It had been said that nearly every invention of man is akin to some part of his own body. Spectacles and microscopes are simply ‘eyes’ which enable him to see more clearly; while telescopes and television make it possible for him to see at great distance. In the same way, telephones and wireless give greater powers to his voice and ears. The pillars, which hold up great buildings, such as cathedrals, are like the limbs, which support man’s body; and bridges, which span wide valleys and great rivers, are like long arms trust out to grasp some other point of shore.

One of man’s earliest problems was how to cross water: as the old song puts it, ‘He came to a river and he couldn’t get across.’ He could, of course, swim, or wade, or even ferry across in a roughly made boat; he might use stepping-stones if the water was not too deep; or he might make a ford by laying flat stones close together in some shallow, level part of the riverbed.

As last, however, man hit on the plan of building a bridge. This might be done very simply, as it is still done in Tibet, by felling a tall straight tree close to the stream’s edge and allowing it to fall across to the opposite bank. Then wooden bridges were built upon supports which rested on the bed of the stream, bridges over which the light traffic of those days could pass with ease and in comfort. Bridge building, as we know it, had begun.

The greatest bridge-builders of olden times were the Romans, for their vast empire made it necessary to move armies rapidly from place to place. At first their bridges, even those in the city of Rome and across the Thames at London, were made of wood; then, since wood was liable to rot or to be washed away in time of flood, they began to build stone bridges. Such bridges were built upon arches, for the Romans were the first people to understand fully the great strength of a stone arch. Some of these Roman bridges still stand proudly in various parts of Europe and North Africa, though they have, of course, been repaired from time to time.


In later times hand some stone bridges we built over most of the great rivers of Europe. Over some of them stood shops and houses as well as a roadway, while the river flowed beneath. The most famous of such bridges was London Bridge, which was built about the year 1200. For six centuries it remained, holding up its quaint load of houses, bookshops and taverns, though it must be confessed that the old song ‘London Bridge is failing down’ was sometimes true, for the bridge collapsed more than once.

In the nineteenth century the great increase in trade, and especially the coming of the railways, made bridge building more important than ever. How fortunate it was that, owing to new methods and discoveries, it now became possible to use iron, and later steel, as a bridge-building material instead of stone! Longer and stronger bridges could now be built.

Engineers had to make many experiments, and sometimes there were curious results. Stephenson, for example, built a railway bridge over the Menai Starits (North Wales) in the form of an iron tunnel or tube, supported upon lofty stone pillars. The bridge-the Britannia Bridge, as it is called-is still in use, but very few have been built on this plan.

Sometimes, too there were failures and disasters. In France, a bridge collapsed while a regiment of soldiers was marching across. The regular marching step of the soldiers caused it to swing so violently that the supports gave way. Many of the soldiers were drowned.


More dreadful still was the end of the first Tay Bridge, the pillars of which are still to be seen alongside the present bridge. The engineer who designed it had not allowed enough for the fierce gales which often blow on his part of the Scottish coast, and on a wild night of storm, in December 1879, part of the bridge fell, carrying with it a train and seventy-three passengers.

Nevertheless, engineers, like all wise people, are glad to learn from failures, and even from disasters. As a result, greater and stronger and ever more wonderful bridges are being built as the years go by.