AND Railroad Specialties The Servis Tie Plate Cold Metal Sawing Machines Car-Door Equipment Q AND C Scott Boiler Feeder Q AND C Pneumatic Oil Feeding and Saving System THE Q AND C COMPANY, 700-709 WESTERN UNION BLDG., 100 B'dway, NEW YORK. 17 Place D'Arms Hill, MONTREAL. CHICAGO. 109 Endicott Arcade, ST PAUL. 537 Mission St., SAN FRANCISCO In the adaptation of the great powers of nature to the use and convenience of man, the civil engineer, if he would increase those adaptations, must devise methods and use materials which were unknown to earlier generations. In our profession conservatism and precedent are perhaps less valued and properly less appreciated than in some others. Still, the law makers who have done most for the good of mankind are generally those who have made radical departures from the principles of the past and the reformers who have done most to help their fellows have been large enough to rise above the narrow bounds of bigoted conservatism; but as the theologian who cuts entirely loose from the past may become a scoffer rather than a reformer, and as the jurist who would break down all existing laws may be the greatest enemy of society, so it is important for the engineer to give the attention they deserve to the materials and the workmanship which have been in continuous use from earlier times. I propose, therefore, to say something about masonry; the building material of antiquity and of the middle ages; the most permanent building material used; the only material which is suitable for monumental works. The materials used in construction may be divided generally into two classes, which, for want of better names, we may term the lower and the higher materials. The lower comprise earth and stone, whether used in the natural conditions in which they are found or in improved conditions into which they are artificially brought. The higher materials comprise metals and tim ber. Between the two classes of materials there are marked differences. The first difference is in perishability. The lower class may be called imperishable; they consist of chemical elements. combined in stable compounds. The presence of oxygen cannot destroy that which is already completely oxidized. Whatever destruction may occur is of a mechanical character; they may be washed, broken or disintegrated, but in every case it is a mechanical action, the materials themselves do not change. By selecting materials adapted to their specific uses and so arranging them that the agencies of mechanical destruction are as far as possible kept away, we can approach more nearly to an everlasting construction than with anything else. On the other hand both timber and metal are perishable. Timber is an organic substance, subject to the most rapid forms of destruction; the natural exposure to the elements will destroy even the most permanent kinds within the limits of a human life, while the duration of the woods available for ordinary construction is but a few years. Timber is exposed to the more quick oxidation known as fire, the most rapid working agency of destruction which we know. Metal is more durable; it oxidizes slowly, unless exposed to active chemical agencies; its life may be measured by decades instead of years, but it must be an object of constant care. On the other hand, both of the higher classes of material have great tensile strength and can sustain the moderate deformations which are considered essential to the safe resistance of tensile strains; they are the only materials which the engineer is willing to use in tension. We have, therefore, four materials used in construction; earth, masonry, timber, metal. The first of these, earth, is that which has been used in the greatest quantities. Its use was the most easily understood. It required in its original working only the simplest appliances. The first earthwork was probably built by a man with no other tools than his sturdy hands with their thick, coarse nails. It is to this day used more than anything else for dams, for levees, for that greatest of modern tools, the railroad embankment, for the most improved form of modern fortifications. Half civilized people used it to build their sacrificial temples and their burial mounds. If we read the stars rightly it is only by the use of enormous earthworks that the inhabitants of a neighboring planet maintain a prosperous existence on their arid world. Masonry is the building material of history. The greatest, and in many respects the finest, specimens of masonry now existing, were built in a time of which we have no records outside of the land in which they are found, while their extreme antiquity shows that masonry had been carried to a high degree of perfection when written history began. It is the material in which the great constructors of old expressed their highest skill It is the material in which the great city of the Mediterranean recorded its conquest of the world. Until the present century it has been the only material of which great works have been made. Next to earth, timber was probably the first material employed in construction. It is the most convenient of all; light, easily worked, strong, it is indispensable for many purposes; it offered ready means of comfort to the primitive man and where it is still abundant and cheap, it is used more than anything else, men generally preferring to take the risk of destruction in return for the convenience and economy which it offers. It has seen its highest development in our country where abundant forests have for the first time existed with modern machinery and tools to work them. The rapid development of North America has been made possible through the abundance and excellence of its timber. With care many of our timber buildings will be preserved for some centuries as historical relics, but sooner or later the wooden buildings of North America will have disappeared as completely as has the earlier timber architecture of India. Metallic construction is new. It was only rendered possible by the advent of cheap metal work. Metal work was always expensive until the introduction of modern power; until the engineer began to manufacture power, the means for producing metals in large quantities did not exist; until metals could be produced in great quantities they were costly. We have as yet but one metal which is available for general construction and that is iron, whether in the cheap form of the cast metal, in the more expensive and purer form of wrought iron, or in the latest development of ingot metal which we call steel, but which is much more nearly pure iron than cast iron is. This material being a metal is oxidizable and to that extent perishable, but it has far greater strength than anything else which can be used in construction. It gives the greatest results for the least expenditure of matter; where compactness and strength are required it is practically the only thing to use; it is pre-eminently the stuff of which tools should be made, whether those tools be in a machine shop or be structures designed for some specific utilitarian purpose, but its uses are practical rather than more, its substitution for masonry, is only justified on economical grounds. Masonry, therefore, the most permanent form of contruction which man can make, the only material suitable for those works which passing beyond the requirement of tools, assume a monumental character and, enduring from one epoch to another, transmit to future ages the actual work of today; masonry respected for its antiquity, admired for its enduring futurity, is the subject of this lecture. I shall not consider the formulæ by which its strength is calculated nor the details of methods by which it is made, but shall simply give a general outline of what it is and review the principles which must be followed to secure good results. Masonry may be broadly defined as any construction formed. of inorganic non-metallic material, in which the parts are so fitted together as to form a single united whole. In this broad sense it includes every variety of brick work, all kinds of stone masonry and all of the monolithic work commonly called concrete. excludes every form of embankment, whether of earth or stone, in which the materials are held in their final position by the friction of pieces on one another, which limits the slopes on which sliding takes place. Masonry, as defined in this broad way, may be divided into four general classes according to the material of which it is made. The first of these is adobe, the unburned brick of the Egyptians and the Aztecs, the usual cheap building material in all arid countries. The second is brick as we understand it, burned till it is harder and more durable than many kinds of stone, while its regular shape makes it an exceptionally convenient material to The third is stone in all its varieties. The last is concrete, an artificial stone. use. Adobe, or unburned brick is nothing but earth of suitable characacter put in a special shape, but the form in which it is worked and the manner in which it is laid up, class it with masonry. Where protected from water it may be very durable, though less so than the other forms of masonry;the oldest church edifice in the United States, constructed in the sixteenth century, is built of adobe. Its manufacture is very simple; a suitable earth mixed with a little chopped straw is moistened and worked by a hoe into a proper degree of plasticity, shaped in a mould and laid in the sun to dry, the common dimensions being about twice those of ordinary bricks, so that an adobe is about eight times as large as a common brick. Adobes are laid up in a sort of mud mortar made of the same earth and the finished wall is usually plastered with the same kind of mud, thus making a solid wall of hard dry unburned clay. This, from time immemorial, has been the common building material of the Egyptians; their temples and pyramids were of stone; their burial places were caves cut in the rocks on the bluffs along the Nile, but their ordinary dwellings were and still are adobe. Adobe is the common, cheap building material of Mexico and a large part of Spanish America, but the Spaniards found it when they came. It is used in both the old and the new worlds in practically the same manner and in both its use goes back to an extreme antiquity. In a suitable climate adobe forms a most excellent building material, the heavy adobe walls, accompanied as often they are by thick roofs of heavy wooden beams covered with the same material, are a great protection from changes of temperature outside. On the hottest summer day in countries where the outside temperature is often above blood heat the interior of an adobe building is always comfortable and cool. Of all forms of masonry perhaps brick is the most useful. It is in too common use to require description. The bricks should be made of good material and well burned; two kinds of material are used, the ordinary plastic clay which must simply be tempered with water, with perhaps the addition of a little sand, and worked into proper condition, and the various soft slates more properly called shales, which must be ground before they are used; building brick |