Progress in Engineering Materials-R. W. Crum. 153 Frontispiece 154 Generation and Consumption of Electric Current in Iowa-H. W. Wagner.. 155 Day Labor vs. Contract System of Road Building— .166 Surface Oiling of City Streets-T. R. Agg. 173 The New Concrete Bleachers at Iowa State College- 185 STUDENTS OF THE DIVISION OF ENGINEERING IOWA STATE COLLEGE, AMES, IOWA Annual subsription $1.00 Single Copies, 15 cents Progress in Engineering Materials O MOST people the work of the ordinary engineer seems prosaic enough, and surely one would not expect to find much of absorbing interest in the very common materials with which the engineer works. Cement and iron and gravel do not seem inspiring, but, never-the-less, to some of the best engineers of the country the study of properties and uses of these materials has been the most fascinating study of all. Their work has brought "Science" to the aid of "Practice" in utilizing the forces of Nature. Through the patient, scientific, but unspectacular researches of a relatively few men, our knowledge concerning the materials with which we must build has been brought to a high degree of accuracy. The pressure of modern industrial conditions requires that we build the best structures at the lowest cost, and to this end an exhaustive study of all phases of construction work has been made imperative. In no other department has better work been done in recent years than in that of the construction materials. The final presentation of the results of the work of investigators along these lines has usually been made in the "Standard Specifications" of the American Society for Testing Materials. This Society has the reputation of being the most active of the national engineering societies, and few will dispute the statement that the publications of this Society are among the most valuable technical papers in the world. Much has been accomplished, but that which is new today is old tomorrow, and new problems are constantly presented. Iowa State College is helping in this important work. The laboratories of the Engineering Department and of the Engineering Experiment Station have many interesting problems under investigation. Some of the more important studies are these: "Reinforced Concrete Drain Tile," by the Drainage Section; "Prepared Roofing Materials," by the Chemical Section; "Iowa Pavements and Paving Materials," by the Good Roads Section; "Iowa Fire Clays," by the Ceramics Section; "The Effects of Various Mixtures and Proportions on the Strength of Gravel Concrete," by the Structural Materials Section. The services of the College laboratories and experts are at the disposal of the people of Iowa, both for routine tests of structural materials and for investigation of problems of industrial and technical interest. R. W. CRUM. This shows how an oiled street looks after several days of rain. Note that only a small amount of mud has resulted. This street is well rounded up, which is essential for proper drainage, There are approximately 230 central stations in Iowa, which generate electric current and which have a combined rating of about 60,000 kilowatts. Generators in these stations are driven by engines, turbines and water wheels, having a combined rating of at least 85,000 horse power. In addition to the generating stations, there are nearly 70 substations located in as many towns and cities. In all, some 300 towns and cities are served and nearly 50% of the population of the state have electric current at hand for light, power, cooking, heating and other purposes. Nearly 25 million dollars are invested in the industry of manufacturing and delivering current to consumers. During 1914, about 75 million kilowatt hours were generated. Perhaps 20% of this energy was lost between the generator and *Electrical Engineer, Engineering Experiment Station, Ames, Iowa. consumer, making 60 million kilowatt hours delivered. At a composite rate of 81/2c, the total gross income was over 5 million dollars. All of the above statements are merely estimates in round figures, and do not take into account the 150,000 horse power hydro-electric plant at Keokuk. They are only approximately accurate because the industry is growing and developing so rapidly that a census taken one year is hopelessly out of date for conditions existing two or three years later. These preliminary estimates are given as a foundation of better understanding of what may follow. According to the 1912 census, Iowa stood as follows among other states of the union: 8th in number of central stations, 24th in kilowatt rating of generators, and 29th in energy output. The large number of comparatively small stations in Iowa is explained by the correspondingly large number of smail towns and cities. When the Keokuk station is included only about eight other states lead in the total kilowatt capacity. During the past few years the Iowa Engineering Experiment Station has been making tests and general investigations and has been publishing results calculated to aid both municipalities and electric companies engaged in the central station industry. The Technical Service Bureau and the Engineering Extension Department, both centered at Ames, are now joining forces with the station in order to make a wider and more definitely applied use of data secured and of technical information available. The most recent investigations pertaining to the electrical industry carried on by the Experiment Station have been in co-operation with the Iowa section of the National Electric Light Association. Prof. F. A. Fish, electrical engineer for the station, is a member of the Facts and Factors committee of the Iowa section. Under his direction many statistics were collected from central stations in the state by visits and correspondence during the past year. The Facts and Factors report was presented at the electrical convention in April and was published in some of the electrical journals soon after. This report as now revised in |