Prince Kropotkin, of Russia, who has traveled in this country and paid particular attention to the condition of agriculture, says in his summing up: “American agriculture offers an imposing sight; not in the wheat fields of the far West, which will soon become a thing of the past, but by the development of rational agriculture and of the forces which promote it. Read the description of an agricultural exhibition in a small town in Iowa, with 70,000 farmers camping with their families in tents during the fair week, studying, learning, buying and selling, and enjoying life. You see a national fête, and you feel that you deal with a nation in which agriculture is held in respect. Or read the publications of the scores of experiment stations, whose reports are published by thousands and scattered broadcast over the country, and are read by the farmers and discussed at countless farmers’ meetings, and you will feel that American agriculture is a real force, imbued with life, which no longer fears mammoth farms, and needs not, like a child, cry for protection.”
The future of agriculture in this country seems safe, and no class of men can look the future in the face with more of confidence than those who till the soil.
PROGRESS IN CIVIL ENGINEERING
By WALTER LORING WEBB, C.E.,
Assistant Prof. of Civil Engineering, University of Pennsylvania.
I. AN INTRODUCTORY VIEW.
If we broadly define civil engineering as the art of construction, then the birth of the art is as old as the emergence of man from savagery. The savage who hollows out a log of wood in order to construct a canoe has taken the first step in the art of shipbuilding; and when he has constructed a hut, however rude, to take the place, as an abode, of the cave hollowed out by nature, he has moved one step nearer to those triumphs of building construction which satisfy man’s necessities, comforts, and æsthetic desires. From this standpoint civil engineering is as old as the oldest of the arts and sciences. Not only is civil engineering an ancient art, but when the archæologist points to some of the masterpieces of building construction which have been literally hidden from view by the débris of centuries, and describes the old roads which the disintegrating forces of nature, working for centuries, have not been able to destroy, it is natural to assume that in many features the civil engineering of the present day is but a copy of ancient work, or, at least, that there has been comparatively little real progress. It may be claimed that bridges are very old, that canals, lighthouses, and roads antedate the Christian era, and that even the ancient Egyptians knew that the earth is round, and had made a rough computation of its diameter. But it will be shown that even in these cases there has been an enormous advance, not only in the character and magnitude of the work done, but also in another feature of civil engineering which is frequently overlooked, namely, the economy of labor and material. Civil engineering has been defined as the art of doing well with one dollar what any bungler can do somehow with two dollars. This definition, although very loose and one-sided, nevertheless contains a very important truth. If by improved methods a canal or a bridge can be constructed for one half to one third of what it would have cost by older methods, then the world has advanced, in that it may have two or three canals or bridges at the same cost of labor as would have been previously required for the construction of one. When we add to this a vast improvement in quality, an improvement that would have been previously impossible at any cost, the world’s advance is hardly measurable by any standard. It is a well-known fact that many engineering works, justly considered masterpieces at the time of their construction, could now be replaced by a much better structure for a comparatively small part of their original cost. This statement not only applies to very old constructions, but even to some of the great engineering works of the latter half of this century. Some of these reconstructions have actually occurred, as is illustrated in the Victoria tubular bridge at Montreal, or the Roebling suspension bridge at Niagara Falls,—described later. In fact, the progress in civil engineering during the nineteenth century is chiefly made up of the enormous advances which have been made during the latter half of the century. It should not be argued that these recent constructions are cheaper, because “everything is cheaper now.” The general scale of wages has advanced, and the total cost of construction is cheaper, only because improved methods of work have reduced the labor required to produce finished building material from the raw product and to erect that material into a structure. Therefore in considering in detail the construction of the great masterpieces of this century, we should not lose sight of the enormous advance in general methods of work, which has rendered it possible to have all of these structures which so minister to the prosperity of the world, at such a reduced cost in labor.
A complete discussion of the century’s progress in civil engineering would require a treatise on all modern practice as well as a description of nearly all of the great engineering masterpieces in existence, but the limitations of this article utterly preclude the possibility of even a short discussion of all the branches of the science, to say nothing of a detailed description of all of the examples. The following discussion will therefore be confined to those branches in which the advance has been most notable, even to the unscientific reader, the progress being illustrated by brief statements regarding the most typical constructions.
II. BRIDGES.
Not only is there evidence that bridges of the simplest forms have been used from prehistoric times, but the engineering world has been frequently surprised at the discovery, in semi-barbarous lands where there was evidently no scientific knowledge of bridge construction, of a bridge which, in its mechanical analysis, is a rude example of some one of the more complicated types now in use. But these bridges are always small, and are constructed with an utter disregard of that economy of construction which is one of the great triumphs of modern bridge engineering, being uselessly strong in some parts, considering their weakness in others. At the beginning of this century there was not a wrought-iron or steel bridge in existence. Disregarding stone arches for the present, all other bridges were made of wood—with the exception of a few bridges of cast iron, which were constructed during the latter part of the eighteenth century. But cast-iron is unsuitable for pieces requiring tensile strength; it is also difficult to cast very large pieces with any assurance of uniformity. The best existing examples of cast-iron bridges are, therefore, those of the arch type; but these are very heavy in proportion to their real strength, and would now be much more costly than, as well as inferior to, steel bridges of equal strength. Therefore the great advance in bridge work during this century consists in the development of steel bridge construction, and a brief description will be given of a few bridges which represent the chief types.