The apathy of the public has been unintelligent, but not unintelligible, because bridges and roads are so ordinary, so very trite, that we who use them every day do not think of their supreme influence on the nation’s health and safety. They belong to that realm of custom where truths fall asleep in truisms and facts in platitudes. To understand a thing that seems obvious, or “inevitable,” is among the problems that genius alone can solve in a complete way. Dr. Johnson believed that men and women could marry ugliness without being in the least intrepid, because custom would soon teach them not to know the difference between good looks and bad. As custom dulls our minds even in family life, where affection is most watchful, we cannot be surprised that common roads and bridges are too evident to be seen intelligently. Very few persons love a bridge until it is gone, or until it has been put out of action by Napoleon’s “whiff of gunpowder.” Then a victorious army may be brought to a standstill, like Wellington’s, in Spain, when the retreating French blew up an arch of the colossal Roman bridge at Alcántara, so that for some long days the unfordable Tagus might protect their rearguard. It was no easy task to repair the bridge with a netting of ropes that carried planks; and when the British army crossed the gap on this makeshift footway, Wellington knew that the Devil was not the only archfiend in human affairs. [Illustration: PONT VALENTRÉ AT CAHORS IN FRANCE: THE FORTIFIED GATES AND TOWERS. SEE ALSO THE SECOND PICTURE] Yes, believe me, it is worth while to think of the highways and byways. Try to imagine, for instance, what it has cost in suffering and in death to make fit for use all the traffic arteries and veins that nourish and sustain life in the bodies civil of the world. How long would it take to explore the myriads of rambling footpaths? Could this work be done in two hundred years by a thousand Stanleys? How many lives have been lost in making roads through forests and fens and over mountains? in the construction of railways? in the building of bridges? in the slow cutting of canals? The Suez Canal was a long campaign of stricken fields in the war of trade enterprise;[3] and the Panama Canal has reaped lives as quickly as minor battles reap them. If we could see in a form of visual conception all the sacrifice of life that civilizations have offered to progress on the historic landways and waterways, how terrified we should be! Even the hospitals and sick-beds of humanity have not had a more scaring pathos than that which has accompanied the more peaceable enterprises of mankind. [Illustration: A WAR-BRIDGE OF THE XIV CENTURY AT ORTHEZ IN FRANCE]