by the student council.

Sec. 2.-Privileges. Membership in the society entitled the holder to all the privileges, including subscription to the Iowa Engineer.

The points of difference between this and the last constitution are these: The office of secretary was formerly combined with that of treasurer. The new constitution provides for a separate secretary. The new constitution also provides that the assistant editor and the assistant business manager of the Iowa Engineer be elected to serve as such during their junior year and at the close of their junior year become automatically the editor and business manager, respectively, of the paper. Until now the position of assistant editor and assistant busines manager have been filled by appointment by the editor and business manager. The new system aught to provide men better qualified for these offices than formerly, for a years' training and familiarity with their duties will be of immense assistance.

The spring election of the society was held on Thursday, March 28, and the following men were elected:

President of the Society-W. D. Hardaway.

Vice-president-Ed Roddewig.

Secretary-Karl J. Schmidt.

Treasurer-R. F. Snyder.

Editor-in-Chief of the Iowa Engineer-F. B. Flick.

Business Manager Don McKee.

Assistant Editor-E. R. McKee.

Assistant Business Manager-C. C. Crawford.

Experiments on Combustion

The Bureau of Mines, Department of the Interior, after several years of experiments in fuel combustion in a special furnace, makes the announcement that from the results it is possible to design a furnace with considerable more assurance as to its capabilities than has heretofore been possible.

Starting with the analysis of the coal to be used and the rate at which it is to be burned, the furnace dimensions in feet and inches can be designed with a reasonable assurance of obtaining a desired degree of completeness of combustion.

The bureau has just made a report on this subject, Bulletin 135, "Combustion of Coal and Design of Furnaces," by Henry Kresinger, C. E. Augustine and F. K. Ovitz. The publication marks a period in work approved in 1906 by a national advisory board appointed by the president to advise the government concerning fuels. The bureau proposed to conduct such experiments as would make it possible to design fuel-burning furnaces on a rational basis rather than by the cut and try methods of the past. The process carried on in the combustion space is infiuenced by many factors, the most important of which are the volume and shape of the combustion space; the kind of coal used, especially the character and amount of volatile matter it contains; the rate of firing; the quantity of air supplied over the fuel bed; the rate of mixing the air with the combustible arising from the fuel bed; the rate of heating the coal, and the temperature in the combustion space.

The qualitative effects on the rate and completeness of combustion of many of these factors have been known for a long time, but the quantitative data, presented in definite units, of seconds, pounds, feet or percentages, have been lacking. To obtain such definite information a study of combustion in the space beyond the fuel bed was undertaken, and the results of extensive tests were conducted in a special furnace using three kinds of coal-Pocahontas, Pittsburg and Illinois-and at rates of ocmbustion covering the full range found in practice. These are believed to be the most extensive tests of the kind ever undertaken.

While the bulletin is especially for those interested in the de sign or reconstruction of fuel-burning furnaces, it contains much of interest to the general engineer interested in fuel problems. Some of the statements sure to arrest the attention of th interested engineer are as follows:

The size of he combustion space required appears to be directly proportional to the percentage of oxygen in the moisture-free and ash-free coal.

The percentage of excess air that gives the best results varies with the size of the furnace and the kind of fuel. This fact explains why in one plant the highest efficiency may be obtained with 14 per cent of CO2 in the gases, and in another plant with only 10 per cent of CO2.

2

There is a definite relation for each coal between the excess air supply and the percentage of CO2 in the furnace gases.

2

Soot is formed at the surface of the fuel bed by heating the hydrocarbons in absence of air. It is not formed by the hydrocarbon gases striking the cooling surfaces of the boiler. As a matter of fact, only a very small trace of the hydrocarbon gases ever reach the surface of the boiler. Hydrocarbons that do so are prevented from decomposition by the cooling effect of the contact. The cooling surfaces do not cause the formation of soot; they merely collect soot and prevent its combustion.

It seems that most mechanical stokers are smokeless not because they burn the smoke, but because they burn the coal in such a way that very little soot or smoke is produced. Handfired furnaces are smoky because soot is produced in or near the fuel bed, and cannot be burned in the limited combustion space of the furnace.

Blaugas---A New Fuel

By WILLIAM KUNERTH*

A comparatively new fuel, known as Blaugas, has recently attracted some attention. It is made by the destructive distillation of petroleum oil. By special processes the poisonous and the explosive ingredients contained in other distilltaes of petroleum oil are removed in the act of manufacture, and thus there is produced a gas which is safe to handle and use.

After its manufacture it is brought into the liquid state by the application of an enormous pressure. It is then ready for distribution among customers. It is shipped in steel containers, each one having a capactiy of twenty pounds or about one cubic foot. This amounts to about 250 cubic feet of expanded gas. When a container has been exhausted, another one is put into its place and the former is shipped back to the factory to be refilled. The cylnders are attached by means of a reducing valve to a small expansion tank, and from these the gas is conducted into the pipe line by a pressure regulator.

The complete apparatus installed where the Balugas is used

*Professor of Illuminating Engineering, Iowa State College.

is small and unassuming. The building has to be piped exactly as for city gas. It is used for heating, lighting and power. It has a heat value of 1800 B. T. U. per cubic foot and it burns like ordinary city gas, but is much richer. When used with a mantle for lighting it gives a soft white light of about 100 c. p., which cannot easily be distingushed from illuminating gas. Small sized engines are being made in which this gas is used as a source of power.

The expense, after the plant has once been installed, is said to be no higher than for city gas. In this case the patron has the added advantage of independence, for he has the plant right on his own premises.

This gas has been used in this state only during very recent years, mainly as a fuel for cooking and lighting. Besides being used for farm homes and village communities, it is used in several of the schools and colleges over the state, and in some places is now a close competitor with city gas. It has a very promising future.

The Blaugas system has recently been installed in the laboratory of the Physics Department at the Iowa State College. It will be used mainly for demonstration and experimental purposes in the course in General Physics and in Illuminating. This system of lighting forms a valuable addition to the many other lightng systems and illumination accessories already installed in the department.

Woman Architect for Housing Project

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A woman is architect of the Bridgeport (Conn.) Housing Project for Munitions Workers. She is Miss Marcia Mead, of 105 West Fortieth Street, New York City. "The project has received the indorsement of the Housing Committee of the Council of National Defense," says the District of Columbia division of the Council, "and will be used in connecton with plans for housing the great number of officers and clerks who are coming to Washington."

Published Monthly During the College Year by the Students of the Division of Engineering, Iowa State College, Ames, Iowa.

Entered as second class matter March 11, 1911, at the postoffice at Ames, Iowa, under the Act of March 3, 1879.

Editorials

With this issue the Iowa Engineer passes out of the hands of the present management into the guidance of the men selected at the recent election to pilot the paper through the year 1918-19. We are sorry to have to leave the work at this point, but the speeding up program has brought our course nearly to a close, and we expect to be inactive after April 19. Consequently the April and May numbers of this paper will have to be handled by the newly elected men.

We wish to say before taking leave of our readers that we believe that the management of the paper will be in excellent hands next year. The two men who will be in charge are both well qualified to make a success of it. We wish them all the luck in the world and commend them to you for your sincere support and co-operation.