difference, there is, of course, no question as to the desirability of exercising a certain amount of supervision over the eligibles or reserve officers. Just what the nature of this supervision should be, and just how far it would be practicable to extend it, are matters of detail which would require considerable thought to determine in the beginning, and which in the end would have to be greatly modified by experience.

On the whole, it would seem that although the plan proposed is perhaps better than the one now followed, the difference is not so great but that the probable results of the former may be judged by the actual results of the latter. The War Department plan has now been in operation for several years, long enough, doubtless, to afford some evidence as to its eventual success, but, so far, I have seen no statement as to whether the results of its trial are considered as demonstrating its effectiveness or not.

It seems to me that the possibility of organizing efficient technical troops as a part of the national guard is passed over a little too lightly. It may be true that the present organizations of technical troops in the national guard leave much to be desired, but, whether it is true or not, it by no means follows that a system can not be devised under which efficient organizations of this kind may be obtained. The proper presentation of such a plan would, however, require too much space to be attempted here, nor would such a plan, even if successful, entirely meet the requirements of the case, since a great number of officers of technical training would still have to be secured after the national guard had been wholly called into service.

Mr. PERCY H. THOMAS

Consulting Electrical Engineer

In considering Mr. Haskins' address one is impressed with the great number of possible plans which might be followed to obtain a technical reserve, but which undoubtedly would nearly all fail to produce the desired results.

What would appear to be the most satisfactory solution, from the point of view of the Army, would be the securing of a sufficiently numerous number of actual reserve engineers, entirely familiar with the Army's organization, discipline, and with the methods and apparatus used in the various engineering services the Army is called upon to do. In the absence of an adequate number of such men, however, much benefit might be obtained from a less immediately available and more broadly founded reserve. Before entering upon his analysis of the reserve phase of the question, Mr. Haskins has made an appeal for closer cooperation between the Army engineers and the civil life engineers. Could not a great deal be acomplished in this direction by the membership of engineer officers in the various professional technical so

cieties, and by the active participation in the way of the presenting of papers and discussions in the proceedings of these societies, so that the questions confronting the Army engineers may become familiar to the membership in general? It is even possible that in such a society as the American Institute of Electrical Engineers, having an organization in which certain sub-committees are appointed to represent various phases of electrical activity, such a sub-committee on army and navy affairs might be appointed. Probably, further, lectures by Army engineers before technical colleges would be very welcome, and would help to attract attention to and forward the interest in military engineering affairs on the part of the undergraduates.

Considering the subject of providing available recruits for the Engineer Corps from a broader point of view, would not the following plan have desirable characteristics? Let the Government or the Army, as may be best, establish at suitable points a number of technical schools whose avowed object should be the education and training of civilian engineers, in competition with the present technical institutions. It is assumed that at the same time a certain amount of special military instruction would be given, and very likely it would be of advantage for the final year's training to consist of practical observation and participation in Government engineering work at the various army posts or stations, as far as practicable, where such work might be in progress. A suitable degree could be offered for satisfactory completion of such a course and, presumably, a reasonable tuition fee required.

From the point of view of the Government, advantage would thus accrue from the existence of a large number of engineers having an elementary training in military affairs, with some knowledge of its problems and organization, and from a working touch on the part of the Government officials with a large number of persons forming approximately the best sort of semi-trained material.

The success of such a plan would, of course, depend upon the preference of a considerable number of young men for such a Government training for their professional work over the present technical schools. I am inclined to think that these schools would be found very attractive. In the first place, because considerable prestige comes with training under the Government, and, secondly, because of the now firmly and widely recognized advantages of the semi-military discipline and physical and moral training such as could be readily obtained. No such standard as is maintained at West Point or the Naval Academy at Annapolis could, of course, be expected, nor would this be necessary. Furthermore, in my opinion, graduates of such Government schools would be preferred to graduates of most of our present technical schools by manufacturing companies and others who absorb the great majority of our technical graduates, on account of the thoroughness of training

in fundamentals, the self-reliance and breadth of view that would be expected in such men.

Presumably, a great premium would be placed by the Army on the younger men, who have more enthusiasm and patriotism, as well as more physical vigor; these are obviously the ones that would be secured by such a Government school system.

There would thus be obtained in a manner perhaps more suitable to American institutions some of the benefit obtained by European nations from the limited period of army service exacted by the government from all men.

Possibly, this plan would not provide enough men having a practical working knowledge of mechanics, etc., as distinguished from a theoretical book knowledge thereof; in which case, possibly, an institution more of the nature of a trade school might be preferable.

Of course, no such set of men as would be turned out by such institutions would wholly take the place of a progressive reserve already enlisted and constantly kept familiar with the progress of the military art.

From another point of view the scheme of Government training schools here very briefly and imperfectly outlined, is much broader and more fundamental than the providing for a technical reserve; it might be considered as a part of the country's general educational system. The necessity for the effective technical training of a larger portion of our workers is well recognized, and the results of Germany's advanced methods of education are conspicuous. While we always need the privately controlled and managed technical institutions, these have, with a few exceptions, great limitations in their small size, insufficient facilites, and inability to pay a teaching staff of the best grade. Government schools would have a great advantage in these directions and would probably be prevented from becoming too conservative by the necessity for active competition with the private institutions. While it may truly be said that many sorts of enterprises are more satisfactorily carried out in private hands than by Government control, this principle has little or no weight in educational matters.

There are, doubtless, many objections that can be urged against Government technical schools for civilian engineers, but perhaps a free discussion might show ways of avoiding them, and the idea. surely has a number of features which strongly recommend it.

ROCK DREDGING AT CARR SHOAL, OCONEE

RIVER, GEORGIA

BY

Mr. H. L. ROBERTS

Carr Shoal, Oconee River, Ga., was in the past the most difficult and dangerous place to navigate on the system of rivers. It was not navigable at all on less than a 1 foot stage of river, and then only for very light-draft boats equipped with windlasses.

When work was first started at Carr Shoal the Katie C, a sternwheel steamer of 100-foot length, 20-foot beam, and drawing 16 inches of water, came up to the shoal, bound up the river for a load of freight. As we had our breast and quarter lines across the old cut we were compelled to discontinue work until she passed and, to save time, decided to pull her through with our steam. We parted all her lines, one after the other, and finally got her through on our 5-inch steel wire rope. This last line had about all the strain on it that it would stand while she was passing the worst places. She was, of course, working her engines full speed ahead all the time. It took three hours to get her through the old cut and we saved an hour or two by helping her. Stage of river, 1.1 foot. This same boat has since passed up through the new cut through the dredged channel in two and three-fourth minutes. Stage of river, 0.5 foot.

The Sapelo started work on the new cut on the 9th day of August and finished on the 14th day of December, being four months and six days on the job.

The only serious difficulty encountered was due to lack of sufficient depth of water to float the pile driver used for drilling over the rock that was to be blasted. On account of this, it was necessary to do a great deal of preliminary work blasting by hand and, in some instances, the steam drill was carried out on the rocks ahead of the plant and a line of steam pipe and hose run to it. A considerable quantity of rock was also taken out by hand, loaded on a small barge and moved to one side. After this blasting had been done by hand, the Sapelo would clean off ahead of her as far as the bucket would reach (about 20 feet) and would then haul back and the pile driver would get in position and blast to depth. This in turn was dredged to depth and the operation

repeated. It is estimated that this preliminary work occupied about one-third of the working time. It was not feasible to blast very far ahead of the digging, as the material would settle back and make dredging very difficult.

The figures at the end show the amount of work done and the cost. Fig. 2 shows the position of the new cut where spoil was placed; soundings and velocity of current taken after completion.

A description of the plant and methods employed may be of interest. The Sapelo, built at Hollingsworth Ferry in 1903, is 85 feet long, 30-foot beam, and draws 30 inches of water. She has a stiff-leg" derrick, using a Lidgerwood No. 4 swinging gear and bull wheel. The boom is 56 feet long and the bucket swings in a circle, the diameter of which is 75 feet. The bucket is a four-blade Haywood orange-peel, of 21 cubic feet capacity. The machinery will stand a speed of 75 swings an hour on a continuous run. This speed can not be attained, however, unless the rock is very well broken up. Much better time can be made on material such

as sand or soft clay.

The swinging engine is a Lidgerwood Standard, double-friction drum engine, of 30 horsepower, and is in good condition. The after engine, used for stern and quarter lines, is a Lidgerwood reversible, double friction, drum engine, which has been in use a long time, but is in serviceable condition. Steam is furnished by an upright tubular boiler of ample capacity.

Drilling was done by two methods. On anything but the very hardest rock, the drills used consisted of a length of octagon steel working in a casing of 11⁄2-inch pipe. The drill in general use was of 11-inch steel with a 4-inch taper point. This was slipped inside the 1%-inch pipe used as a casing, the lower end of the pipe being drawn down to 1% inches to fit snugly around the drill and then sharpened to a cutting edge. The upper end of the drill had an iron collar 1 inch thick by 4 inches square around it, the collar being held in place by upsetting above and below it. The drill extended about 1 inch above the collar. The drill and casing were driven together through rock to the required depth by an 1800-pound hammer working in the leads of the pile driver. A platform hanging from the leads in front provided a place for the men to stand while drilling and loading. Having been driven, the drill was taken out, leaving the casing in the rock. Dynamite was then loaded into the casing, a ramrod held on top of it and the casing was pulled up with the pile fall leading to the top drum of the engine, leaving the powder in the hole. These holes