the pipe is less than one meter, and this is the case with all these wood Mr. Merriman. pipes. According to Bazin's formula, e should be independent of H. It is clear that the influence of Hupon e will be much less than that of D. The writer has made several attempts to deduce a formula for e in terms of H and D, from the author's data, but they have not been sufficiently successful to record here. Probably the different degrees of roughness of the pipes obscure the influence of the different heads. For the present and immediate future the values of e deduced by the author in his interesting and valuable paper must be used for wood pipes, but the present discussion indicates that the probable value of the quantity, b, may advantageously be computed from

b= 0.009 e2 DH.

Mr. Dillman.

AMERICAN SOCIETY OF CIVIL ENGINEERS.

INSTITUTED 1852.

PAPERS AND DISCUSSIONS.

This Society is not responsible, as a body, for the facts and opinions advanced in any of its publications.

A PROPOSED NEW TYPE OF MASONRY DAM.

Discussion.*

By GEORGE L. DILLMAN, M. Am. Soc. C. E.

GEORGE L. DILLMAN, M. Am. Soc. C. E. (by letter).-Discussion has developed the following criticisms:

1st. The muss is not sufficient.-Mr. Parsons says that this is on account of stability against sliding and overturning; Mr. Abbott says it is on account of difficulties in making the dam tight.

According to the generally accepted laws of friction (which are wrong, but which need not be discussed here), any decrease in mass decreases the factor against sliding, but it is distinctly against elementary engineering to say of stability against overturning: "The important factor is to have mass, rather than little mass mathematically placed." If mass alone is to be considered, what difference does the shape make? The standard types" might be built upside down.

Tightness is considered further on.

2d. The stresses are not determinable.—The stresses may not be measurable, but they are more nearly determinable than stresses in a uniform-sectioned dam, because the point where the water is cut off is more nearly known.

The internal stresses caused by the setting of the concrete masonry are probably not different from a uniform-sectioned dam. Were these large enough for danger, it is certain that each buttress would have to stand for itself, as the thin part of the wall would transmit no large strain to the next buttress.

*Continued from September, 1902, Proceedings. See April, 1902. Proceedings for paper on this subject by George L. Dillman, M. Am. Soc. C. E.

As for external forces, weight will act through the center of gravity Mr. Dillman. more certainly than in a dam in which water penetration is unknown. The same can be said of the center and direction of water pressure. It should be noted that the unit can be considered from center to center of arches as well as from center to center of buttresses.

3d. The plan is difficult to execute and expensive to build. This criticism is made most frequently by those who speak of a cut-stone face. The writer has no idea of using cut stone or even coursed masonry in a dam, except for coping and trimming. Rubble and concrete are the materials for such work to-day. Even rubble is getting to be inexpedient, except to save cement when the haul is expensive.

The curved surface can be developed into a plane, so that either the frames or the lagging of the forms can be straight lumber. For dams of considerable size, frames should probably be up and down, and the lagging bent to these straight frames. For lower dams, when the curvature is sharper, probably horizontal frames with up and down lagging might be better. In either case, the cost is not excessive, and the parabolic is as cheap as any other curved form.

The writer is engaged now in putting in some concrete dam work in which he is using cylindrical, truncated-conical, elliptical and parabolic forms, and, except for a few minutes with his carpenter foreman on each new shape, cannot see that there is any trouble, or much difference in cost between them and straight forms. There is no more lumber used than would be used in a broken surface approximating the curve. The cost of band-sawing the frames is insignificant, and a yard of concrete is rammed against a curved form as cheaply as against a straight one.

4th. A thin wall cannot be made tight.—Mr. Fuller has replied to this criticism by saying: "It would probably be easier to make the thin wall tight than the thick one. That has also been the writer's experience.

There is another consideration: If a dam cannot be made tight at its up-stream face, it is a mistake to tighten it at all. The up-stream face, if not tight, should be the most nearly tight surface. All water passing it should be allowed to escape without exerting further pressure. The penetration of water to some tighter surface is the principal source of doubt in dam stresses. Such penetration practically shifts the center of gravity and the direction of water pressure.

5th. It is not the most economical of its class.-No such claim was made; but the Ogden Dam, with a steel face anchored to bed-rock or massive concrete to stand tension, is hardly in the same class. Economy is not the best point in the proposed type. Increased factors of safety, and chance for inspection and repair are of much more importance.

The dimensions, batters, curves, specific gravity of the masonry, and the allowable strain used, were adopted for purposes of fair com

Mr. Dillman. parison, simplicity and the avoidance of certain criticisms. The general type of buttressed wall can be cheapened materially beyond the particular one analyzed.

6th. It is not new.-It seems to the writer that finding out what has been done, and, therefore, with certainty what can be done, is fully as important to successful engineering as new discoveries. Besides, it was absolutely new to the writer when, in the prosecution of work, he discovered it. It seemed new to some of his friends to whom he showed it. It could not have been "readily found elsewhere," or the Publication Committee of the Society would not have published it.

MEMOIRS OF DECEASED MEMBERS.

NOTE.-Memoirs will be reproduced in the Volumes of Transactions. Any informa tion which will amplify the records as here printed, or correct any errors, should be forwarded to the Secretary prior to the final publication.

MILTON GROSVENOR HOWE, M. Am. Soc. C. E.*

DIED JUNE 19TH, 1902.

Milton Grosvenor Howe was born at Methuen, Massachusetts, on August 16th, 1834.

He was graduated from Dartmouth College in 1854, having taken both the academic and scientific courses. His first work was on a survey for a road which was projected to run north from Saratoga, New York, through the Adirondacks to Sackett's Harbor. The surveying party, in charge of the late John Newell, M. Am. Soc. C. E., spent a winter in the mountains, but the road was never built.

In 1855 Mr. Howe went to Illinois, and was employed on the Illinois Central Railroad until the panic of 1857 caused the stoppage of all construction. His next work was in Iowa, but the stringency in the money market made business dull, and he found himself at the beginning of winter without occupation. Having a fondness for study, he decided to put in the time reading law, and so rapidly did he acquire knowledge that in the spring he passed the examinations and was given a license to practice. He was devoted to engineering, however, and, believing that greater opportunities existed in the Southwest, besides desiring a warmer climate, he went to Texas in the fall of 1859, and entered the service of the Houston and Texas Central Railroad.

At the beginning of the war he enlisted in the Army of the Confederacy as a volunteer in Company A of the Twenty-sixth Texas Cavalry, De Bray's Regiment. Within a year he was transferred to the Engineering Corps and given the rank of Captain. He was an ardent exponent of the cause of the South, and it was by his skill as an engineer and inventor that two of the five cannon used so effectively in the battle of Sabine Pass were improvised.

At the close of the war Captain Howe again entered the service of the Houston and Texas Central Railroad, and held the positions of Chief Engineer, General Superintendent and Division Superintendent.

In 1885 he was made Receiver of the Houston, East and West Texas Railroad. After this road, under his able management, had passed from under the Receivership, he became Vice-President and General

* Memoir prepared by the Secretary from information furnished by Mrs. M. G. Howe.