scows I had engaged, and placed them in position over and inclosing the rock and made a partial survey that was completed on Monday following. Mr. Townsend, the submarine diver, examined the rock, with his armor on, Monday morning whilst I was taking soundings. I estimate that forty-five cubic yards blasted from the ledge will give the same depth of water as is found at other points of the channel between the piers-nine feet at low water.

I am, general, very respectfully,

G. L. GILLESPIE,

Captain of Engineers, Bvt. Lieut. Col. U. S. A.

Bvt. Maj. Gen. J. G. FOSTER, U. S. A.,

Lieutenant Colonel of Engineers.

I have forgotten to mention that near the custom-house wharf, a few rocks called the "Boilers" show themselves at low water; they are dangerous, but lie so near in-shore that but few vessels ever strike them. G. L. G.

APPENDIX T.

BOSTON, MASS., August 18, 1869. GENERAL: I have the honor to make the following report of operations on the sea walls of Great Brewster Island for the year ending June 30, 1869.

In my last annual report (of August 22, 1868) I reported the completion of all the main sea walls, as far as required for the protection of the south head, as also that the main wall itself was built, as far as had been designed, for the protection of the north head of this island. Although, from the increase of cost of work by contract over the estimate by hired labor, the funds had not sufficed to back with earth the last five hundred and fifty feet of this wall, or to set the rough "shells" stone paving in rear, as required for nearly the entire length of this wall.

For the completion of these portions of the work, I was advised, in September, that the estimated funds, $10,000, would be allotted, and the work was at once commenced and pushed as vigorously as possible through the remainder of the season, of which there then remained but some six or eight weeks of good working weather, and, during the autumn, the heavy rear paving on the main exposed easterly face was placed, for some fifteen feet back of this wall, upon one or two feet of small boulders or "shingle" for about seven hundred linear feet, completing the protec tion required for the most exposed part of the wall. The earth backing required has been filled in on the north short face of about one hundred and fifty feet, and on the next adjacent face of two hundred and fifty running feet at the northwest, and it was for the most part completed for the next and last face (of one hundred and fifty running feet) of the wall, and for nearly the whole distance around, some eight hundred running feet, from the termination of the heavy "shells" paving nearly to the face last named; a covering of small cobble stones or boulders was placed to afford a temporary protection from the dash of the sea, until the more reliable, heavy "shells" or large boulder paving (as at Lovell's Island) can be placed.

A good jetty of upright split stone, six to eight feet in height and about six to eight feet in breadth, and extending out obliquely about thirty feet from the west end of the wall of the south face of the south head, was also built; the jetty being sunk one-half its depth in the blue

clay, and surrounded at the base with concrete of two and one-half to three feet in height and width. This appears to secure, effectually, the extremity of the wall from that of the eddying sea.

A dry wall, of three courses of stone on hand, was laid to give a temporary protection to the gap between the north and south head walls. From the lateness of the season at which the funds were available and the early setting in of the winter, it was impossible to finally complete the work required for the rear of the north head wall, although the funds allowed, if used in the more favorable weather of the midsummer, would have sufficed for this purpose. And though some, nearly onefourth, remained on hand, it was not deemed advisable to commence work there this season until a decision was had as to my estimates for $25,000 for constructing a wall (of two hundred and fifty running feet) between the two walls already built. That sum having been allotted in June, the quarrying and dressing and delivery of the stone facing required (having been previously arranged for conditionally) was at once ordered, and now, at this date, within the past ten days, some three cargoes have been delivered and the work for closing this gap has been vigorously commenced, and it is expected that this wall, with all the work remaining to completely protect the north head, with two or three jetties at the angles-in fact, all that now appears to me to be necessary for the protection of the island-will be completed by the close of the working season, and no further funds are at present thought necessary.

The work of the fiscal year (executed last autumn) comprised the setting of the heavy "shells" stone paving in rear for about seven hundred running feet, including the whole of the main most exposed portion of the east face of the north head, the filling in rear with earth of about four hundred running feet, from the northeast angle to the west and northwest parts, and the placing of the greater part of this earth filling at the back of the last northwest face, (of about one hundred and fifty running feet,) the covering of nearly all the completed earth filling with small boulders as a temporary protection against the dash of the sea, and the construction of a strong stone pile jetty, sunk one-half in the clay and surrounded with a good base or offset of concrete, to protect the west corner of the wall of south head, and a dry wall, some six feet high, was placed to give temporary protection to the bank of drift between the walls of the two heads.

The following is the statement of the funds available and expended during the year ending June 30, 1869, for Great Brewster Island: On hand July 1, 1868, from direct appropriation...

$547 85

Received during the year from appropriation for "repair, preservation, extension, and completion of certain public works on rivers and harbors".

Allotted from appropriation for "improvement of rivers and harbors".

10, 000 00

25, 000 00

Expended during the year..

35, 547 85

8, 625 87

Remaining available July 1, 1869..

26, 921 98

I am, general, very respectfully, your most obedient,

Maj. Gen. A. A. HUMPHREYS,

H. W. BENHAM,

Brevet Major General.

Chief of Engineers.

BOSTON, MASS., August 23, 1869. GENERAL: I have the honor to make the following report of operations on the sea walls of Deer Island and Lovell's Island, for the year ending June 30, 1869.

For the wall on Deer Island, my last previous report had given the amount of wall rebuilt up to the close of the fiscal year, to wit: about 420 feet of wall (the whole) at the south head, 540 running feet, all immediately requiring repairs upon the middle head, and 206 linear feet on the north head, being the commencement of work as reported, under a contract for rebuilding all that was necessary on this north head; the whole amount of wall thus rebuilt being 1,166 running feet since I had charge of the works.

This contract, as stated in that report, required the completion of the work on the north head during that, the last working season. But my fears of delay as there stated were realized by the operations being protracted into the present season. Nearly 600 running feet of wall, however, including the backing with concrete of about fifty feet of a former repair, were rebuilt during the season, after the commencement of the fiscal year, which connected the work with the principal repair (of 250 feet in length) made by Colonel Graham in 1865.

In May of this year the work was commenced by the contractor at the north end of the part repaired by Colonel Graham, and by the close of the fiscal year about 380 running feet of wall were rebuilt and nearly completed as to the backing and paving in rear, being nearly all that the funds on hand would permit; much additional contingent expense having been incurred by the delay of the works into the present season. At the date of this report this wall is essentially completed, as far as the funds allow, and two stone pile jetties have been placed to protect the foundations, one near the middle of the wall of the north head, and the other near the center of the main face of the wall of the middle head. The whole amount of sea wall rebuilt on the north head by the contractor is about 1,200 running feet, while, in addition, a concrete backing to about 50 feet has been added to a former repair.

Had the funds sufficed, I should have judged it to be expedient to rebuild, perhaps, some 250 feet more of this wall, and to re-enforce or back with concrete the 250 feet of the repairs of 1865, which I doubt not will be needed for its security. And although there are not at this time any very defective places or parts requiring immediate repair, I should judge that a further sum of $8,000 would be advantageously expended in giving other parts of the old wall of this north head the strength and security from future injury of the parts now rebuilt.

And as to the walls on Lovell's Island, in my last annual report it was stated that contracts had then recently been made for some repairs to be given to the wall of the north head, and for the construction of a new wall of about 800 running feet to protect the southeast bluff, the stone for which, by a contract of the previous year, 1867, had mostly been delivered and was near the site of the wall.

This wall of the southeast bluff is in a less exposed situation than that of the north head, though one more open to the sea than any other as near the main channel, except at Long Island head. I had planned for the minimum of material and expense that I thought possible to use, and it has been planned and built with about twenty-five per cent. less of cross-section and height than that model and successful work of General Thayer, built some thirty-five years ago, at the north head of this island. This wall was arranged to protect the about 800 feet

the length of the bluff with a middle face of 250 feet, and one of 200 running feet at each end of this thrown back to the shore about three degrees, with wing walls of some 50 to 60 feet, at angles of forty-five degrees to the banks at the outer extremities of these last faces. The wall was laid about three feet in the clay below, and some 10 to 20 feet without the high water-line; the foundation having two feet rise, by 6 feet 6 inches width, and the wall above of four courses, 8 feet of stone facing with concrete backing, 5 feet six inches in width, the three lower courses being of headers and stretchers with cut dovetailed joints, bed and builds, and the coping of four feet in width by two feet in height, with indented joints; that is, alternately of double dovetailed headers, and of lozenge, or rather truncated lozenge-shaped stone binding the whole course together against the displacement of any single stone. This device had occurred to me many years ago, though I have not tried it previously, and the wall and coping after being well backed up with earth was paved in the rear, for some 15 feet in width, with good-sized boulders, as the least expensive protection; and the four angles of the face of the main wall were protected with stone pile jetties 6 to 8 feet wide, projecting obliquely about 25 to 27 feet outward. The piles of 6 to 8 feet height are sunk one-half in the clay of the sloping shore, and have a base or offset of concrete in this clay, 2 to 3 feet in cross-sections on both sides and at the end.

This wall was commenced, as agreed upon, in July of last year, and steadily carried on to its completion, as above described, by the month. of December, and I have the pleasure of reporting it, after a recent examination, as answering the purpose desired in the most satisfactory manner possible. It is, in fact, more perfect now-more consolidated in rear and more filled up by shingle in front even to half its heightthan the day it was finished, while it appears to be of ample height to give all the protection required.

From the early closing of the last autumn season, the required repairs were not given to the wall of the north head; but in May of this year, these were essentially completed by the placing of two stone pile jetties (of the character of those placed at the angles of the new wall of the southeast bluff) upon the most exposed and most injured portions of this north head wall, at its convex part, near the east end, one jetty being placed about 100 feet from the east extremity of the wall, and the other about 125 feet further to the west. The foundation of the wall between the jetties, and on either side for some 40 feet, or for 150 feet altogether, was secured by an apron facing of upright stone piles, sunk some 3 feet in the clay, with an outside protection of concrete 23 feet wide and deep, the piles rising to the first or second courses of the stone facing of the main wall.

Some further repairs would have been given to the jetty at the west end of the north head wall had the necessary stone been on hand, and the funds available. But in the want of this, and the necessary protection having been given to the parts most injured on the wall of this head, the work was closed by June of this year.

The following is the statement of funds available and expended dur ing the year ending June 30, 1869, for both works:

On hand July 1, 1868, from direct appropriation

On hand July 1, 1868, from appropriation for "improving

harbor at Boston"

$2,515 30

5, 000 00

7,515 30

Received from United States treasury during the year, from appropriation for "improving harbor at Boston".

$43,000 00

50,515 30

Expended during the year

43, 245 16

Remaining available July 1, 1869, in sub-treasury...

I am, sir, very respectfully, your most obedient,

7,270 14

H. W. BENHAM,
Brevet Major General.

Maj. Gen. A. A. HUMPHREYS,

Chief of Engineers.

CUSTOM-HOUSE, BOSTON,

Collector's Office, August 24, 1869.

SIR: I am in receipt of your communication of the 20th instant, and in answer to your inquiries would state as follows:

1. The amount of revenue collected at this port during the year ending June 30, 1869, was $18,076,566 97.

2. The number and tonnage of vessels which entered at this port during the year ending June 30, 1869, are

The "coastwise" does not include vessels in the coastwise trade sailing under a license. Of these there are about 300, making several trips during the year.

The number of tons registered, enrolled and licensed vessels, for the year ending June 30, 1869, was about three hundred and forty thousand tons, new measurement.

It is safe to say, that during the past year fourteen thousand vessels arrived and sailed from Boston Harbor. Their capacity may be estimated as at least two millions of tons. All these are benefited by the improvements in and about Boston Harbor.

Very respectfully, your obedient servant,

THOMAS RUSSELL, Collector.

APPENDIX U.

I.-Report on the Saco River improvements, for the year ending June 30, 1869, by Brevet Brigadier General George Thom, lieutenant colonel of engineers.

The plan, which has received the approval of the department, for the improvement of Saco River, consists in the rebuilding of some of the