[It has been ascertained by statistical observation that in engineering enterprises one man is killed for every million francs that is spent on the works.] Supposing you have to build a bridge at an expense of one hundred million francs, you must be prepared for the death of one hundred men. In building the Eiffel Tower, which was a construction costing six million and a half, we only lost four men, thus remaining below the average. In the construction of the Forth Bridge, 55 men were lost in over 45,000,000 francs’ worth of work. That would appear to be a large number according to the general rule, but when the special risks are remembered, this number shows as a very small one.

[Large motorway flyovers] are the cathedrals of the modern world.

[Presently, science undergraduates] do not learn to write clearly and briefly, marshalling their points in due and aesthetically satisfying order, and eliminating inessentials. They are inept at those turns of phrase or happy analogy which throw a flying bridge across a chasm of misunderstanding and make contact between mind and mind.

[The ancient monuments] were all dwarfs in size and pigmies in spirit beside this mighty Statue of Liberty, and its inspiring thought. Higher than the monument in Trafalgar Square which commemorates the victories of Nelson on the sea; higher than the Column Vendome, which perpetuates the triumphs of Napoleon on the land; higher than the towers of the Brooklyn Bridge, which exhibit the latest and greatest results of science, invention, and industrial progress, this structure rises toward the heavens to illustrate an idea ... which inspired the charter in the cabin of the Mayflower and the Declaration of Independence from the Continental Congress.

[The French Academy of Sciences is] the receptacle of a crowd of mediocrities and ignoramuses whose places have been made as college professors, herb collectors, village veterinarians and assistant engineers of bridges and roads.

The Mighty Task is Done

At last the mighty task is done;
Resplendent in the western sun
The Bridge looms mountain high;
Its titan piers grip ocean floor,
Its great steel arms link shore with shore,
Its towers pierce the sky.

On its broad decks in rightful pride,
The world in swift parade shall ride,
Throughout all time to be;
Beneath, fleet ships from every port,
Vast landlocked bay, historic fort,
And dwarfing all the sea.

To north, the Redwood Empires gates;
To south, a happy playground waits,
In Rapturous appeal;
Here nature, free since time began,
Yields to the restless moods of man,
Accepts his bonds of steel.

Launched midst a thousand hopes and fears,
Damned by a thousand hostile sneers,
Yet Neer its course was stayed,
But ask of those who met the foe
Who stood alone when faith was low,
Ask them the price they paid.

Ask of the steel, each strut and wire,
Ask of the searching, purging fire,
That marked their natal hour;
Ask of the mind, the hand, the heart,
Ask of each single, stalwart part,
What gave it force and power.

An Honored cause and nobly fought
And that which they so bravely wrought,
Now glorifies their deed,
No selfish urge shall stain its life,
Nor envy, greed, intrigue, nor strife,
Nor false, ignoble creed.

High overhead its lights shall gleam,
Far, far below lifes restless stream,
Unceasingly shall flow;
For this was spun its lithe fine form,
To fear not war, nor time, nor storm,
For Fate had meant it so.

Engineering, too, owes its most useful materials to the achievements of chemists in identifying, separating, and transforming materials: structural steel for the framework of bridges and buildings, portland cement for roadways and aqueducts, pure copper for the electrical industries, aluminum alloys for automobiles and airplanes, porcelain for spark plugs and electrical insulators. The triumphs of engineering skill rest on a chemical foundation.

Les grands ponts étant … des monuments qui peuvent servir à faire connoître la magnificence et le génie d’une nation, on ne sauroit trop s’occuper des moyens d’en perfectionner l’architecture, qui peut d’ailleurs être susceptible de variété, en conservant toujours, dans les formes et la décoration, le caractere de solidité qui lui est propre.
Great bridges being monuments which serve to make known the grandeur and genius of a nation, we cannot pay too much attention to means for perfecting their architecture; this may be varied in treatment, but there must ever be conserved, in form and in decoration, the indispensable character of solidity.

A century ago astronomers, geologists, chemists, physicists, each had an island of his own, separate and distinct from that of every other student of Nature; the whole field of research was then an archipelago of unconnected units. To-day all the provinces of study have risen together to form a continent without either a ferry or a bridge.

A large part of the training of the engineer, civil and military, as far as preparatory studies are concerned; of the builder of every fabric of wood or stone or metal designed to stand upon the earth, or bridge the stream, or resist or float upon the wave; of the surveyor who lays out a building lot in a city, or runs a boundary line between powerful governments across a continent; of the geographer, navigator, hydrographer, and astronomer,—must be derived from the mathematics.

A railroad may have to be carried over a gorge or arroya. Obviously it does not need an Engineer to point out that this may be done by filling the chasm with earth, but only a Bridge Engineer is competent to determine whether it is cheaper to do this or to bridge it, and to design the bridge which will safely and most cheaply serve.

Ask a follower of Bacon what [science] the new philosophy, as it was called in the time of Charles the Second, has effected for mankind, and his answer is ready; “It has lengthened life; it has mitigated pain; it has extinguished diseases; it has increased the fertility of the soil; it has given new securities to the mariner; it has furnished new arms to the warrior; it has spanned great rivers and estuaries with bridges of form unknown to our fathers; it has guided the thunderbolt innocuously from heaven to earth; it has lighted up the night with the splendour of the day; it has extended the range of the human vision; it has multiplied the power of the human muscles; it has accelerated motion; it has annihilated distance; it has facilitated intercourse, correspondence, all friendly offices, all dispatch of business; it has enabled man to descend to the depths of the sea, to soar into the air, to penetrate securely into the noxious recesses of the earth, to traverse the land in cars which whirl along without horses, to cross the ocean in ships which run ten knots an hour against the wind. These are but a part of its fruits, and of its first-fruits; for it is a philosophy which never rests, which has never attained, which is never perfect. Its law is progress. A point which yesterday was invisible is its goal to-day, and will be its starting-point to-morrow.”

Attention makes the genius; all learning, fancy, and science depend on it. Newton traced back his discoveries to its unwearied employment. It builds bridges, opens new worlds, and heals diseases; without it Taste is useless, and the beauties of literature are unobserved; as the rarest flowers bloom in vain, if the eye be not fixed upon the bed.

Bridges would not be safer if only people who knew the proper definition of a real number were allowed to design them.

Chuang Tzu and Hui Tzu were standing on the bridge across the Hao River. Chuang Tzu said, “Look how the minnows are shooting to and fro! How joyful they are!”
“You are not a fish,” said Hui Tzu. “How can you know that the fishes are joyful?”
“You are not I,” answered Chuang Tzu, “How can you know I do not know about the joy of fishes? ... I know it from my own joy of the water.”
An ancient Chinese story

Felling a tree was possibly the original deed of appropriation of the natural earth by early mankind in Europe. Thousands of years ago,… man lifted a heavy flint tool and struck at the base of a tree. He may have wanted the tree for shelter and fuel, or possibly to make a bridge over a river or a path through a bog…. [E]ventually the tree crashed to the floor, and the first act in the slow possession of the land by its people was complete.

From the intensity of the spots near the centre, we can infer that the protein molecules are relatively dense globular bodies, perhaps joined together by valency bridges, but in any event separated by relatively large spaces which contain water. From the intensity of the more distant spots, it can be inferred that the arrangement of atoms inside the protein molecule is also of a perfectly definite kind, although without the periodicities characterising the fibrous proteins. The observations are compatible with oblate spheroidal molecules of diameters about 25 A. and 35 A., arranged in hexagonal screw-axis. ... At this stage, such ideas are merely speculative, but now that a crystalline protein has been made to give X-ray photographs, it is clear that we have the means of checking them and, by examining the structure of all crystalline proteins, arriving at a far more detailed conclusion about protein structure than previous physical or chemical methods have been able to give.

Good composition is like a suspension bridge—each line adds strength and takes none away.

Great triumphs of engineering genius—the locomotive, the truss bridge, the steel rail— ... are rather invention than engineering proper.

His “Mathematical Games” column in Scientific American is one of the few bridges over C.P. Snow’s famous “gulf of mutual incomprehension’' that lies between technical and literary cultures.

I am one of the unpraised, unrewarded millions without whom Statistics would be a bankrupt science. It is we who are born, who marry, who die, in constant ratios. It is we who are born, who marry, who die, in constant ratios; who regularly lose so many umbrellas, post just so many unaddressed letters every year. And there are enthusiasts among us who, without the least thought of their own convenience, allow omnibuses to run over them; or throw themselves month by month, in fixed numbers, from the London bridges.

I have paid special attention to those Properties of the Positive Rays which seem to throw light on the problems of the structure of molecules and atoms and the question of chemical combination … I am convinced that as yet we are only at the beginning of the harvest of results which will elucidate the process of chemical combination, and thus bridge over the most serious gap which now exists between Physics and Chemistry.

i² = j² = k² = ijk = - 1
[This representation was devised on 16th Oct 1843, and which he carved into a stone of Brougham Bridge, over the Royal Canal, Dublin. It has since worn away.]

If the Commission is to enquire into the conditions “to be observed,” it is to be presumed that they will give the result of their enquiries; or, in other words, that they will lay down, or at least suggest, “rules” and “conditions to be (hereafter) observed” in the construction of bridges, or, in other words, embarrass and shackle the progress of improvement to-morrow by recording and registering as law the prejudices or errors of to-day.
[Objecting to any interference by the State with the freedom of civil engineers in the conduct of their professional work.]

In place of science, the Eskimo has only magic to bridge the gap between what he can understand and what is not known. Without magic, his life would be one long panic.

In the pursuit of the physical sciences, the imagination supplies the hypothesis which bridges over the gulf that separates the known from the unknown.

It did not cause anxiety that Maxwell’s equations did not apply to gravitation, since nobody expected to find any link between electricity and gravitation at that particular level. But now physics was faced with an entirely new situation. The same entity, light, was at once a wave and a particle. How could one possibly imagine its proper size and shape? To produce interference it must be spread out, but to bounce off electrons it must be minutely localized. This was a fundamental dilemma, and the stalemate in the wave-photon battle meant that it must remain an enigma to trouble the soul of every true physicist. It was intolerable that light should be two such contradictory things. It was against all the ideals and traditions of science to harbor such an unresolved dualism gnawing at its vital parts. Yet the evidence on either side could not be denied, and much water was to flow beneath the bridges before a way out of the quandary was to be found. The way out came as a result of a brilliant counterattack initiated by the wave theory, but to tell of this now would spoil the whole story. It is well that the reader should appreciate through personal experience the agony of the physicists of the period. They could but make the best of it, and went around with woebegone faces sadly complaining that on Mondays, Wednesdays, and Fridays they must look on light as a wave; on Tuesdays, Thursdays, and Saturdays, as a particle. On Sundays they simply prayed.

It is both a sad and a happy fact of engineering history that disasters have been powerful instruments of change. Designers learn from failure. Industrial society did not invent grand works of engineering, and it was not the first to know design failure. What it did do was develop powerful techniques for learning from the experience of past disasters. It is extremely rare today for an apartment house in North America, Europe, or Japan to fall down. Ancient Rome had large apartment buildings too, but while its public baths, bridges and aqueducts have lasted for two thousand years, its big residential blocks collapsed with appalling regularity. Not one is left in modern Rome, even as ruin.

It seems to me that it had no other rationale than to show that we are not simply the country of entertainers, but also that of engineers and builders called from across the world to build bridges, viaducts, stations and major monuments of modern industry, the Eiffel Tower deserves to be treated with more consideration.

It so happens that the work which is likely to be our most durable monument, and to convey some knowledge of us to the most remote posterity, is a work of bare utility; not a shrine, not a fortress, not a palace, but a bridge.
Writing upon the opening of the Brooklyn Bridge, New York.

It was his [Leibnitz’s] love of method and order, and the conviction that such order and harmony existed in the real world, and that our success in understanding it depended upon the degree and order which we could attain in our own thoughts, that originally was probably nothing more than a habit which by degrees grew into a formal rule. This habit was acquired by early occupation with legal and mathematical questions. We have seen how the theory of combinations and arrangements of elements had a special interest for him. We also saw how mathematical calculations served him as a type and model of clear and orderly reasoning, and how he tried to introduce method and system into logical discussions, by reducing to a small number of terms the multitude of compound notions he had to deal with. This tendency increased in strength, and even in those early years he elaborated the idea of a general arithmetic, with a universal language of symbols, or a characteristic which would be applicable to all reasoning processes, and reduce philosophical investigations to that simplicity and certainty which the use of algebraic symbols had introduced into mathematics.
A mental attitude such as this is always highly favorable for mathematical as well as for philosophical investigations. Wherever progress depends upon precision and clearness of thought, and wherever such can be gained by reducing a variety of investigations to a general method, by bringing a multitude of notions under a common term or symbol, it proves inestimable. It necessarily imports the special qualities of number—viz., their continuity, infinity and infinite divisibility—like mathematical quantities—and destroys the notion that irreconcilable contrasts exist in nature, or gaps which cannot be bridged over. Thus, in his letter to Arnaud, Leibnitz expresses it as his opinion that geometry, or the philosophy of space, forms a step to the philosophy of motion—i.e., of corporeal things—and the philosophy of motion a step to the philosophy of mind.

Museums are, in a way, the cathedrals of the modern world, places where sacred issues are expressed and where people come to reflect on them. A museum is also a kind of bridge between the academy and the public.

Never burn your bridges, especially if you pursue science as a career.

October 9, 1863
Always, however great the height of the balloon, when I have seen the horizon it has roughly appeared to be on the level of the car though of course the dip of the horizon is a very appreciable quantity or the same height as the eye. From this one might infer that, could the earth be seen without a cloud or anything to obscure it, and the boundary line of the plane approximately the same height as the eye, the general appearance would be that of a slight concavity; but I have never seen any part of the surface of the earth other than as a plane.
Towns and cities, when viewed from the balloon are like models in motion. I shall always remember the ascent of 9th October, 1863, when we passed over London about sunset. At the time when we were 7,000 feet high, and directly over London Bridge, the scene around was one that cannot probably be equalled in the world. We were still so low as not to have lost sight of the details of the spectacle which presented itself to our eyes; and with one glance the homes of 3,000,000 people could be seen, and so distinct was the view, that every large building was easily distinguishable. In fact, the whole of London was visible, and some parts most clearly. All round, the suburbs were also very distinct, with their lines of detached villas, imbedded as it were in a mass of shrubs; beyond, the country was like a garden, its fields, well marked, becoming smaller and smaller as the eye wandered farther and farther away.
Again looking down, there was the Thames, throughout its whole length, without the slightest mist, dotted over its winding course with innumerable ships and steamboats, like moving toys. Gravesend was visible, also the mouth of the Thames, and the coast around as far as Norfolk. The southern shore of the mouth of the Thames was not so clear, but the sea beyond was seen for many miles; when at a higher elevation, I looked for the coast of France, but was unable to see it. On looking round, the eye was arrested by the garden-like appearance of the county of Kent, till again London claimed yet more careful attention.
Smoke, thin and blue, was curling from it, and slowly moving away in beautiful curves, from all except one part, south of the Thames, where it was less blue and seemed more dense, till the cause became evident; it was mixed with mist rising from the ground, the southern limit of which was bounded by an even line, doubtless indicating the meeting of the subsoils of gravel and clay. The whole scene was surmounted by a canopy of blue, everywhere free from cloud, except near the horizon, where a band of cumulus and stratus extended all round, forming a fitting boundary to such a glorious view.
As seen from the earth, the sunset this evening was described as fine, the air being clear and the shadows well defined; but, as we rose to view it and its effects, the golden hues increased in intensity; their richness decreased as the distance from the sun increased, both right and left; but still as far as 90º from the sun, rose-coloured clouds extended. The remainder of the circle was completed, for the most part, by pure white cumulus of well-rounded and symmetrical forms.
I have seen London by night. I have crossed it during the day at the height of four miles. I have often admired the splendour of sky scenery, but never have I seen anything which surpassed this spectacle. The roar of the town heard at this elevation was a deep, rich, continuous sound the voice of labour. At four miles above London, all was hushed; no sound reached our ears.

Subtle as the mind is it can effect little without knowledge. It cannot construct a bridge, or a building, or make a canal, or work a problem in algebra, unless it is provided with information.

The bottom line for mathematicians is that the architecture has to be right. In all the mathematics that I did, the essential point was to find the right architecture. It’s like building a bridge. Once the main lines of the structure are right, then the details miraculously fit. The problem is the overall design.

The essence of engineering consists not so much in the mere construction of the spectacular layouts or developments, but in the invention required—the analysis of the problem, the design, the solution by the mind which directs it all.

The first concept of continental drift first came to me as far back as 1910, when considering the map of the world, under the direct impression produced by the congruence of the coast lines on either side of the Atlantic. At first I did not pay attention to the ideas because I regarded it as improbable. In the fall of 1911, I came quite accidentally upon a synoptic report in which I learned for the first time of palaeontological evidence for a former land bridge between Brazil and Africa. As a result I undertook a cursory examination of relevant research in the fields of geology and palaeontology, and this provided immediately such weighty corroboration that a conviction of the fundamental soundness of the idea took root in my mind.

The first drizzling shower is born...
[Then] the flood comes down,
Threatening with deluge this devoted town. ...
Now from all parts the swelling kennels flow,
And bear their trophies with them as they go:
Filth of all hues and odors seem to tell
What street they sailed from, by their sight and smell.
They, as each torrent drives with rapid force,
From Smithfield or St. Pulchre’s shape their course,
And in huge confluence joined at Snow Hill ridge,
Fall from the conduit prone to Holborn Bridge.
Sweepings from butchers’ stalls, dung, guts, and blood.
Drowned puppies, stinking sprats, all drenched in mud,
Dead cats, and turnip tops, come tumbling down the flood.

The Golden Gate Bridge is a giant moving math problem.

The most important object of Civil Engineering is to improve the means of production and of traffic in states, both for external and internal trade. It is applied in the construction and management of roads, bridges, railroads, aqueducts, canals, river navigation, docks and storehouses, for the convenience of internal intercourse and exchange; and in the construction of ports, harbours, moles, breakwaters and lighthouses; and in the navigation by artificial power for the purposes of commerce. It is applied to the protection of property where natural powers are the sources of injury, as by embankments forthe defence of tracts of country from the encroachments of the sea, or the overflowing of rivers; it also directs the means of applying streams and rivers to use, either as powers to work machines, or as supplies for the use of cities and towns, or for irrigation; as well as the means of removing noxious accumulations, as by the drainage of towns and districts to ... secure the public health.

The rainbow, “the bridge of the gods,” proved to be the bridge to our understanding of light—much more important.

The scientific method is only imagination set within bounds. … Facts are bridged by imagination. They are tied together by the thread of speculation. The very essence of science is to reason from the known to the unknown.

The tool which serves as intermediary between theory and practice, between thought and observation, is mathematics; it is mathematics which builds the linking bridges and gives the ever more reliable forms. From this it has come about that our entire contemporary culture, inasmuch as it is based on the intellectual penetration and the exploitation of nature, has its foundations in mathematics. Already Galileo said: one can understand nature only when one has learned the language and the signs in which it speaks to us; but this language is mathematics and these signs are mathematical figures.

There is nothing in machinery, there is nothing in embankments and railways and iron bridges and engineering devices to oblige them to be ugly. Ugliness is the measure of imperfection.

Tiny ferryboats they were, each laden with its little electric charge, unloading their etheric cargo at the opposite electrode and retracing their journeyings, or caught by a cohesive force, building up little bridges, or trees with quaint and beautiful patterns.
Describing the flow of electrons between electrodes in a vacuum tube.

We will build the roads and bridges, the electric grids and digital lines that feed our commerce and bind us together. We'll restore science to its rightful place, and wield technology's wonders to raise health care's quality and lower its cost. We will harness the sun and the winds and the soil to fuel our cars and run our factories. And we will transform our schools and colleges and universities to meet the demands of a new age. All this we can do. All this we will do.

When someone builds a bridge, he uses engineers who have been certified as knowing what they are doing. Yet when someone builds you a software program, he has no similar certification, even though your safety may be just as dependent upon that software working as it is upon the bridge supporting your weight.

Willis Rodney Whitney ... once compared scientific research to a bridge being constructed by a builder who was fascinated by the construction problems involved. Basic research, he suggested, is such a bridge built wherever it strikes the builder's fancy—wherever the construction problems seem to him to be most challenging. Applied research, on the other hand, is a bridge built where people are waiting to get across the river. The challenge to the builder's ingenuity and skill, Whitney pointed out, can be as great in one case as the other.