There is a practical difficulty in combining the great strength, which it is desirable that a snag-boat should possess, with that lightness of draught which is requisite for working at the lowest stages of water, when the most dangerous snags become visible. I believe, however, that we are now in possession of plans that, with the experience which has been gained in the last eighteen months, will enable us to produce the right sort of boat, in case further appropriations should be granted for continuing these western river improvements, which have been so well begun.

Since these boats began to operate, changes have been made in points of minor detail, which have greatly simplified and expedited the process of destroying snags, and at the same time demonstrated, I think, the feasibility of making a lighter-draught boat that will do the work effectually.

To show what is thought of the boats and machinery of our fleet, by engineers of much longer experience on these western rivers than I enjoyed, I beg leave to refer to the special report of Major H. C. Long, United States civil engineer, dated January 20, 1869, and that of Mr. W. Milnor Roberts, United States civil engineer, dated May 13, 1869, copies of both of which reports are herewith submitted, E and F. With such evidence in favor of my operations, I feel that we may confidently expect that appropriations will be granted to provide for continuing these works on a scale adequate to their importance, as set forth in my annual estimates, which I have laid before you to accompany this report.

The following is a recapitulation of the work done by the several snagboats during the fiscal year:

It may be observed, that in reckoning the weight of snags, it was only during the last four months of the fiscal year that the weight of roots was taken into the account. If this had been done from the first, the number of tons would probably have been some 70,000, instead of the 35,758.9, as shown in this table; for it is found that the root, with the earth which it generally brings up with it, much exceeds the rest of the snag in weight.

OPERATIONS FOR PRESENT WORKING SEASON.

It is expected to continue the operations, as now carried on, during the remainder of the present working season, taking the snag-boats and dredge-boat to other parts of the field, as the stage of water and the necessities of the navigation may demand. The dredge-boat will probably be at work upon the bars of the Mississippi, between Keokuk and St. Louis, and perhaps between St. Louis and Cairo, as may be needed.

It is supposed that the demand for her services will probably be greater than she can respond to. In the course of September it is expected that all of the boats will be drawn from the Missouri and employed upon the Mississippi, and as soon as the fall rise may give sufficient water in the Ohio, one of our snag-boats will probably commence to work up that river, from the mouth.

The surveys will be limited to such as may be required preparatory to dredging the bars, and will be executed by the assistants now on board of the dredging-boat.

The Arkansas River surveying party having been reduced to the force necessary for carrying on the office work, will be continued at that until the completion of the maps requisite for exhibiting the results of the survey.

The light-draught snag-boat, S. Thayer, it is expected to continue at work in the Arkansas River. As soon as the cold weather sets in it is expected to send the fleet, now working in the Missouri, to work in the mouth of the Arkansas River, and as far up that stream as the stage of water may then admit of their working. They will also find work in the lower Mississippi, and will be kept at work as long as the funds in hand will justify it. It will probably become necessary to lay them up by the month of March, 1870, unless additional funds for keeping them at their useful and acceptable work shall be granted before that time.

I have introduced this subject into my annual estimates under the head of "Improving the Mississippi, Missouri and Arkansas Rivers," and have asked that the sum of eighty thousand dollars may be appropriated at as early a day as possible to enable us to prosecute these labors uninterruptedly to the end of the current fiscal year. Indeed, the delay incidental to laying up the boats of our working fleet would be a most serious loss, as it would throw the boats out of service just at the time when the work can be most advantageously pushed forward in the Missouri River, the most difficult part of the field. I trust, therefore, that the sum above named may be appropriated in advance of any general appropriation.

Besides the annual estimate, which has already been forwarded, the following papers are referred to in this report, and are forwarded with it: Snag list of the J. J. Abert, for the year ending 30th June, 1869, marked A.

Snag-list of the S. H. Long, for the year ending 30th June, 1869, marked B.

Snag-list of the R. E. De Russy, for the year ending 30th June, 1869, marked C.

Snag-list of the S. Thayer, for the year ending 30th June, 1869, marked D.

Report of United States Civil Engineer H. C. Long, marked E. Report of United States Civil Engineer W. Milnor Roberts, marked F. Report of my assistant, Major C. R. Suter, captain engineers, marked G. Report of my assistant, Mr. S. T. Abert, marked H.

Paper showing amount disbursed on these works in last fiscal year, marked K.

All of which is respectfully submitted by your most obedient servant,
J. N. MACOMB,

Colonel Engineers, Brevet Colonel United States Army,.
General Superintendent United States Snag-boats, and
Western River Improvements.

Bvt. Maj. Gen. A. A. HUMPHREYS,

Brig. Gen. and Chief of Engineers U. S. A.,

Office of Chief of Engineers, Washington, D. C.

N.-Abstract of contracts made on account of the construction of snag-boats and apparatus for clearing western rivers.

M.-Abstract of proposals for the construction of a light-draught, double-hulled snag-boat and tow-boat, complete, designed for the Arkansas River.

NEW YORK, January 20, 1869. GENERAL: I forward herewith a report of H. C. Long, United States civil engineer, on his examination of the boats operating under direction of Colonel J. N. Macomb. I received it January 9, but supposed it was sent me for my information only, as Major Long had been directed to report to Colonel Macomb, and I supposed had made full report to him. On seeing Colonel Macomb in Washington, on the 16th instant, he informed me that no report had been made to him, he having suggested Major Long to make it to me. The irregularity of the proceeding accounts for my having kept it so long. I now transmit it to you as an inspection report made by Major Long, and which, as such, I think, should have been addressed directly to the bureau.

He speaks in terms of high commendation of the new snag-boats built by Colonel Macomb.

Yours, respectfully,

Bvt. Maj. Gen. A. A. HUMPHREYS,

G. K. WARREN,

Major Engineers, &c.

Brigadier General and Chief of Engineers U. S. A.

UNITED STATES ENGINEER OFFICE,

Saint Paul, Minnesota, January 1, 1869. GENERAL: In accordance with the suggestion of Colonel John N. Macomb, Corps of Engineers, general superintendent United States snagboats and western river improvements, dated at Cincinnati, November 10, 1868, that "I should be ordered to report to him for the purpose of a mutual comparison and interchange of opinions and suggestions upon the several subjects of dredging with Long's scraper, and of destroying snags with our improved snag-boats," and approval of the same by the Chief of Engineers and myself, I left Saint Paul for the purpose specified on the 18th of November last.

On the 27th November I received a telegram at Alton, Illinois, from Brevet Major Charles R. Suter, Corps of Engineers, as follows:

To Major H. C. LONG:

Will be at Alton this p. m. on steamer Octavia.

ST. LOUIS, November 27, 1868.

Major Suter arrived at Alton with the Octavia at the appointed time. The next day was devoted to an examination of the Long's scraper, attached to her bows, and a trial of the same on the bar about three-fourths of a mile above the city landing. This bar crosses the river obliquely from the Illinois shore, trending down the river till it nearly reached the dry sand-bar on the Missouri side, and was slightly overlapped by a short bar extending from the latter, forming quite a serious obstruction to the passage of heavily-loaded steamboats. The best water across same was found to have a depth of four and a half feet. At this point the experiments were made with the Octavia scraper. Six successive drags or scrapes were made across the obstruction, occupying about two bours from the time we left the Alton landing till we returned. In that time the depth of water on the bar was increased to six and a half feet, and I have since been informed by pilots, and other river men, that we so cut up and loosened the bottom of the river, that in the course of three or four days afterwards the current washed out a channel ten feet in depth, in the direction and along the trace scooped out by the scraper.

We find that the greater width of the river gives better facilities for maneuvering the scraper than met with above the rapids, and tends to the conviction that the machine will work equally as well in the Lower as in the Upper Mississippi, the frame-work which carries the cutters or buckets, the slides and drag-chains, being proportionately lengthened.

The Octavia, at the time of her visit to Alton, was under charter by government for a limited period; it had not been concluded to purchase her; on this account the scraper was not mounted with a view to permanency, and the lowering and raising of the machine on to and from the bars was accompanied by considerable delay and difficulty. The scraper had but four cutters instead of five, as used in the upper river on those of largest size. Accordingly, it was recommended that certain improvements be made in the apparatus for handling the machine, and that a larger scraper be attached to her bows; after which it is confidently expected that, with proper management, the Octavia will do most efficient service in dredging the bars between Keokuk and Cairo. She is a powerful, well-built steamboat, light draught, commodious, and in all respects admirably well suited for the service intended.

On the 5th of December I joined Major Suter at Cairo. The next day we went to Mound City and inspected the large, double-hulled snagboat De Russy. On the 7th we started from Cairo, with the Octavia, for the Lower Mississippi, for the purpose of observing the operations of the other large twin snag-boats J. J. Abert and S. H. Long. We met the former at Fletcher's Landing, on the evening of the 8th of December, and remained with her that night and till eight o'clock next morning, during which time we went on board and examined thoroughly all the details of her machinery, and witnessed her operations in extracting a dangerous snag from the main channel of the river. This snag was a cottonwood tree ninety feet long, three feet two inches in diameter at butt, tapering to a few inches at the top. The boat was about fifteen minutes raising it from the water and placing it on the rollers be

tween the two hulls, preparatory to its being cut up and otherwise disposed of. This was not considered by any means a fair test of the capacity of the boat, as the snag was not firmly imbedded in the mud at its roots, and was under the average size of snags in this locality. But it served to show the method of maneuvering the boat, handling the machinery, the discipline of the officers and crew, &c., and in these particulars was very satisfactory. On the afternoon of the same day (December 9) we arrived at Memphis, Tennessee, and lay there till 10.30 next day, taking on coal, stores, &c. From this place I reported to you. On the morning of the 11th December we overtook the snag-boat S. H. Long, in Friar's Bend, ten miles below Helena, Arkansas. After inspecting her we turned up the river again, arriving at Memphis on the 12th, meeting and visiting the De Russy on her way down, a few miles above that city. We also made a second visit to the J. J. Abert on the 13th December, near Island 37. At that time she had a snag on her rollers-cottonwood tree-measuring, exclusive of very heavy and widespreading roots, one hundred and thirty feet in length, sixteen feet in circumference at the large end, and eight feet in circumference at the small end. The captain of the boat informed me that it took them three and a half hours to get this snag on to the boat, and that it would take about as much longer to cut it up and put it out of the way, or about seven hours' work in all to dispose of a snag of these dimensions.

In the meanwhile it had turned very cold, the mercury having been as low as +15° at Helena, the morning we were there. We encountered heavy floating ice about two hundred miles below Cairo, and with considerable difficulty reached that city on the evening of December 15.

The next day Major Suter and myself went on the cars to Cincinnati; the Octavia having been sent to Mound City to have the alterations made in the mounting of her scraper, suggested in the former part of this report, and to undergo other slight alterations, the boat having been purchased by government.

On the 17th December we reported to Colonel Macomb, at Cincinnati, and accompanied him and Captain Shields, head machinist, &c., in an inspection of a light-draught machine-boat and small stern-wheel boat for the propulsion of same, building and on the ways in the upper portion of that city. We also visited the foundery and examined castings and machinery in preparation for same boats.

Having thus completed the duties assigned me as per instructions, &c., mentioned in the early part of this report, I returned to St. Louis, &c., &c., and reported to you accordingly.

I take this occasion to express the gratification afforded by the inspection and operations of the large twin snag-boats, J. J. Abert, S. H. Long, and R. E. De Russy. These boats appear to be most substantially built of the best material, and complete in all their appointments, well officered and well disciplined, They are, in many respects, great improvements on the old snag-boats, such as built by Captain H. M. Shreve, Captain John W. Russell, and others, in that the old boats had but one set of engines; these not only propelled the boat, but worked the snagging gearing when disconnected from the paddle-wheels; whereas in the boats built under the direction of Colonel Macomb, the propelling power is distinct from that which works the snagging apparatus; and various other time and labor saving contrivances are introduced, such as steam gearing for sawing up the snags, steam capstans, steam hoist for the drag chains, &c., &c., while, as before said, the old snag-boats had but one pair of engines with which to perform all the work required of them, and drive them from point to point, long dis