
modern building compares in grandeur with St. Peter’s,
and the mediæval cathedrals shame our puny imitations.
These mighty works were built to show the piety of
the Church or to gratify the pride of kings. Time and
money were of no account. All this has now been
changed. Capital controls, and the question of time,
money, and usefulness rules everything. Hence come
scientific design and labor-saving machinery.
The engineer of our modern works first calculates
the stresses on all their parts, and proportions them
accordingly, so that there is no waste of material. Hand
labor has given place to steam machinery. All parts
are interchangeable, so that they can be made and fitted
together in the least possible time, as is seen every day
in the construction of a steel-framed office building.
Our workmen receive much higher wages than in the
past, while time and cost have been diminished.
The greatest engineering work of the nineteenth
century was the development of the railway system
which has changed the face of the world. Beginning
in 1829 with the locomotive of George Stephenson, it
has extended with such strides that, after seventy years,
there are 466,000 miles of railways in the world, of
which 190,000 miles are in the United States. Their
cost is estimated at forty thousand millions of dollars,
of which ten thousand millions belong to the United
States.
The rapidity with which railways are built in the
United States and Canada contrasts strongly with what
has been done in other countries. Much has been written
of the energy of Russia in building 3000 miles of Siberian
railway in five or six years. In the United States an
average of 6147 miles was completed every year during
ten successive years, and in 1887 there were built 12,982
miles. The physical difficulties overcome in Siberia
are no greater than have been overcome here.
This rapid construction is due to several causes, the
most potent of which has been the need of extending
railways over great distances with little money. Hence
they were built economically, and at first in not as solid
a manner as those of Europe. Steeper gradients, sharper
curves, and lighter rails were used. This rendered
necessary a different kind of rolling-stock suitable to
such construction. The swivelling-truck and equalizing-beam
enabled our engines to run safely on tracks
where the rigid European engines would soon have
been in the ditch.
Our cars were made longer, and by the use of longitudinal
framing much stronger. A great economy
came from the use of annealed cast-iron wheels, with
hardened tires, all in one piece, instead of being built up
of spokes, hubs, and tires in separate parts. These wheels
now seldom break, and cost much less than European
wheels. As there are some eleven million car-wheels in
use in the United States the resulting economy is great.
It was soon seen that longer cars would carry a greater
proportion of paying load, and the more cars that one
engine could draw in a train, the less would be the cost.
It was not until the invention by Bessemer in 1864 of
a steel of quality and cost that made it available for
rails that much heavier cars and locomotives could be
used. Then came a rapid increase. As soon as Bessemer
rails were made in this country, the cost fell from
$175 per ton to $50, and now to $26.
Before that time a wooden car weighed sixteen tons,
and could carry a paying load of fifteen tons. The
thirty-ton engines of those days could not draw on a
level over thirty cars weighing 900 tons.
The pressed steel car of to-day weighs no more than
the wooden car, but carries a paying load of fifty tons.
The heaviest engines have now drawn on a level fifty
steel cars, weighing 3750 tons. In the one case the paying
load of an engine was 450 tons; now it is 2500 tons.
Steep grades soon developed a better brake system,
and these heavier trains have led to the invention of the
automatic brake worked from the engine, and also automatic
couplers, saving time and many lives. The capacity
of our railways has been greatly increased by
the use of electric block-signals.
The perfecting of both the railway and its rolling-stock
has led to remarkable results.
We have no accurate statistics of the early operation
of American railways. In 1867 Poor’s Manual estimated
their total freight tonnage at 75,000,000 and
the total freight receipts at $400,000,000. This was an
average rate per ton of $5.33.
In 1899 Poor gives the total freight tonnage at 975,789,941
tons, and the freight receipts at $922,436,314, or
an average rate per ton of ninety-five cents. Had the
rates of 1867 prevailed, the additional yearly cost to the
public would have been $4,275,000,000, or sufficient to
replace the whole railway system in two and a half years.
This is an illustration only, but a very striking one.
Everybody knows that such high rates of freight as
those of 1867 would have checked traffic. This much
can surely be said: the reduction in cost of operating
our railways, and the consequent fall in freight rates,
have been potent factors in enabling the United States
to send abroad last year $1,456,000,000 worth of exports
and flood the world with our food and manufactured
products.
In early days the building of a bridge was a matter of
great ceremony, and it was consecrated to protect it from
evil spirits. Its construction was controlled by priests,
as the title of the Pope of Rome, “Pontifex Maximus,”
indicates.
Railways changed all this. Instead of the picturesque
stone bridge, whose long line of low arches harmonized
with the landscape, there came the straight girder or
high truss, ugly indeed, but quickly built, and costing
much less.
Bridge construction has made greater progress in the
United States than abroad. The heavy trains that we
have described called for stronger bridges. The large
American rolling-stock is not used in England, and but
little on the continent of Europe, as the width of tunnels
and other obstacles will not allow of it. It is said that
there is an average of one bridge for every three miles of
railway in the United States, making 63,000 bridges,
most of which have been replaced by new and stronger
ones during the last twenty years.
This demand has brought into existence many bridge-building
companies, some of whom make the whole
bridge, from the ore to the finished product.
Before the advent of railways, highway bridges in
America were made of wood, and called trusses. Few
of them existed before railways. The large rivers and
estuaries were crossed in horse-boats, a trip more dangerous
than an Atlantic voyage now is. A few smaller
rivers had wooden truss bridges. Although originally
invented by Leonardo da Vinci, in the sixteenth century,
they were reinvented by American carpenters. Some
of Burr’s bridges are still standing after more than one
hundred years’ use. This shows what wood can do
when not overstrained and protected from weather and
fire.
The coming of railways required a stronger type of
bridge to carry concentrated loads, and the Howe truss,
with vertical iron rods, was invented, capable of 150-foot
spans.
About 1868 iron bridges began to take the place of
wooden bridges. Die-forged eyebars and pin connections
allowed of longer panels and longer spans. One of
the first long-span bridges was a single-track railway
bridge of 400-foot span over the Ohio at Cincinnati, which
was considered to be a great achievement in 1870.
The Kinzua viaduct, 310 feet high and over half a
mile long, belongs to this era. It is the type of the numerous
high viaducts now so common.
About 1885 a new material was given to engineers,
having greater strength and tenacity than iron, and
commercially available from its low cost. This is basic
steel. After many experiments, the proper proportions
of carbon, phosphorus, sulphur, and manganese were
ascertained, and uniformity resulted. The open-hearth
process is now generally used. This new chemical metal,
for such it is, is fifty per cent. stronger than iron,
and can be tied in a knot when cold.
The effect of improved devices and the use of steel is
shown by the weights of the 400-foot Ohio River iron
bridge, built in 1870, and a bridge at the same place,
built in 1886.
The bridge of 1870 was of iron, had panels twelve feet
long, and its height was forty-five feet, and span 400
feet.
The bridge of 1886 was of steel, had panels thirty feet
long, and its height was eighty feet. Its span was 550
feet. The weights of the two were nearly alike.
The cantilever design, which is a revival of a very
ancient type, came into use. The great Forth Bridge,
in Scotland, 1600-foot span, is of this style, as are the
500-foot spans at Poughkeepsie, and now a new one is
being designed to cross the St. Lawrence near Quebec,
of 1800-foot span.
This is probably near the economic limit of cantilever
construction, but the suspension bridge can be extended
much farther, as it carries no dead weight of compression
members.
The Niagara Suspension Bridge, of 810-foot span,
built by Roebling, in 1852, and the Brooklyn Bridge,
of 1600 feet, built by Roebling and his son, twenty years
after, marked a wonderful advance in bridge design.
Thirty years later, when a new bridge of 1600 feet
was wanted to cross another part of the East River at
New York, the same lines of construction were followed,
and they will be followed in the 2700-foot span, designed
to cross the North River some time in the present century.
The only radical advance is the use of a better
steel than could be had in earlier days.
Steel-arched bridges are now scientifically designed.
Such are the new Niagara Bridge, of 840-foot span, and
the Alexandra Bridge at Paris.
It is curious to see how little is said about these beautiful
bridges, which the public takes as a matter of course.
If they had been built fifty years ago, their engineers
would have received the same praise as Robert Stephenson
or Roebling, and justly so, as they would have been
men of exceptional genius. When these bridges were
built, in 1898, the path had been made so clear by mathematical
investigation and the command of a better
steel, that the task seemed easy.
That which marks more clearly than anything else
the great advance in American bridge building, during
the last forty years, is the reconstruction of the famous
Victoria Bridge, over the St. Lawrence, above Montreal.
This bridge was designed by Robert Stephenson, and the
stone piers are a monument to his engineering skill.
For forty winters they have resisted the great fields of
ice borne by a rapid current. Their dimensions were
so liberal that the new bridge was put upon them, although
four times as wide as the old one.
The superstructure was originally made of plate-iron
tubes, reinforced by tees and angles, similar to Stephenson’s
Menai Straits Bridge. There are twenty-two
spans of 240 feet each, and a central one of 330 feet.
Perhaps these tubes were the best that could be had at
the time, but they had outlived their usefulness. Their
interiors had become greatly corroded by the confined
gases from the engines and the drippings from the
chemicals used in cold-storage cars. Their height was
insufficient for modern large cars, and the confined
smoke made them so dark that the number of trains was
greatly limited.
It was decided to build a new bridge of open-work
construction and of open-hearth steel. This was done,
and the comparison is as follows: Old bridge, sixteen
feet wide, single track, live load of one ton per foot; new
bridge, sixty-seven feet wide, two railway tracks and
two carriage-ways, live load five tons per foot.
The old iron tubes weighed 10,000 tons, cost $2,713,000,
and took two seasons to erect. The new truss
bridge weighs 22,000 tons, has cost between $1,300,000
and $1,400,000, and the time of construction was one
year.
During his experience the writer has seen the rolling-load
of bridges increase from 2000 to 4000 pounds per
lineal foot of track, with an extra allowance for concentrated
loads.
The modern high office building is an interesting
example of the evolution of a high-viaduct pier. Such
a pier of the required dimensions, strengthened by more
columns strong enough to carry many floors, is the
skeleton frame. Enclose the sides with brick, stone, or
terra-cotta, add windows, and doors, and elevators, and
it is complete.
Fortunately for the stability of these high buildings,
the effect of wind pressures had been studied in this
country in the designs of the Kinzua, Pecos, and other
high viaducts.
All this had been thoroughly worked out and known
to our engineers before the fall of the Tay Bridge in
Scotland. That disastrous event led to very careful
experiments on wind pressures by Sir Benjamin Baker,
the very eminent engineer of the Forth Bridge. His
experiments showed that a wind gauge of 300 square
feet area showed a maximum pressure of thirty-five
pounds per square foot, while a small one of one foot
and a half square area registered gusts of forty-one
pounds per square foot.
The modern elevated railway of cities is simply a very
long railway viaduct. Some idea may be gained of the
life of a modern riveted-iron structure from the experience
of the Manhattan Elevated Railway of New
York. These roads were built in 1878–79 to carry uniform
loads of 1600 pounds per lineal foot, except Second
Avenue, which was made to carry 2000. The stresses
were below 10,000 pounds per square inch.
These viaducts have carried in twenty-two years over
25,000,000 trains, weighing over 3,000,000,000 tons, at a
maximum speed of twenty-five miles an hour, and are
still in good order.
Bridge engineers of the present day are free from the
difficulties which confronted the early designers of iron
bridges. The mathematics of bridge design was understood
in 1870, but the proportioning of details had
to be worked out individually. Every new span was a
new problem. Now the engineer tells his draughtsman
to design a span of a given length, height, and width,
and to carry such a load. By the light of experience he
does this at once.
Connections have become standardized so that the duplication
of parts can be carried to its fullest extent.
Machine tools are used to make every part of a bridge,
and power riveters to fasten them together. Great accuracy
can now be had, and the sizes of parts have increased
in a remarkable degree.
We have now great bridge companies, which are so
completely equipped with appliances for both shop drawings
and construction that the old joke becomes almost
true that they can make bridges and sell them by the mile.
All improvements of design are now public property.
All that the bridge companies do is done in the fierce
light of competition. Mistakes mean ruin, and the
fittest only survives.
Having such powerful aids, the American bridge
engineer of to-day has advantages over his predecessors
and over his European brethren, where the American
system has not yet been adopted.
The American system gives the greatest possible
rapidity of erection of the bridge on its piers. A span
of 518 feet, weighing 1000 tons, was erected at Cairo on
the Mississippi in six days. The parts were not assembled
until they were put upon the false works. European
engineers have sometimes ordered a bridge to be riveted
together complete in the maker’s yard, and then taken
apart.
The adoption of American work in such bridges as
the Atbara in South Africa, the Gokteik viaduct in Burmah,
320 feet high, and others, was due to low cost,
quick delivery and erection, as well as excellence of
material and construction.
Bridges must have foundations for their piers. Up
to the middle of the nineteenth century engineers knew
no better way of making them than by laying bare the
bed of the river by a pumped-out cofferdam, or by driving
piles into the sand, as Julius Cæsar did. About the
middle of the century, M. Triger, a French engineer, conceived
the first plan of a pneumatic foundation, which led
to the present system of compressing air by pumping it
into an inverted box, called a caisson, with air locks on
top to enable men and materials to go in and out. After
the soft materials were removed, and the caisson sunk
by its own weight to the proper depth, it was filled with
concrete. The limit of depth is that in which men can
work in compressed air without injury, and this is not
much over one hundred feet.
The foundations of the Brooklyn and St. Louis bridges
were put down in this manner.
In the construction of the Poughkeepsie bridge over
the Hudson in 1887–88, it became necessary to go down
135 feet below tide-level before hard bottom was reached.
Another process was invented to take the place of compressed
air. Timber caissons were built, having double
sides, and the spaces between them filled with stone to
give weight. Their tops were left open and the American
single-bucket dredge was used. This bucket was lowered
and lifted by a very long wire rope worked by the engine,
and with it the soft material was removed. By moving
this bucket to different parts of the caisson its sinking
was perfectly controlled, and the caisson finally placed in
its exact position, and perfectly vertical. The internal
space was then filled with concrete laid under water by
the same bucket, and levelled by divers when necessary.
While this work was going on, the government of New
South Wales, in Australia, called for both designs and
tenders for a bridge over an estuary of the sea called
Hawkesbury. The conditions were the same as at
Poughkeepsie, except that the soft mud reached to a
depth of 160 feet below tide-level.
The designs of the engineers of the Poughkeepsie
bridge were accepted, and the same method of sinking
open caissons (in this case made of iron) was carried
out with perfect success.
The erection of this bridge involved another difficult
problem. The mud was too soft and deep for piles and
staging, and the cantilever system in this site would
have increased the cost.
A staging was built on a large pontoon at the shore,
and the span erected upon it. The whole was then towed
out to the bridge site at high tide. As the tide fell, the
pontoon was lowered and the steel girder was placed
gently on its piers. The whole operation was completed
within six hours. The other five spans were
placed in the same manner.
The same system was followed afterwards by the engineer
of the Canadian Pacific Railway in placing the
spans of a bridge over the St. Lawrence, in a very rapid
current. It is now used in replacing old spans by new
ones, as it interrupts traffic for the least possible time.
The solution of the problems presented at Hawkesbury
gave the second introduction of American engineers to
bridge building outside of America. The first was in
1786, when an American carpenter or shipwright built
a bridge over Charles River at Boston, 1470 feet long by
forty-six feet wide. This bridge was of wood supported
on piles. His work gained for him such renown that
he was called to Ireland and built a similar bridge at
Belfast.
Tunnelling by compressed air is a horizontal application
of compressed-air foundations. The earth is supported
by an iron tube, which is added to in rings, which
are pushed forward by hydraulic jacks.
A tunnel is now being made under an arm of the sea
between Boston and East Boston, some 1400 feet long
and sixty-five feet below tide. The interior lining of
iron tubing is not used. The tunnel is built of concrete,
reinforced by steel rods. This will effect a considerable
economy. Success in modern engineering means doing a
thing in the most economical way consistent with safety.
The Saint Clair tunnel, which carries the Grand Trunk
Railway of Canada under the outlet of Lake Huron,
is a successful example of such work. Had the North
River tunnel, at New York, been designed on equally
scientific principles, it would probably have been finished,
which now seems problematical.
The construction of rapid-transit railways in cities
is another branch of engineering, covering structural,
mechanical, and electrical engineering. Some of these
railways are elevated, and are merely railway viaducts,
but the favorite type now is that of subways. There
are two kinds, those near the surface, like the District
railways of London, the subways in Paris, Berlin, and
Boston, and that now building in New York. The
South London and Central London, and other London
projects, are tubes sunk fifty to eighty feet below the
surface and requiring elevators for access. These are
made on a plan devised by Greathead, and consist of
cast-iron tubes pushed forward by hydraulic rams, and
having the space outside of the tube filled with liquid
cement pumped into place.
The construction of the Boston subway was difficult
on account of the small width of the streets, their great
traffic, and the necessity of underpinning the foundations
of buildings. All of this was successfully done
without disturbing the traffic for a single day, and reflects
great credit on the engineer. Owing to the great
width of New York streets, the problem is simpler in
that respect, but requires skill in design and organization
to complete the work in a short time. Although
many times as long as the Boston subway, it will be built
in nearly the same time. The design, where in earth,
may be compared to that of a steel office building twenty
miles long, laid flat on one of its sides. The reduplication
of parts saves time and labor, and is the key to the
anticipated rapid progress. Near the surface this subway
is built in open excavation, and tunnelling is confined
to rock.
The construction of power-houses for developing energy
from coal and from falling water requires much
structural besides electrical and mechanical engineering
ability. The Niagara power-house is intended to develop
100,000 horse-power; that at the Sault Ste. Marie
as much; that on the St. Lawrence, at Massena, 70,000
horse-power. These are huge works, requiring tunnels,
rock-cut chambers, and masonry and concrete in walls
and dams. They cover large extents of territory.
The contrast in size of the coal-using power-houses
is interesting. The new power-house now building
by the Manhattan Elevated Railway, in New York, develops
in the small space of 200 by 400 feet 100,000 horse-power,
or as much power as that utilized at Niagara Falls.
One of the most useful materials which modern engineers
now make use of is concrete, which can be put into
confined spaces and laid under water. It costs less
than masonry, while as strong. This is the revival of
the use of a material used by the Romans. The writer
was once allowed to climb a ladder and look at the construction
of a dome of the Pantheon, at Rome. He
found it a monolithic mass of concrete, and hence without
thrust. It is a better piece of engineering construction
than the dome of St. Peter’s, built fifteen hundred
years later. The dome of Columbia College Library, in
New York, is built of concrete.
Concrete is a mixture of broken stone or gravel, sand,
and Portland cement. Its virtue depends upon the
uniform good quality of the cement. The use of the
rotary kiln, which exposes all the contained material to
a uniform and constant intense heat, has revolutionized
the manufacture of Portland cement. The engineer
can now depend upon its uniformity of strength.
Wheels, axles, bridges, and rails have all been strengthened
to carry their increased loads; but, strange to say,
the splices which hold in place the ends of the rails, and
which are really short-span bridges, are now the weakest
part of a railway. The angle-bar splice has but one-third
of the strength of the rail, and its strength cannot
be increased, owing to its want of depth. Joints go
down under every passing wheel, and the ends of the
rails wear out long before the rest.
This is not an insignificant detail. It has been estimated
by the officers of one of the trunk lines that a splice
of proper design and strength would save yearly enough
in track labor (most of which is expended in tamping up
low joints) to buy all the new rails and fastenings required
in some time. It would save much more than
that in the wear of rolling-stock. A perfect joint would
be an economic device next in value to the Bessemer
steel rail. Here is a place for scientific and practical
skill.
This is one of the oldest branches of engineering, and
was developed before the last century. The irrigation
works of Asia, Africa, Spain, Italy, the Roman aqueducts,
and the canals of Europe, are examples. Hydraulic
works cannot be constructed in ignorance of the
laws which govern the flow of water. The action of
water is relentless, as ruined canals, obstructed rivers,
and washed-out dams testify.
The principal additions of the nineteenth century to
hydraulic engineering are the collection of larger statistics
of the flow of water in pipes and channels, of rainfall,
run-off, and available supply. It is now known
that the germs of disease can be retained by ordinary
sand filters, and it is now an established fact that pure
drinking water and proper drainage are a sure preventive
of typhoid and similar fevers. Very foul water can be
made potable. Experiments show that the water of the
Schuylkill River at Philadelphia, which contains 400,000
germs in the space of less than a cubic inch, was so
much purified by filtering that only sixty remained.
This is a discovery of sanitary science, but the application
of it is through structural engineering, which designs
and executes the filter beds with great economy.
The removal of sewage, after having been done by
the Etruscans before the foundation of Rome, became a
lost art during the dirty Dark Ages, when filth and piety
were deemed to be connected in some mysterious way.
It was reserved for good John Wesley to point out that
“Cleanliness is next to godliness.” Now sewage works
are as common as those for water supply. Some of them
have been of great size and cost. Such are the drainage
works of London, Paris, Berlin, Boston, Chicago, and
New Orleans. A very difficult work was the drainage
of the City of Mexico, which is in a valley surrounded
by mountains, and elevated only four to five feet above a
lake having no outlet. Attempts to drain the lake had
been made in vain for six hundred years. It has lately
been accomplished by a tunnel six miles long through
the mountains, and a canal of over thirty miles, the whole
work costing some $20,000,000.
The drainage of Chicago by locks and canal into the
Illinois River has cost some $35,000,000, and is well
worth its cost.
Scientific research has been applied to the designing
of high masonry and concrete dams, and we know now
that no well-designed dam on a good foundation should
fail. The dams now building across the Nile by order
of the British government will create the largest artificial
lakes in the world. The water thus stored will
be of inestimable value in irrigating the crops of Lower
Egypt. Their cost, although great, will not exceed the
sums spent by the lavish Khedive Ismail on useless
palaces, now falling to decay.
The Suez Canal is one of the largest hydraulic works
of the last century, and is a notable instance of the displacement
of hand labor by the use of machinery. Ismail
began by impressing a large part of the peasant
population of Egypt, just as Rameses had done over
3000 years before. These unfortunate people were
set to dig the sand with rude hoes, and carry it
away in baskets on their heads. They died by thousands
for want of water and proper food. At last the
French engineers persuaded the Khedive to let them introduce
steam dredging machinery. A light railway
was laid to supply provisions, and a small ditch dug to
bring pure water. The number of men employed fell
to one-fourth. Machinery did the rest. But for this
the canal would never have been finished.
The Panama Canal now uses the best modern machinery,
and the Nicaragua Canal, if built, will apply
still better methods, developed on the Chicago drainage
canal, where material was handled at a less cost than
has ever been done before.
Russia is better supplied with internal waterways than
any other country. Her rivers rise near each other, and
have long been connected by canals. It is stated that
she has over 60,000 miles of internal navigation, and
is now preparing the construction of canals to connect
the Caspian with the Baltic Sea.
The Erie Canal was one of very small cost, but its
influence has been surpassed by none. The “winning
of the West” was hastened many years by the construction
of this work in the first quarter of the century.
Two horses were just able to draw a ton of goods at the
speed of two miles an hour over the wretched roads of
those days. When the canal was made these two horses
could draw a boat carrying 150 tons four miles an hour.
Mud, or, in other words, friction, is the great enemy of
civilization, and canals were the first things to diminish
it, and after that railways.
The Erie Canal was made by engineers, but it had to
make its own engineers first, as there were none available
in this country at that time. These self-taught men,
some of them land surveyors and others lawyers, showed
themselves the equals of the Englishmen Brindley and
Smeaton, when they located a water route through the
wilderness, having a uniform descent from Lake Erie
to the Hudson, and which would have been so built if
there had been enough money.
The question now is whether to enlarge the capacity
of this canal by enlarging its prism and locks, or to increase
speed and move more boats in a season by electrical
appliances. The last method seems more in line
with those of the present day.
There should be a waterway from the Hudson to Lake
Erie large enough for vessels able to navigate the lakes
and the ocean. A draft of twenty-one feet can be had
at a cost estimated at $200,000,000.
The deepening of the Chicago drainage canal to the
Mississippi River, and the deepening of the Mississippi
itself to the Gulf of Mexico, is a logical sequence of the
first project. The Nicaragua Canal would then form
one part of a great line of navigation, by which the
products of the interior of the continent could reach
either the Atlantic or Pacific Ocean.
The cost would be small compared with the resulting
benefits, and some day this navigation will be built by
the government of the United States.
The deepening of the Southwest Pass of the Mississippi
River from six to thirty feet by James B. Eads was a
great engineering achievement. It was the first application
of the jetty system on a large scale. This is merely
confining the flow of a river, and thus increasing its
velocity so that it secures a deeper channel for itself.
The improvement of harbors follows closely the increased
size of ocean and lake vessels. The approach
to New York harbor is now being deepened to forty feet,
a thing impossible to be done without the largest application
of steam machinery in a suction dredge boat.
The great increase of urban population, due to steam
and electric railways, has made works of water supply
and drainage necessary everywhere. Some of these
are on a very grand scale. An illustration of this is
the Croton Aqueduct of New York as it now is, and as it
will be hereafter.
This work was thought by its designers to be on a
scale large enough to last for all time. It is now less
than sixty years old, and the population of New York
will soon be too large to be supplied by it.
It is able to supply 250,000,000 to 300,000,000 gallons
daily, and its cost, when the Cornell dam and Jerome
Park reservoir are finished, will be a little over $92,000,000.
It is now suggested to store water in the Adirondack
Mountains, 203 miles away, by dams built at the outlet
of ten or twelve lakes. This will equalize the flow of
the Hudson River so as to give 3,000,000,000 to 4,000,000,000
gallons daily. It is then proposed to pump
1,000,000,000 gallons daily from the Hudson River at
Poughkeepsie, sixty miles away, to a height sufficient
to supply the city by gravity through an aqueduct.
This water would be filtered at Poughkeepsie, and we
now know that all impurities can be removed.
If this scheme is carried out, the total supply will be
about 1,300,000,000 gallons daily, or enough for a population
of from 12,000,000 to 13,000,000 persons. By
putting in more pumps, filter-beds, and conduits, this
supply can be increased forty per cent., or to 1,800,000,000
gallons daily. This water would fill every day a lake
one mile square by ten feet deep. This is a fair example
of the scale of the engineering works of the nineteenth
and twentieth centuries.
By the application of modern labor-saving machinery,
the cost of this work can be so far controlled that the cost
to the city of New York per 1,000,000 gallons would
be no greater than that of the present Croton supply.
All works of hydraulic engineers depend on water.
But what will happen if the water all dries up? India,
China, Spain, Turkey, and Syria have suffered from
droughts, caused clearly by the destruction of their
forests. The demand for paper to print books and newspapers
upon, and for other purposes, is fast converting
our forests into pulp. We cannot even say, “After us
the deluge,” for it will seldom rain in those evil days.
When the rains do come, the sponge-like vegetation of
the forests being gone, the streams will be torrents at
one time of the year and dried up during the rest, as we
now see in the arid regions of the West.
This is employed in all dynamical engineering. It
covers the designs of prime motors of all sorts, steam,
gas, and gasoline reciprocating engines; also steam
and water turbines, wind-mills, and wave-motors.
It comprises all means of transmitting power, as by
shafting, ropes, pneumatic pressure, and compressed
air, all of which seem likely to be superseded by electricity.
It covers the construction of machine tools and machinery
of all kinds. It enters into all the processes of
structural, hydraulic, electrical, and industrial engineering.
The special improvements are: The almost
universal use of rotary motion, and of the reduplication
of parts.
The steam-engine is a machine of reciprocating, converted
into rotary, motion by the crank. The progress
of mechanical engineering during the nineteenth century
is measured by the improvements of the steam-engine,
principally in the direction of saving fuel, by the
invention of internal combustion or gas-engines, the
application of electrical transmission, and, latest, the
practical development of steam turbines by Parsons,
Westinghouse, Delaval, Curtis, and others. In these
a jet of steam impinges upon buckets set upon the circumference
of a wheel. It was clearly indicated by the
Italian engineer Bronca, in 1629, but he was too early.
The time was not ripe, and there were then no machine
tools giving the perfection of workmanship required.
Their advantages are that their motion is rotary and
not reciprocal. They can develop speed of from 5000
to 30,000 revolutions per minute, while the highest
ever attained by a reciprocating engine is not over
1000. Their thermodynamic losses are less, hence they
consume less steam and less fuel.
It is a very interesting fact that the basic invention
upon which not only steam turbines and electric dynamos,
but, indeed, all other parts of mechanical engineering,
depend, is of such remote antiquity that we know
nothing of its origin. This is the wheel which Gladstone
said was the greatest of man’s mechanical inventions,
as there is nothing in nature to suggest it.
Duplication of parts has lowered the cost of all products.
Clothing is one of these. The parts of ready-made garments
and shoes are now cut into shape in numbers at
a time, by sharp-edged templates, and then fastened
together by sewing-machines.
Mechanical engineering is a good example of the
survival of the fittest. Millions of dollars are expended
on machinery, when suddenly a new discovery or invention
casts them all into the scrap heap, to be replaced
by those of greater earning capacity.
Prime motors derive their energy either from coal
or other combinations of carbon, such as petroleum, or
from gravity. This may come from falling water, and
the old-fashioned water-wheels of the eighteenth century
were superseded in the nineteenth by turbines, first invented
in France and since greatly perfected. These
are used in the electrical transmission of water-power at
Niagara of 5000 horse-power, and form a very important
part of the plant.
The other gravity motors are wind-mills and wave-motors.
Wind-mills are an old invention, but have
been greatly improved in the United States by the use
of the self-reefing wheel. The great plains of the West
are subject to sudden, violent gales of wind, and unless
the wheel was automatically self-reefing it would often
be destroyed. Little has been written about these wheels,
but their use is very widely extended, and they perform
a most useful function in industrial engineering.
There have been vast numbers of patents taken out
for wave-motors. One was invented in Chili, South
America, which furnished a constant power for four
months, and was utilized in sawing planks. The action
of waves is more constant on the Pacific coast of America
than elsewhere, and some auxiliary power, such as a
gasoline engine, which can be quickly started and stopped,
must be provided for use during calm days. The
prime cost of such a machine need not exceed that of a
steam plant, and the cost of operating is much less than
that of any fuel-burning engine. The saving of coal
is a very important problem. In a wider sense, we may
say that the saving of all the great stores which nature
has laid up for us during the past, and which have remained
almost untouched until the nineteenth century,
is the great problem of to-day.
Petroleum and natural gas may disappear. The
ores of gold, silver, and platinum will not last forever.
Trees will grow, and iron ores seem to be practically
inexhaustible. Chemistry has added a new metal in
aluminum, which replaces copper for many purposes.
One of the greatest problems of the twentieth century
is to discover some chemical process for treating iron,
by which oxidation will not take place.
Coal, next to grain, is the most important of nature’s
gifts; it can be exhausted, or the cost of mining it become
so great that it cannot be obtained in the countries where
it is most needed; water, wind, and wave power may
take its place to a limited extent, and greater use may
be made of the waste gases coming from blast or smelter
furnaces, but as nearly all energy comes from coal,
its use must be economized, and the greatest economy
will come from pulverizing coal and using it in the shape
of a fine powder. Inventions have been made trying
to deliver this powder into the fire-box as fast as made,
for it is as explosive as gunpowder, and as dangerous
to store or handle. If this can be done, there will be a
saving of coal due to perfect and smokeless combustion,
as the admission of air can be entirely regulated, the
same blast which throws in the powder furnishing oxygen.
Some investigators have estimated that the saving of
coal will be as great as twenty per cent. This means
100,000,000 tons of coal annually.
Bituminous coal will then be as smokeless as anthracite,
and can be burned in locomotives. Cities will be free
from the nuisance of wasted coal, which we call soot.
This process will be the best kind of mechanical stoking,
and will prevent the necessity of opening the doors of
fire-boxes. The boiler-rooms of steamships will no
longer be “floating hells,” and the firing of large locomotives
will become easy.
Another problem of mechanical engineering is to
determine whether it will be found more economical to
transform the energy of coal, at the mines, into electric
current and send it by wire to cities and other places
where it is wanted, or to carry the coal by rail and water,
as we now do, to such places, and convert it there by the
steam or gas engine.
In favor of the first method it can be said that hills
of refuse coal now representing locked-up capital can
be burned, and the cost of transportation and handling
be saved. Electric energy can now transport power
in high voltage economically between coal-mines and
most large cities.
The second method has the advantage of not depending
on one single source of supply, that may break down,
but in having the energy stored in coal-pockets near
by the place of use, where it can be applied to separate
units of power with no fear of failure.
It seems probable that a combination of the two systems
will produce the best results. Where power can be
sent electrically from the mines for less cost than the
coal can be transported, that method will be used.
To prevent stoppage of works, the separate motors
and a store of coal, to be used in cases of emergency,
will still be needed, just as has been described as necessary
to the commercial success of wave-motors.
Any attempt by the writer of this article to trace the
progress of electricity would be but a vain repetition,
after the admirable manner in which the subject has
been treated in a former paper of this series by Professor
Elihu Thomson.
We can only once more emphasize the fact that it is
by the union of four separate classes of minds—scientific
discoverers, inventors, engineers, and capitalists—that
this vast new industry has been created, which gives
direct employment to thousands, and, as Bacon said
300 years ago, has “endowed the human race with new
powers.”
All the processes of metallurgy and mining employ
statical, hydraulic, mechanical, and electrical engineering.
Coal, without railways and canals, would be of
little use, unless electrical engineering came to its aid.
It was estimated by the late Lord Armstrong that of
the 450,000,000 to 500,000,000 tons of coal annually produced
in the world, one-third is used for steam production,
one-third in metallurgical processes, and one-third
for domestic consumption. This last item seems
large. It is the most important manufacturing industry
in the world, as may be seen by comparing the coalless
condition of the eighteenth century with the coal-using
condition of the nineteenth century.
Next in importance comes the production of iron and
steel. Steel, on account of its great cost and brittleness,
was only used for tools and special purposes until past
the middle of the last century. This has been all changed
by the invention of his steel by Bessemer in 1864, and
open-hearth steel in the furnace of Siemens, perfected
some twenty years since by Gilchrist & Thomas.
The United States have taken the lead in steel manufacture.
In 1873 Great Britain made three times as
much steel as the United States. Now the United States
makes twice as much as Great Britain, or forty per cent.
of all the steel made in the world.
Mr. Carnegie has explained the reason why, in epigrammatic
phrase: “Three pounds of steel billets can
be sold for two cents.”
This stimulates rail and water traffic and other industries,
as he tells us one pound of steel requires two
pounds of ore, one and one-third pounds of coal, and one-third
of a pound of limestone.
It is not surprising, therefore, that the States bordering
on the lakes have created a traffic of 25,000,000 tons
yearly through the Sault Ste. Marie Canal, while the
Suez, which supplies the wants of half the population of
the world, has only 7,000,000, or less than the tonnage
of the little Harlem River at New York.
This leads us to our last topic, for which too little room
has been left. Industrial engineering covers statical,
hydraulic, mechanical, and electrical engineering, and
adds a new branch which we may call chemical engineering.
This is pre-eminently a child of the nineteenth
century, and is the conversion of one thing into another
by a knowledge of their chemical constituents.
When Dalton first applied mathematics to chemistry
and made it quantitative, he gave the key which led to
the discoveries of Cavendish, Gay-Lussac, Berzelius,
Liebig, and others. This new knowledge was not locked
up, but at once given to the world, and made use of. Its
first application on a large scale was made by Napoleon
in encouraging the manufacture of sugar from beets.
The new products were generally made from what
were called “waste material.” We now have the manufacture
of soda, bleaching powders, aniline dyes, and
other products of the distillation of coal, also coal-oil
from petroleum (known fifty or sixty years ago only as a
horse medicine), acetylene gas, celluloid, rubber goods
in all their numerous varieties, high explosives, cement,
artificial manures, artificial ice, beet-sugar, and even
beer may now be included.
Through many ages, the alchemists, groping in the
dark, and in ignorance of nature’s laws, wasted their
time in trying to find what they called the philosopher’s
stone, which they hoped would transform the baser
metals into gold.
If such a thing could be found it would be a curse, as
it would take away one of the most useful instruments
we have—a fixed standard of value.
In a little over one hundred years, those working by
the light of science have found the true philosopher’s
stone in modern chemistry. The value of only a part of
these new products exceeds the nominal value of all the
gold in the world.
The value of our mechanical and chemical products is
great, but it is surpassed by that of food products. If
these did not keep pace with the increase of population,
the theories of Malthus would be true—but he never saw
a modern reaper.
The steam-plough was invented in England some
fifty years since, but the great use of agricultural machinery
dates from our Civil War, when so many men
were taken from agriculture. It became necessary to
fill their places with machinery. Without tracing the
steps which have led to it, we may say that the common
type is what is called “the binder,” and is a machine
drawn chiefly by animals, and in some cases by a field
locomotive.
It cuts, rakes, and binds sheaves of grain at one operation.
Sometimes threshing and winnowing machines
are combined with it, and the grain is delivered
into bags ready for the market.
Different machines are used for cutting and binding
corn, and for mowing and raking hay, but the most important
of all is the grain-binder. The extent of their
use may be known from the fact that 75,000 tons of
twine are used by these machines annually.
It is estimated that there are in the United States
1,500,000 of these machines, but as the harvest is
earlier in the South, there are probably not over 1,000,000
in use at one time. As each machine takes the
place of sixteen men, this means that 16,000,000 men
are released from farming for other pursuits.
The “man with the hoe” has disappeared from the
real world, and is only to be found in the dreams of poets.
It is fair to assume that a large part of these 16,000,000
men have gone into manufacturing, the
operating of railways, and other pursuits. The use
of agricultural machinery, therefore, is one explanation
of why the United States produces eight-tenths of the
world’s cotton and corn, one-quarter of its wheat, one-third
of its meat and iron, two-fifths of its steel, and one-third
of its coal, and a large part of the world’s manufactured
goods.
It is a very interesting question, why was this great
development of material prosperity delayed so late?
Why did it wait until the nineteenth century, and then
all at once increase with such rapid strides?
It was not until modern times that the reign of law
was greatly extended, and men were insured the product
of their labors.
Then came the union of scientists, inventors, and
engineers.
So long as these three classes worked separately but
little was done. There was an antagonism between
them. Ancient writers went so far as to say that the
invention of the arch and of the potter’s wheel were beneath
the dignity of a philosopher.
One of the first great men to take a different view was
Francis Bacon. Macaulay, in his famous essay, quotes
him as saying: “Philosophy is the relief of man’s estate,
and the endowment of the human race with new powers;
increasing their pleasures and mitigating their sufferings.”
These noble words seem to anticipate the famous
definition of civil engineering, embodied by Telford
in the charter of the British Institution of Civil Engineers:
“Engineering is the art of controlling the great
powers of nature for the use and convenience of man.”
The seed sown by Bacon was long in producing fruit.
Until the laws of nature were better known, there could
be no practical application of them. Towards the end
of the eighteenth century a great intellectual revival
took place. In literature appeared Voltaire, Rousseau,
Kant, Hume, and Goethe. In pure science there came
Laplace, Cavendish, Lavoisier, Linnæus, Berzelius,
Priestley, Count Rumford, James Watt, and Dr. Franklin.
The last three were among the earliest to bring
about a union of pure and applied science. Franklin
immediately applied his discovery that frictional electricity
and lightning were the same to the protection
of buildings by lightning-rods. Count Rumford (whose
experiments on the conversion of power into heat led
to the discovery of the conservatism of energy) spent a
long life in contriving useful inventions.
James Watt, one of the few men who have united in
themselves knowledge of abstract science, great inventive
faculties, and rare mechanical skill, changed the
steam-engine from a worthless rattletrap into the most
useful machine ever invented by man. To do this he
first discovered the science of thermodynamics, then
invented the necessary appliances, and finally constructed
them with his own hands. He was a very exceptional
man. At the beginning of the nineteenth
century there were few engineers who had received any
scientific education. Most of them worked by their
constructive instincts, like beavers, or from experience
only. It took a lifetime to educate such an engineer,
and few became eminent until they were old men.
Now there is in the profession a great army of young
men, most of them graduates of technical schools, good
mathematicians, and well versed in the art of experimenting.
The experiments of undergraduates on cements,
concrete, the flow of water, the impact of metals,
and the steam-engine, have added much to the general
stock of knowledge.
One of the present causes of progress is that all discoveries
are published at once in technical journals and
in the daily press. The publication of descriptive indexes
of all scientific and engineering articles as fast
as they appear is another modern contrivance.
Formerly scientific discoveries were concealed by
cryptograms, printed in a dead language, and hidden in
the archives of learned societies. Even so late as 1821
Oersted published his discovery of the uniformity of
electricity and magnetism in Latin.
Engineering works could have been designed and
useful inventions made, but they could not have been
carried out without combination. Corporate organization
collects the small savings of many into great sums
through savings-banks, life insurance companies, etc.,
and uses this concentrated capital to construct the vast
works of our days. This could not continue unless
fair dividends were paid. Everything now has to be
designed so as to pay. Time, labor, and material must
be saved, and he ranks highest who can best do this.
Invention has been encouraged by liberal patent laws,
which secure to the inventor property in his ideas at a
moderate cost.
Combination, organization, and scientific discovery,
inventive ability, and engineering skill are now united.
It may be said that we have gathered together all
the inventions of the nineteenth century and called
them works of engineering. This is not so. Engineering
covers much more than invention. It includes all
works of sufficient size and intricacy to require men
trained in the knowledge of the physical conditions
which govern the mechanical application of the laws
of nature. First comes scientific discovery, then invention,
and lastly engineering. Faraday and Henry
discovered the electrical laws which led to the invention
of the dynamo, which was perfected by many minds.
Engineering built such works as those at Niagara Falls
to make it useful.
An ignorant man may invent a safety-pin, but he
cannot build the Brooklyn Bridge.
The engineer-in-chief commands an army of experts,
as without specialization little can be done. His is the
comprehensive design, for which he alone is responsible.
Such is the evolution of engineering, which began
as a craft and has ended as a profession.
In past times, civilization depended upon military
engineering. Warriors at first used only the weapons
of the hand. Then came military engineering, applied
both to attack and defence, and culminating in the invention
of gunpowder. The civilization of to-day depends
greatly upon civil engineering, as we have tried
to show. It has changed the face of the world and
brought all men nearer together. It has improved
the condition of man by sanitary appliances and lowering
the cost of food. It has shown that through machinery
the workman is better educated, and his wages are
increased, while the profits of capital increase also.
It has made representative government possible over
vast areas of territory, and is democratizing the world.
Thoughtful persons have asked, will this new civilization
last, or will it go the way of its predecessors? Surely
the answer is: all depends on good government, on the
stability of law, order, and justice, protecting the rights
of all classes. It will continue to grow with the growth
of good government, prosper with its prosperity, and
perish with its decay.
Thomas C. Clarke.