. *sV, f£. Note.—I n preparing these sketches for the Engraver the Draughtsman has omitted to show rip-rap ou cither side of the wall, as well as stay piles in the rear, all of which have been placed in this method of construction. Ccvrvctf/ sc ft. Amer.can Photo-Lithographic Co.N.Y.' Oi* c --.\pr Jc »,n * ' ■' • . . American Photo-Lithographic Co.N.Y.tO«Wne»Proc«sO i7 to the rear of the bulkhead wall, who were of necessity cut off from the street during the progress of the construction of the wall. **###### The bulkhead wall on this section, iio feet of which has been finished, foundation up to stone facing for a distance of So feet built, and pile work for 60 feet more ready for con¬ creting, is a subject on which I will have to dwell at some length, as the method of constructing it differs materially from that used at the Battery and Christopher street sections. At the latter works the system was—to drive piles, cut them off at a fixed distance from mean low water, and upon them to place prepared beton blocks by means of ioo-ton derrick and divers. On this section, as well as the King street* section, the piles are punched down, and loose concrete laid en masse in a false work of timber, which is subsequently removed. I will more particularly describe the operations hereafter. In Great Britain, and in the continental countries of Europe, where the dicta of science are as unhesitatingly received as the truths of Scripture, it would be considered ludicrous for an engineer to give his reasons in extenso for the adoption of any particular system of construction ; but in this liberal country, where the people are sovereign, and every newspaper reader is transformed into a remorseless critic, it is unsafe to originate any plan without giving un¬ answerable reasons therefor, particularly when the plan must necessarily extend over a period of many years, and involve in its completion an outlay of from $25,000,000 to $50,000,000. This must be my excuse for the collation of the following excerpts, which are familiar to every well read engineer. That eminent authority, Mr. Thomas Stevenson, in his work on the “ Design and Construction of Harbors,” at page 201, says : “Sir John Hawkshaw has passed concrete through 50 feet of water with perfect success. As far as his experience went, the concrete set quite as well under these circum¬ stances, as when it was deposited in the open air. He has 2 i8 done this both in salt and fresh water. In passing concrete through water, he used a box containing almost 2 cubic yards ; when it reached bottom, a bolt was withdrawn, and the concrete dropped out.” The same authority, on page 202 of the same work, also says : “ Mr. W. Parkes put in the foundation of the iron light-house in the Red Sea by means of a caisson, into which the fluid concrete in bags was deposited.” He thus describes the method of construction : “ During this time some progress was made at the light-house works. The caisson of iron-plates to inclose the concrete base had been deposited upon the reef, where it was exposed to a wash sufficient to remove some of its clayey particles, without carrying it opt of reach. As soon as a sufficient quantity of gravel was accumulated, the process of depositing the con¬ crete was commenced. As circumstances did not admit of the usual plan of depositing the concrete in the water in large masses from boxes, the following plan was substituted: Sheets of tarred canvas were prepared of such sizes as would fill up the spaces between the piles, and allow 2 feet round each side, to be turned up, so as to form large shallow bags. The edges of the tarpaulin were then lashed to the wooden rods, which were slung to the piles, so as to allow the tarpaulin bag to float slackly on the surface of the water. Two or three hours below low water the work was commenced. The concrete was mixed in the lighters moored alongside the caisson—6 measures of gravel being used with one measure of cement, and a suitable quantity of water. The materials were thrown into the centre of the canvas bag, which gradually sunk to the bottom (generally-from I to 2 feet under water), and the bag was spread out evenly over the whole area as it became filled. This was continued until the tide rose nearly to the level of the top of the deposited concrete, when the sides of the tarpaulin were drawn close over the soft mass, and lashed tight. In this way blocks of from 6 to 14 tons were deposited without the material having been subjected, in small quantities, to the action of the water. The blocks were generally hard enough on the fol- *9 lowing day to allow of the exposed parts of the tarpaulin being cut away; and so complete was the set, that casts of the cords and the edges of the tarpaulin were often sharply impressed upon the face of the concrete.” At the Canal street section, the joints of the caisson were so close, as to admit of scarcely any wash, and being in a slip with block and bridge piers on either side, the current was scarcely perceptible, consequently when the concrete was deposited, little more “ laitance ” or milkiness was visible than would have been occasioned if fresh made beton blocks prepared on land had been immersed in water. That emi¬ nent marine engineer, Sir Charles Hartley, in his valuable report on the “ Delta of the Danube,” at page 39, says: * * * << and t h e absence of divers to execute the work, induced the author, at first, to adopt the plan of building the wall on a roughly levelled foundation, by carefully lowering down masses of unset concrete within movable timber-dams, fitted in lengths of from 15 to 30 feet, to the frame-work of the piers. This plan was not adopted on a large scale, until it had been found, by repeated experiments, that the con¬ crete, when made with a sufficient quantity of Portland cement, set perfectly hard on a rocky foundation in a seaway, although lowered through the water in a semi-liquid state.” In passing the cement through the water at Canal street, two separate one-yard tubs were used, and the concrete mixed was comparatively dry and far from a semi-liquid state. At page 41 Sir Charles further says : 4 4 The spaces between the beton blocks used were filled up with newly made con¬ crete, which, searching its way under the adjacent blocks, and filling in the grooves, moulded in their sides expressly to this end, caused the whole mass to become ultimately as solid as if it consisted of but a single stone.” As to the strength of the Portland cement used, Sir John Coode, in his remarks from Hartley’s description of the “ Delta of the Danube,” at page 74, says : 44 The cement was tested by Grant’s machine to resist a tensile strain of 350 pounds per square inch, after being im- 20 mersed in water 7 days. He had made large quantities of cement in mass under water and at a considerable depth, with the proportions of I of cement to 5 of gravel; he had executed a large amount of such work for some years past, and had built a substantial sea wall to the height of 40 feet upon it.” The proportions used at Canal and King streets are almost identical—1 of cement, 2 of sand, and 5 of broken stone. At page 76, same work, Mr. Coode says : “ He had lately put down some foundations for a heavy sea work on a rough, rocky surface, where, if he had not deposited the concrete in mass upon the rock, the expense of preparing the bottom to receive the blocks would have been somewhere about twice or three times as great, and the time occupied would have been three or four times as long as was required to execute the works by means of concrete deposited ‘ in situ’ upon the bottom in 16 feet of water at the lowest spring tides.” I further give some excerpts taken from the reports of the Institute of Civil Engineers, London, Vol. 1862-3, a paper by Daniel Miller, C. E., entitled “ Structures in the Sea without Coffer Dams :” “ The system of building under water by means of diving- bells and diving-dresses has been practised to a considerable extent ; and the improved apparatus, now used, gives great facilities for this kind of work ; but it is only applicable under particular circumstances, and it is also costly , besides being liable to cause delay in the progress of the work.” “ There are three modes in which concrete may be ap¬ plied for constructive purposes—building it in mass and allowing it to set before water has access to the work, as has been adopted in the construction of the walls of the Victoria Docks by Mr. Bidder, and in those of the London Docks by the late Mr. Rendel—preparing it first in blocks and allowing it to harden before being used, as employed by the late Mr. Walker, at the Dover Breakwater, and by Mr. Hawkshaw for the new sea forts for protecting the arsenals of Plymouth and Portsmouth—and depositing it in a liquid state, and 21 allowing it to set under water, as practised upon a gigantic scale by M. Noel in the construction of the large Govern¬ ment Graving Docks, at Toulon. In the latter case, hydrau¬ lic concrete has been deposited in a liquid state in the sea water at a depth of about 4° feet, forming a vast rectangular trough of beton about ioo feet wide, of the length of each dock respectively, and with walls and bottom about 16 feet thick.” Speaking of the various kinds of hydraulic limes, Mr. Miller says : “It may be useful to mention, for comparison, the proportions of some of the concretes made from these various limes. The Arden lime concrete employed by Messrs. Bell & Miller for the foundations of the large Graving Docks at Glasgow was composed of i part of ground Arden lime, I part of iron mine dust, and 41^ parts of gravel and quarry chips. The lias concrete used at the recent extension of the London Docks by Mr. Rendel consisted of— I part of blue lias lime to 6 parts of gravel and sand. The proportions adopted for the blocks of the Mole at Marseilles were 2 parts of broken stone to 1 of mortar, the latter being composed of 3 parts Tiel lime to 5 of sand.” * * * * * “ The Portland cement used at the new Westminster Bridge is harder and more compact than the greater number of build¬ ing stones, even where put down in the bed of the Thames, and where it is exposed to the running stream.” * * * “ The author had lately an opportunity of examining at Genoa the extension of one of the Moles of the harbor , the inner side of which has a vertical wall.” “The latter was in process of being constructed under water entirely of pozzuolana concfete, simply thrown into the sea from baskets, carried on men’s heads, a boarding confin¬ ing it to the shape of the wall. In a short period it set quite hard, so as to enable the upper part of the wall, which is of stone, to be built on it.” # * * * * “ Though the depth of the quay wall was not great, this shows the confidence which the Italian engineers have in concrete applied under water in a soft state. The piers of the new basin constructed by the Austrian Government at Pola, in Istria, are also 22 formed in a similar manner, of concrete, confined between rows of timber piling. But perhaps the most striking appli¬ cation on a large scale of pozzuolana concrete, is in the great Mole which protects the port of Algiers. To form the Mole, blocks ofbeton of immense size, so as to be immovable by the force of the sea, were employed, some of these formed ‘ in situ ,’ by pouring the concrete into large timber cases without bottoms, sunk in the sea in the line of the Mole.” “ Hydraulic concrete, to be effective, requires great care and attention in its manipulation and in the regulation of the proper proportions of its materials.” “ Any failures must have arisen from inattention to these or similar points, as there is ample experience to show, that when properly made, every confidence may be placed in the strength and durability.” In the construction of the Albert Harbor, Greenock, the following occurs, same authority: “ The mode in which the work was designed was to form the walls under low water, of a combination of cast-iron guide piles in front, with a con¬ tinuous stone facing, slid down over and inclosing these, and of concrete backing deposited in a soft state, all of which could be easily accomplished from above the water line.” * This plan was felt to be so novel, par¬ ticularly as regards the concrete, that, though the Trustees as a body had the greatest confidence in the engineers (Messrs. Bell & Smith), they considered it to be their duty, before proceeding with the work, to fortify themselves by having the opinion of another engineer ; accordingly Mr. Thomas Page, M. Inst. C. E., was consulted, who fully sat¬ isfied them as to the efficiency of hydraulic concrete applied in the manner proposed, and otherwise confirmed the sound¬ ness of the principles upon which the works were designed. Again, same authority : “ Immediately after being mixed, and when brought to a proper consistency with water, it is conveyed to where it is to be used, is let down under water in the discharge boxes, and in a short time sets very hard. * This mode of constructing walls in deep water, without coffer dams, has proved very successful, and a 2 3 sea pier of great solidity and durability has been formed at a comparatively moderate cost.” * # # “Temporary sheet piling or boarding, instead of loose stone, may be employed to keep the concrete in its place until it has set.” General H. G. Wright, of the United States Engineer Corps, an officer of great experience, in a letter addressed to Major-General Hamilton, late Superintendent in Charge of Yards, on the subject of Rosendale cement, among other things, says: “ Of this cement I used some 50,000 bbls. in the fort at the Tortugas, a large part of which was for foun¬ dations and walls under water; the particular blocks to which I referred were laid to test the workings of the tremie. * * * * They were laid in 1848, I think ; and when I left in 1856, they were in as good condition as when laid, the surfaces being apparently as perfect. The concrete was made with sea water, no fresh water having been used.” In a subsequent statement, more particularly on the working of the tremie system , made lately, that eminent officer said, “The success attending (the above) induced him to construct the foundation of several of the forts in Southern waters in a similar manner, and with like success.” Forts Jefferson and Carroll he cited as prominent examples. •“ # * * * Should not hesitate to construct foun¬ dations under water, by depositing liquid concrete in mass % if care was taken in its manipulation.” Besides the valuable experience of General Wright, as above detailed, to my own knowledge mass concrete has been used in this country in the construction of foundations below water for a period of twenty-five years at least. While Engineer of the Brooklyn Navy Yard I constructed a wall en masse , which is a standing witness to-day of the success of the system. My predecessor in office there used somewhat similar means. Mr. McElroy’s wall at the Wall- about would have proved a success if attention had been given to the placing of more piles in the foundation, and had the Rosendale cement used, retained its previously high character, and not deteriorated in its tensile strength. 24 I will now briefly describe the method of placing this mass concrete in situ on the works in question. The wall, up to within 2' 2 T \" (two feet two and seven- sixteenth inches) of mean low water, is made of a huge mon¬ olith of concrete en masse manufactured on the spot and deposited in situ. The site for the wall was first, thoroughly dredged to a mean depth of 20 feet below mean low water ; piles were then driven, 8 in a cross section of 17 feet 6 inches, and of an average distance of 2 feet 6 inches from centres, except the two front rows, which are centred two feet ; longitudinally the outer and inner rows were driven as close as could be done without interference ; they were punched to about a mean distance of 13 feet below mean low water, by means of a heavy oak follower 26 feet in length and 12 inches in section, armed at the bottom with an iron pintle and banded with iron to strengthen against fracture ; this punching obvi¬ ated the cutting off of any other than the westerly row, and those only for a distance of 180 feet; this uneven punching afforded a good grasp to the concrete around their heads. Broken stone, measuring about 4 cubic inches, was then filled in between the piles and allowed to take a bearing. The false work for receiving the concrete was then erected. Yellow pine square piles, 12 inches by 12 inches in section, and of an average length of 40 feet, were driven in front of the westerly row of punched piles at a batter of 1^ inches to the foot, and on the back at a batter of y 2 inch to the foot, centred longitudinally 8 feet; to the inside of these square piles, previous to their being driven, battens of 4 inches by 2 y 2 inches spruce were nailed on firmly, and on these further pieces of spruce, 12 inches by 2 inches, were fastened, form¬ ing grooves for receiving constructed wooden shutters or gates which were slid into place after the pile alignment was perfected. These piles were then capped crosswise by square 12-inch timber, braced laterally by walling pieces 12x6", and on these cross caps stringers were laid, on which were placed rails of flat iron to receive the wheels of a movable platform car, bearing on it a 10 horse-power engine for the lowering 25 of the concrete into the caisson. This platform car had erected on it a gallows frame holding traverse wheels with pendant bales of iron, from which were suspended double block purchases for the lowering and hoisting of two separate i-yard buckets, each working from a separate drum indepen¬ dent of the other, so that one bucket could be lowered while the other was filled. The concrete was mixed on a platform in the rear, con¬ structed on the stay piles driven in the rear of the wall, wheeled to the car, dumped into the buckets or tubs, and then lowered into the caisson. The door of the bucket being opened from above by a trap rope, did away with the necessity of employing divers, and the only occasion when divers were used at all was when Mr. McDonald, foreman of masons, himself a practical diver, levelled off the top layer of concrete to receive the granite facing. The buckets could be shifted from above in such a manner as to command any portion of the bottom. The proportions of the concrete varied occasionally, but the usual proportions were, as before stated, I, 2, and 5, or 1 part cement (Portland), 2 of sharp sand, and 5 of small broken stone. Concreting was commenced on the 24th of December last and continued until the 6th of January, 1875, a layer of 2 feet being spread over the bottom, soaking into the broken stones at the bottom, and binding the pile heads firmly to¬ gether. The quantity of ice by this time proving very troublesome, concreting was suspended until the middle of March (though further piling for the wall was continued throughout the winter, with scarcely any intermission), and vigorously prosecuted until the end of April, when the whole mass necessary was placed. In the hearting of the caisson, one-fifth of granite spawls, from the Departmental Stone Yard, were placed and thoroughly grouted, preserving the stability of the wall and lessening the expense. In placing the concrete in water, chilled sometimes to 3 0 colder than the freezing point of fresh water, some means had to be adopted to counteract its chilliness. That eminent 26 and versatile engineer, Mr. Chanute, in his report on the Kansas City Bridge, says : “Both masonry and beton were laid in extremely cold weather, the use of hot sand and water being found to make this practicable. The sand was heated in large sheet iron braziers, and the water warmed in cast-iron kettles, one of each being found sufficient to supply the force working on a pier. The heat which was thus artificially given to the mor¬ tar hastened its setting, causing this to take place before the mass had cooled enough to make freezing possible.” Mr. T. C. Clarke, in his able and exhaustive report on the Quincy Bridge, says : “During this time the glass fell as low as 16 ° Fahr. A shanty was built on a flat, and in this a kettle was placed on a stove, and the cement mixed with hot water. During the coldest days each stone was, before being set, held over a brazier of charcoal to draw out the frost. The mortar Was examined carefully in the spring, and found to be as hard and perfect as any on the work. Much of the masonry of this bridge was constructed during winter, although none in as cold weather as this pier, and there is apparently no dif¬ ference in the quality of the mortar whether built in winter or summer As the quantity of cement used by these gentlemen was very small in comparison with that which would have to be used in the bulkhead wall in question, some means had to be taken of a more extensive nature. For heating the water, the following simple apparatus was used. A cask capable of containing 60 gallons of water, holding a coil pipe, was placed on the movable car, and through this coil the steam from the boiler of the engine was passed at will ; this heating was done very rapidly and efficiently, it only taking from 4 to 8 minutes to heat the whole 60 gallons from 32° to ioo° -Fahr., the water thus heated being carried to the mixing platform by india-rubber tubing. To heat the sand and broken stone, heaters made of iron, similar to those used in street paving, were constructed by Mr. Joseph Edwards, 414 Water street, New York, each capable of heating a cubic yard of material, 27 the fuel used being old barrel staves, etc. They did their work thoroughly, and by this means work was carried on, on one occasion when the temperature of the air was ii° Fahr. and that of the water 32°, the concrete becoming as hard as if made during the hottest summer months, thus practically substantiating the opinions of Messrs. Chanute and Clarke. In laying the backing to the granite facing I have intro¬ duced a change from that at Christopher street section, which has materially lessened the expense, while preserving the stability of the wall. Blocks of about three cubic yards capacity were made at the Seventeenth street yard out of old granite spawls and Portland cement; when sufficiently compact they were transported to Canal street, and placed in position with great rapidity, over 70 lineal feet being laid during one tide. The success attending the use of these rubble blocks has been such that I have recommended to the Board in my report on the “ Development of the Harlem River and Spuyten Duyvil Creek for Commercial Purposes/' that the bulkhead wall when constructed should be composed of beton placed en masse with a rubble masonry facing sur¬ mounted by a granite cope. On the removal of the shutters and square piles—the false work of the caisson—which had been down nearly three months, Mr. McDonald carefully examined the sides of the monolith and reported that he found it as smooth and com¬ pact in appearance as any blocks he had ever seen which were manufactured on land—and no sign of honey-comb. This assertion was verified by my assistants, who passed a boat hook all along the sides both front and rear, and found it as smooth as the Gansevoort street manufactured blocks ; the edges of the berme,” too, 6 inches in width where the stone facing springs from the monolith of concrete, was as distinctly defined as that of a well cut piece of granite. A great saving has been effected by this system of construction, over that of the block system, including coping not as yet required on this section (the wall constructed being in the wake of the pier); the saving amounts to $67.77 P er foot 28 run, or over $350,000 per mile, the cost per foot run being $311.67. By having a long stretch of work, a judicious use of labor, and using made rubble blocks surmounted by granite cope, instead of cut facing, I am of the opinion that the cost can be reduced at least 20 per cent. It is worthy of notice, before leaving this section, that in the pile foundation, now waiting stone-packing, driven to the north of the already completed wall, 207 old piles, drawn up from the north half of old Pier 42, and which had been down for a period of over 25 years, were driven in the foundation, the only fact noticeable being, that a few of the heads required recutting ; otherwise they were as good as the day they first were driven. King Street Section. The dredging for the river wall between old piers num¬ bers 45 and 46 was begun November 16, 1874, and amounted to 3,600 cubic yards. The foundation is to be 175^ by 147 feet, and 678 piles were driven. The caisson, 147 feet long, is constructed in the same manner with that at Canal street, and 626 cubic yards of 4-inch stone have been thrown in, and 1,225 cubic yards of rip-rap stone have been placed in front and rear of the caisson. Gansevoort Street Yard. The following alterations were made at Gansevoort street yard, during the year : The manufacture of beton blocks for the river wall being no longer carried on at this yard, the platforms upon which about 9,300 cubic yards had been made during the previous two years, were removed. 29 The preparations for surrounding yard number 3, involved the removal of a large amount of varied stores and mate¬ rials. The grade of the yards and bulkhead was raised an aver¬ age of three feet, to conform to the new level established, with ashes and like material delivered by the Street Cleaning Department. A new blacksmith shop was built in the middle yard ; the grade of the store-house floor was changed, and one-half of the large store-house was partitioned off into small store-rooms for the floating property, and repairs and supplies, and an office, leaving the other half, which is 164 feet long by 24 feet wide, for the storage of cement, with a capacity of 3,400 barrels. The fences and gates of all the yards were also raised. Yards hitherto known as “yards numbers I and 3 ” have been turned over to the Commissioners of the Sinking Fund, yard number 2, with one pier, being retained for the uses of this Department. The dimensions of yard number 2 are 163 feet in length by 52 feet in width, in which has been built the new blacksmith shop, the remaining space being occupied by a shed for forge coal, a bin for hard coal, containing about 39 tons, and for the storage of wheelbarrows, lumber, beton moulds, and miscellaneous material. For a detailed statement of purchases, receipts, and de¬ liveries of every description, and of articles manufactured, and stock on hand, reference is requested to the returns from Gansevoort street yard in the “Appendix ” accompanying this report. East Seventeenth Street Yard. During the year about 1,300 feet of narrow-gauge railway has been constructed at this yard, at an average cost of one dollar per running foot. This, with four cars, made at the yard—two for cement and two for granite—greatly reduces the 30 cost of loading and unloading stone and cement. The rail¬ road also renders every part of the yard available for storing stone, while formerly only the bulkhead could be used for that purpose. The store-house, besides the portion used for storing iron bolts, and small articles, and the carpenter’s shop, can con¬ veniently receive about 5,000 barrels of cement. The blacksmith’s shop contains four forges, three of which would be sufficient to sharpen tools fora force of thirty stone¬ cutters, and the remaining forge could be used for any gen¬ eral blacksmith work required by the Department along the East river front. The cost of stone-cutting for the year, at $1.42 per cubic foot, is less than the same work could be done for by con¬ tract. This result has been attained by the system of keep¬ ing an account of the work done by each stone-cutter, and requiring all to come up to a certain standard. The yard itself possesses great advantages, either for cutting stone or simply for storing it until required for use at the several sec¬ tions. Besides the space occupied by buildings, it has an area of 2\ acres, available for storage purposes, with a bulk¬ head front of 645 lineal feet. Between April 10th and May 14th, 1875, there were manufactured at this yard 36 rubble blocks, at a cost of $9.77 per cubic yard. The first 18 of these blocks cost $10.70 per cubic yard, and the last 18 cost but $8.84 per cubic yard ; the lesser cost of the latter being due to the fact that the plat¬ forms upon which they were built were all finished for the first lot, and, consequently, no carpenter work enters into the estimate. Floating Property. The floating property of the Department of Docks is as follows : Three tug-boats, in good condition, with the exception of the Louis, undergoing repairs. 3 1 Four dredges, all in good condition. Nine pile-drivers, all in good condition, except “ No. 6.” Eighteen mud-scows, all in good condition except four. One patrol-boat. Eleven deck scows—four of them new. One boring machine, for taking soundings. For details of floating property and of dredging, etc., performed during the year, see “ Appendix. ” General Repairs. The general repairs to old piers and other structures, per¬ formed since February i, 1875, at which time work of this class was placed under my supervision, were as follows : The dumping-board at the foot of Forty-sixth street, East river, was repaired on the 10th of February, and again on the 4th of March. At Blackwell’s Island three platforms were built, for the use of the Police Department scows, and of the following dimensions: 51x31^ feet; 43x32 feet; and 41x26 feet; constructed between February 27th and March 10th. At Randall’s Island an extension on a pier was built, 23 feet long by 7 4 feet wide, from March 9th to 19th. Repairs were made on Piers Nos. 40 and 41, East river, February 26th to March 26th ; Pier No. 6, East river, March 20th to 23d ; Pier No. 7, East river, March 25th to April 5th. These repairs consisted mainly in work at the outer ends of the piers, which had been damaged by the ice, as in putting on fenders, corner bands, clusters and spring piles. The bulkhead between Gansevoort street and Little Twelfth street was raised two feet, for a length of 733 feet, to conform to the grade of Thirteenth avenue, between March 20th and April 6th. The bulkhead at the foot of East Seventeenth street was repaired and strengthened, fora length of 450 feet, by driving down 49 piles, April 2d to 10th. 32 Pier No. 37, East river, was repaired, with spring piles, chocks, and fenders, April 6th to 14th. The pier at the foot of Twenty-eighth street, East river, was repaired, with new fenders and backing logs, April 14th to 19th. The pier at the foot of Twenty-fourth street, North river, was extended, 50 by 50 feet, April 14th to May 5th. A platform, 100 feet long, extending out 20 feet, was built against the bulkhead at the foot of One Hundred and Thirtieth street, North river, April 16th to 24th. Pier 46, East river, was repaired, April 21st to 27th ; the pier at the foot of Forty-sixth street, North river, April 26th to 27th ; the pier at the foot of One Hundred and Fifty-fifth street, North river, April 26th; the pier at the foot of Twenty-sixth street, North river, April 27th to 30th ; the bulkhead between piers Nos. 45 and 46, East river, April 28th to May 1st, and the pier at the foot of Forty-seventh street, North river, April 27th to May 1st. A cluster of piles was driven and secured to the end of Pier No. 38, East river, to keep vessels off the old block. On the 30th of April the following works were in progress : Repairs at the foot of Twenty-fifth street, North river ; at Fifty-first street, North river ; and the tearing up of the pier at the foot of Ninety-sixth street, North river. The damage to piers from floating ice has been unusually severe during the past winter. Ninety piles were cut from under the pier at the foot of One Hundred and Twenty-ninth street, North river, leaving the deck unsupported for about 100 feet. All but about 50 feet of the pier at the foot of Ninety-sixth street, North river, was entirely carried away, and, on the East river, the ends of Piers Nos. 12 and 38 were entirely wrecked. For the general repairs performed prior to February 1st, 1875, under the supervision of the Superintendent of Repairs and Supplies, and for more minute details of work accom¬ plished, I would refer to the “Appendix ” accompanying this report. 33 Harlem River. The great difficulty which has thus far prevented the im¬ provement of the Harlem river has been the clashing of authority, delegated by the Legislature to the different com¬ missions. April 15th, 18"i, an act was passed giving the Depart¬ ment of Public Parks full power “ to build or construct, by contract or otherwise, any and all improvements in the navigation of Harlem river and Spuyten Duyvil creek, which said Department might plan or locate.” Three days after the passage of the above act another was passed, which amended the “act creating the Department of Docks,” and provided that the plans of this Department, when confirmed by the Commissioners of the Sinking Fund, should constitute the sole authority for the solid filling in the waters surrounding the City of New York, and repealing all other provisions of law regulating solid filling and pier and bulkhead lines in said waters. Thus by the latest act the “ Department of Docks ” was given the authority, with the confirmation of the Sinking Fund Commissioners, to lawfully supersede any lines estab¬ lished by the Park Commissioners or by any other commis¬ sion. The authority to determine upon a plan or plans for the improvement of the whole or any part of the water front of the city, was so clearly the prerogative of the Department of Docks, that the Park Commissioners, in a report to the Senate April 1st, 1872, made use of the following language: “A question having arisen as to the jurisdiction of the Board over the Harlem river, the work, so far as related to special hydrographic objects was suspended, and only so much as relates to other objects has since been continued. In March, 1872, the Commissioners of the Department of Docks submitted to the Commissioners of the Sinking Fund new pier and bulkhead lines for that part of the city north of 3 34 Sixty-first street, including the Harlem river and Spuyten Duyvil creek. These lines were neither accepted nor re¬ jected by the Sinking Fund Commissioners. Although as far as the Harlem river was concerned, it made but little difference, as the lines submitted by the Dock Commissioners were almost identical with the then existing lines which had been made by the Park Commissioners in 1868. In this condition of affairs the new Charter was passed April 30th, 1873, which rescinded the authority previously delegated to the Department of Docks, and in the following language it is claimed by the Department of Parks, confirmed their lines : “ There shall be a Department of Docks, the head of which shall be a Board consisting of three persons, * * * who shall possess such power and perform such duties, as are now possessed by the existing Department of Docks, but said Board shall not have the power to change the exterior line of piers and bulkheads as now established by law.” The Charter by taking away the power from the Depart¬ ment of Docks to establish pier and bulkhead lines effectually suspends the improvement of the Harlem river, for no im¬ provement of a permanent character and based upon a knowl¬ edge of the tidal laws in this and the Hudson river, can take place, until the existing lines in this locality are changed, or, in other words, until the section of the improved river, instead of being contracted in Spuyten Duyvil creek is made as wide or wider than the Harlem river. In brief, the whole improvement of the Harlem river and Spuyten Duyvil creek consists in so adjusting the lines of solid filling, as that the best interchange of tides between the East and Hudson rivers may take place ; and, inasmuch as the existing lines were planned without any reference to the flow of the tides, to have them legally changed is the first step towards the improvement of these rivers. In April, 1874, the Legislature passed a joint resolution, calling upon the Department of Docks to make the necessary surveys and soundings from the mouth of the Bronx river to the southerly boundary of Yonkers, in the recently annexed 35 Twenty-third and Twenty-fourth Wards. Instead of at once entering upon the survey, with the view of giving the city an accurate map of the water front in these wards—a want which is still severely felt by those holding property along the Harlem river—nothing was done in the matter. The very full reports furnished by me in relation to this survey, and which accompanied the recent report of the Com¬ missioners in answer to the concurrent resolution of inquiry by the last Legislature as to the reason of the work not having been prosecuted, contain the reasons, in detail, why the nu¬ merous surveys that have been made in this region from time to time do not meet the present wants. The assertion contained in these reports that “ No com¬ plete hydrographic map of the Harlem river, Spuyten Duy- vil creek, and the water front of the recently annexed Twenty-third and Twenty-fourth Wards, exists at the present time ” is still true, notwithstanding the recent survey made by General Newton. This, while an excellent one of its kind, and useful for certain purposes, entirely fails to fur¬ nish the detailed information required to locate the water front of a rapidly-growing city, nor could it be considered as anything more than a preliminary survey, in the event of any extensive river improvement being entered upon. The survey called for by the resolution above mentioned, is required, whether the Harlem river be improved or not; but should any measure be adopted for the readjustment of its bulkhead lines, the necessity for this survey will be more apparent than ever. Should the Department of Docks be vested with the power, by the Legislature, to establish permanent lines for the solid filling on the Harlem river, these lines should be, as I have shown in a report made to this Board May 20 , 1875* either parallel lines through the Harlem river and Spuyten Duyvil creek, or lines diverging from the Harlem river, so as to increase the section of the improved river at its mouth on the Hudson. Where continuous parallel bulkhead lines are insufficient to accommodate the requirements of commerce, the system of parallel piers being entirely inadmissible in 36 consequence of the narrowness of the river, I advocate the construction of wet basins within the masonry bulkhead. The bulkhead wall, when constructed, should be com¬ posed of beton, placed in situ , with a rubble masonry facing, surmounted by a granite cope. In conclusion, I desire to express, in the most emphatic manner, the wisdom of adhering to the natural channel of the river, as proposed by the Harbor Commissioners in 1857, the Department of Parks in 1868, and the Department of Docks in 1870. Artificial channels, for the purpose of making short cuts between portions of the same river, or between a river and bay, are of doubtful utility at the best, and when such a canal would, as in the present instance, intercept established lines of communication between the city and the recently annexed territory, and destroy the value of a vast amount of property which has already been partially improved with a prospective view to its occupation for commercial purposes, its construction should not be thought of. North River. In 1834 Commissioners were appointed by the States of New York and New Jersey, to define the boundary line be¬ tween these two States in the Hudson river and New York bay, and their report was ratified and confirmed by their respective Legislatures and by Congress. If some joint action of this kind had been taken by the two States, in 1855, when New York appointed a Commission “ for the preservation of the harbor,” the vexed question of encroachment in the coterminous waters of New York and New Jersey might have been settled forever. That the New York Harbor Commissioners were fully sensible of the fact that their work would only be half done, unless in some way it could receive the sanction and co¬ operation of New Jersey, we can see from their report in 37 which they say : “ It was obvious that the preservation of the harbor, and a just regard to the interests of the States, required that proper limits should be defined on either shore, and that these limits ought to be simultaneously determined. If, in the absence of restrictions, piers were unduly projected into the river from one shore, they might have an injurious influence on the other; or, if from both, there was reason to apprehend that the navigation of the river would be affected.” Entertaining these views, the New York Harbor Com¬ missioners addressed a communication to Governor R. M. Price, of New Jersey, asking him whether, if they laid pier and bulkhead lines for both States, they would be accepted by the State of New Jersey. To this the Governor responded that any lines laid down for the New Jersey shore, while they would be received with great confidence for impartiality, could not be legally fixed or accepted without being confirmed by the respective Legis¬ latures of New York and New Jersey, and by the Congress of the United States. Here the matter rested. The New York Harbor Com¬ missioners laid down pier and bulkhead lines for both shores in the Hudson river and New York bay, but they were never accepted by New Jersey. In 1865 a report was made by Commissioners appointed by the Legislature of New Jersey, which contained a survey of the land lying under the waters of the Hudson river and New York bay, with proposed pier and bulkhead lines for this locality. The lines laid down by this Commission are the governing lines, I believe, at the present date. Whether they were de¬ termined with any reference to maintaining the capacity of the Hudson river as a tidal reservoir, and thereby keeping the channel at Sandy Hook the same, or whether the more narrow policy of looking after local interests merely prevailed, I am unable to state; but I should think the subject impor¬ tant enough to warrant the appointment of a joint' commis¬ sion by both States, and after their report shall have been 1 38 made, to lay the matter before Congress for final confirmation, just as was done in the boundary question in 1834. It seems not a little curious that such an important ques¬ tion, in which both States are equally interested, should have slumbered so long ; and not only New York and New Jer¬ sey, but the Federal Government itself, is interested in pre¬ serving the best harbor of the country, which yields by far the largest revenue. The most thorough and intelligent representation of the whole subject was made by the Harbor Commissioners, in 1856, to both State Governments ; and it is to be much re¬ gretted that in neither State have their lines been adhered to in the controlling sections of the Hudson river. The gradual but constant advancement of Sandy Hook toward the channels from the ocean, will, at some future date, seriously affect the commercial supremacy of the port. With¬ in a century it has increased a mile and a quarter, and in the twelve years from 1844 to 1856, it advanced a quarter of a mile. Various causes have been assigned for this alarming pro¬ gression ; but while no one of them seems sufficient to pro¬ duce the result, it probably arises from several. Among the principal of these, are the indiscriminate dumping of ashes and other solid material in all parts of the harbor, and the extension of the pier and bulkhead lines at points where the river should not be contracted, and which has resulted in the partial exclusion of the tidal waters. East River. I would respectfully suggest, in connection with the pro¬ posed improvements on the East river water front, that this work should not be entered upon by the Department until the modifications and changes in the existing lines, as re¬ commended in my letters to the Board of February 12, and March 16, 1875, shall be authorized by the Legislature. 39 These changes contemplate, first, a reduction in the width of the river street, from the Battery to Corlear’s Hook, and in the length of the piers in the same locality; and, secondly, to omit altogether the precise location of the new piers, establishing merely the pier and bulkhead lines. De¬ termining the location and dimensions of new piers in advance of the demand for them, is productive of serious embarrassment to the Department, and I am firmly con¬ vinced that all that is required in reference to these piers, at this time, is the establishment by the city of a pier line or limit of encroachment, beyond which no structure should be permitted. It should by no means, however, be made obligatory on the Department to carry all their piers out to this line ; on the contrary, specific dimensions should be left to the dis¬ cretion of the Board of Commissioners, and should be decided from time to time, by the demands of commerce in each locality, as well as by the ascertained configuration of the shore and river bed. The width of the channel in the East river upon which the calculations of General McClellan were based, for the lines proposed in 1870, has been materially reduced since then by the extensive and unrestrained construction of solid bulk¬ heads and projecting works on the Brooklyn side. This shows the necessity of the Legislature fixing the limits on both shores simultaneously, and with reference to the preservation of the harbor. Fortunately, in this case, both sides of the river are within the jurisdiction of the same State, and we do not have the complication which exists in the settlement of similar ques¬ tions affecting the Hudson river side of the city, of a treaty with New Jersey, and the necessity of its ratification by the Congress of the United States. The Contract System. In my judgment, derived from my experience in the con¬ struction of the several works described in this report, the 40 contract system cannot be economically or successfully applied in carrying out the plans of this department. It will at all times be necessary so to manage operations on any given section of the river-wall and the slips and piers belong¬ ing thereto, as to cause the least possible obstruction to commerce, and this will involve as at the Christopher street and Canal street sections, the construction, maintenance, modification, and removal, of a system of temporary con¬ nections, and the like, which, from the very nature of the case, could not be foreseen and calculated with sufficient accuracy to admit of proper description in specifications for a contract. On the other hand, should a contract for any such work be made without provision for such inevitable in¬ terruptions and outlays, the city would be involved in inter¬ minable disputes, as well as made liable to vexatious claims for damages and demurrage. In view of this necessity of dispensing with the contract system on all new work, I have steadily endeavored so to simplify the method of construction as to admit of the em¬ ployment of the largest possible proportion of unskilled labor ; and it had been my intention to still further extend the application of this idea upon the works yet to be undertaken. A striking commentary upon the undesirable nature of the contract system, in connection with structures upon whose constant use the commerce of the city is necessarily depend¬ ent, is to be found in the history of our general repairs,, during the past season. The piers at the foot of Clintor* street, East river (No. 38), and at the foot of One Hundred and Twenty-ninth street, North river, were carried away by the ice on the 18th of March, and the proposals for contracts for rebuilding them were opened on the nth of June. If we suppose these piers, instead of being in localities where the demand for their use was comparatively unimportant, had been in the lower part of the city, say near the foot of War¬ ren street, it will at once appear that the system which would have deprived commerce of their use for so long a time, must be radically defective. In any extended destruction of wharf property, by fire or flood, the contract system would 4i be found an incomparably greater calamity than either the flood or the fire. Neither is it true that the city cannot find honest and capable servants, who will so manage the duties intrusted to them, as to insure economy as well as all other desirable results. Conclusion. In time of war it is customary to commend the gallant acts and daring exploits of individuals in the official reports. Why this custom has not been more generally extended to the pursuits of civil life, has often been a matter of surprise to me. Peace has her victories as well as war, and churlish indeed must be the leader, in a great civil work, who with¬ holds from his subordinates the meed of praise which is their due. Coming into the Department an entire stranger, I should have been much embarrassed, but for the loyalty of certain gentlemen to the profession to which they and I belong. Conspicuous among these was Mr. John D. Van Buren, Jr., late Assistant Engineer of this Department, and now a member of the State Commission for the investigation of canal frauds. In the construction of the works at Christo¬ pher street, of which he had the immediate supervision, Mr. Van Buren, by his professional attainments, his untiring in¬ dustry, and his strict integrity of character, won my admira¬ tion and respect, and rendered this arduous undertaking a pleasure. To Mr. C. B. Kid* Assistant Engineer, formerly Mr. Van Buren’s coadjutor, and subsequently his successor, I am like¬ wise under obligations, for the unswerving fidelity as well as for the varied knowledge and skill he displayed on several trying occasions. To Capt. W. W. Maclay, the industrious and skillful Assistant Engineer, who fitted out the East Seventeenth street yard, making it the most complete work-yard in the 42 country, and carried out a system of supervision by which the labor performed by each stone-cutter could be accurately demonstrated, I owe my hearty thanks. To Mr. W. N. Radenhurst, Inspector of Engineering, who has so ably supervised the construction of the Canal street section, which may be regarded as a trial work, and who likewise assisted me on many occasions, in elaborate calculations and difficult reports relating to important sub¬ jects connected with my duties, I desire to express my most earnest appreciation. To Edward McDonald, Master Mason, whom I found a mere diver, and advanced to the most important mechanical post connected with the masonry bulkhead, I desire to ex¬ press my appreciation of his practical knowledge, steady industry, and able management of the force under his con¬ trol. Mr. Thomas Murphy, Superintendent in charge of con¬ struction at new Pier No. I, North river, is entitled to a hearty recognition of the manner in which he has performed the duties originally intrusted to him by Gen. McClellan. To Messrs. Staats, Suiveyor ; Aitken, Recorder; Rath- bone, Chainman; and to the several foremen and time¬ keepers of the various works, I likewise feel myself to be under many obligations. To Mr. W. O. Stoddard, the Chief Clerk of my office, who has supervised the labors of my desk, and assisted me by night and by day, in conducting a large correspondence and in the preparation of my reports, I feel that much praise is due. Very respectfully, Your obedient servant, • (Signed) CHARLES K. GRAHAM, Engincer-in-Chief. All the appendices referred to in the body of this Report are omitted, as this edition is merely issued for private distribution. ADDENDA. 237 Broadway, New York, ) July 13, 1875. ( On the 2d day of June last I resigned my position as Engineer- in-Chief of the Department of Docks, and on the 9th day of the same month it was accepted. Up to thjs time, in consequence of the onerous character of my duties, not a syllable of this report had been written, although it should have been in the hands of the Secretary of the Board at least a month earlier; consequently, con¬ ceiving it to be a matter of honor to prepare it before taking final leave of the Department, I remained without pay until it was com¬ pleted, on the 19th day of June. In the haste of preparation certain matters of consequence may have been omitted, and others of minor importance may have re¬ ceived more attention than was their due. In estimating its merits, I trust these facts will be taken into consideration. CHARLES K. GRAHAM. Pier No. i. Until the spring of the year 1874, all the beton blocks were manufactured at the Gansevoort street yard, and were transported in scows to the points where they were to be used; consequently the large derrick was employed at least two-thirds of the time merely for lifting purposes, and only one-third of the time in the profitable process of construction. 44 A sufficient stretch of the masonry wall having been finished adjacent to Pier No. i to allow filling in, platforms were erected on the reclaimed land and the manufacture of blocks for the pier com¬ menced there. At the same time it was deemed advisable to reduce the height of the pier blocks, as the cost of manufacturing a block 14 feet in height greatly exceeded that of one 6 or 7 feet high, and, moreover, the large derrick had been so continuously employed that it was unwise to imperil her usefulness by lifting such large masses, as in the event of a serious accident occurring to her, there was no machine, either attached to the Department or the property of private parties, which was capable of taking her place. As the large derrick was occupied a greater portion of the year 1874 on the Christopher street section, little progress could have been made at Pier No. 1 but for these changes ; and towards the close of the year when work was being prosecuted vigorously on all the sections, the reduction in the size of these blocks enabled Dela- mater’s floating derrick to be advantageously employed in placing them. As stated in my report, I at one time contemplated a change in the foundations of Pier No. 1, and in order that this proposed alter- tion may be thoroughly understood, the letter to the Board, suggest¬ ing it, is annexed. New York, March 17, 1874. Eugene T. Lynch, Esq., Secretary of the Board of Docks : Sir —As we are about to resume operations on Pier No. 1, N. R., I consider it my duty to call your attention to certain weak points in the foundations of that structure, and suggest a method by which they may be overcome, with a great saving in cost of con¬ struction and a probability that the work can be completed several months earlier by its adoption. The plan proposed by General McClellan calls for timber-cribs, filled in with concrete, upon which the sub-piers are to rest. The objection to the use of cribs are— First. The difficulty of placing them in position, owing to the force of the current. Second. The impossibility of making an accurate fit of their lower edges to the rocky bottom of the river. Third. The fact that the concrete has to be lowered through from 25 to 40 feet depth of water and deposited in the crib by divers. In the passage through the water much of the cement is removed, rendering the concrete weaker. In the process of filling, very little force can be exerted by the diver, as he has almost as 45 much as he can do to take care of himself; consequently the material cannot be properly rammed, and large openings may exist in the foundation which time alone can develop. In place of the crib foundation, I propose that a foundation of rip-rap should be placed, from the eighth crib, now ready to be laid, up to and including the pier-head, at a depth of 28 feet below mean low water. The advantages of this foundation are— First. That it can be commenced immediately and continued without interruption until it is completed. Second. That it can be weighted, as it progresses, with twice the superincumbent weight it is intended to bear, and brought to a soild bearing. Third. That the large expense incurred by and the uncertainty attending the use of divers may be, in a great measure, done away with. Fourth. That no concrete or beton will have to be employed, except that which has been properly manufactured in moulds and exposed to the air until it has been thoroughly hardened. To counterbalance these advantages, but one objection can be urged—the reduction in the water-way; but, as the reduction pro¬ posed, as will be seen by the accompanying statement, will only amount to 6 jsu per cent., and the saving in cost will alone be at least $50,000; I do not think it should be seriously entertained. Your obedient servant, (Signed) CHARLES K. GRAHAM, Engineer-in- Chief. My last important official act was to address the annexed com¬ munication to the Board. June 8, 1875. Eugene T. Lynch, Esq., Secretary of the Board of Docks ; Sir _On the 27th of January last, I had the honor to make the following reply to a communication from the Board of Com¬ missioners governing this Department : “ In response to the resolution of the Board of Commissioners governing this Department, of the 21st inst., with reference to the reduction of the proposed length of new Pier No. 1, North river, I have the honor to say, that, in my judgment, there are no engineer¬ ing difficulties in the way of the construction of that pier to a full 46 length of five hundred feet, but I submit, nevertheless, that it would be unwise to do so, for the following reasons: “ The situation of the pier is so exposed, and it is so open to the effects of the southeast winds, that, during a large part of the year, it can only be advantageously occupied on the north side : for this reason and likewise, because of the insufficient depth of water along¬ side the pier, the depth at mean low water, in some places, not ex¬ ceeding 21 or 22 feet, and of the rocky nature of the bottom, this pier can never be occupied by steamships of great length and draft. “ Moreover, this excessive length of five hundred feet would render the pier an obstacle to vessels coming in the Bay and in¬ tending to round to in slips not very distant from it. “ For reasons given above, this pier will probably be occupied, when completed, by some large railway corporation for the receipt and delivery of heavy freight. “ I now respectfully recommend that the length of Pier No. i. North river, may be reduced to 425 feet, for the reasons already assigned in the above communication, and for the following, in addition : “ 1. Mr. Isaac Newton, the Assistant Engineer, in charge of the construction of Pier No. 1, stated to me shortly after my appoint¬ ment, that he had already advised Gen. McClellan to reduce the pier to a length of 400 feet, and he has recently stated to Mr. Raden- hurst, Inspector of Engineering, that there was a letter from him to Gen. McClellan, on file, to that effect. This latter must be a mistake, however, as it cannot be found in any of the letter-books. “ 2. Scientists agree that a diver cannot work effectively in a depth of fifty feet of water, even when it is clear and free from current. “ 3. Practical divers tell me that it is impossible for them to work advantageously in a three-knot current; consequently, it is my con¬ scientious belief that if divers are employed in the increased depth of water and accelerated current at the termination of the pier as at present proposed, their operations will consist in little more than holding on to the foundation of the pier in order to prevent them¬ selves being swept away. “ 4. It will be observed that from the seventeenth arch to the pier¬ head, in a distance of seventy-five feet, the rock bottom shelves ten feet, running from 45 feet to 55 feet. “ If the pier is reduced to the length suggested, it can be com¬ pleted this season without difficulty, and at a saving to the Depart¬ ment of at least $75,000. This estimate allows for the price of the granite furnished for the entire pier, the unused part of which may be utilized on other portions of the work.” 47 - I was given to understand, at the time my above quoted com¬ munication was received, that the majority of the Board, as then constituted, was in favor of the reduction proposed, and in view of the fact that changes in its membership have since occurred, I deem it my duty at this time to renew my recommendation with reference to a permanent structure of such extent and importance. The work is now progressing so rapidly that the question in¬ volved should be settled within the ensuing month. Your obedient servant, CHARLES K. GRAHAM, Engineer-in- Chief. The entire success of the “ beton en masse system ” on the Canal and King street sections had determined me to recommend to the Board its adoption for the future construction of Pier No. i, it being my intention, if the suggestion was accepted, to substitute cribs formed of dock logs for the finished timber cribs, and to raise from them as platforms wet caissons, so that the employment of divers could be dispensed with except for the sole purpose of locat¬ ing the cribs, the employment of divers in a current of at least three knots velocity, and in a depth of water, as the pier approaches its termination of nearly 50 feet, being a dangerous and profitless oper¬ ation. Moreover, I proposed to make the pier-head foundation of two parallel cribs, at right angles with the axis of the pier, connected by two parallel cribs longitudinally placed; to fill in the cribs only with concrete, and to place rubble in the centre. The adoption of these expedients and the reduction of the length of the pier to 425 feet, which had already been strongly advised by me for reasons which, in my judgment, are incontrovertible, would enable the pier to be completed, this year, at a saving of at least $100,000. Christopher Street Section. When this section was progressing I directed Mr. Radenhurst, Inspector of Engineering, to collect all data possible to show the utter inability of wooden bulkheads, located under similar con¬ ditions, to withstand the severe lateral pressure exerted by the immense mass of earth filling they would be compelled to sustain, without such excessive distortion as would render them entirely un¬ suitable for foundations upon which to construct any masonry wall, from low water up, intended to preserve a uniform alignment, free from unsightly openings and subsidences. The result of his labors is attached: 48 Memoranda. Facts collected respecting the distortion of wooden bulkhead walls from lateral earth pressure. No. Data furnished by A. J. Murray. J. Guthrie. W. N. Radenhurst Position. 34th st. to 37th st., N. R. 38th st. to 40th st., Jane st. to 12th st., West nth st , 35th st. to 38th st., E. R. 34th st. to 35th st., 23d st. to 25th st., nth st. to 13th st., 96th st. to 100th st., 17th st., 30th st. to 33d st., (H. R. R. improvement \ 65th st., N. R. Effect of Distortion. 12 to 14 feet, out irregularly. About 7 from original line By whom built. G. White* B. Kelly. Jenks. Kelly. Earl. Kelly. 2 to 14 feet,irregularlyt Block gone irregularly some 3 or 4 feet, canting over at same time. The force of pressure not as yet felt.J Memoranda.— Some facts stated by Assistant Superintendent Guthrie in relation to the building of wooden bulkheads around the city and its environs : “ The bulkheads deviate from original line principally from faulty construction; too rapid filling in of earth from shore end; sinking of cribs not properly balanced with stone; material consisting of short timber not properly bolted, and settlement of cribs to hard pan— after stone has been inserted. “ Piles have been driven through and outside of crib to prevent sagging outwards with success. Unskilled labor employed and inferior timber used.” The Hudson River Railroad Company on their work at Sixty- fifth street, North river, constructed during the summer a “tram¬ way” on piles on a 2° curve, across the westerly end of “bayou,” between Sixty-fourth and Sixty-third streets, North river. Previous to the construction of this “ tramway ” a great deal of dredged mate¬ rial, amounting to between fifty and sixty thousand cubic yards had been taken from the new bulkhead line, and deposited in the easterly end of the “ bayou.” The piles which formed the substructure of the “ tramway,” had been driven down to rock, having but little holding mud, but deemed by the engineer in charge sufficiently stable to serve all the purposes for which the tramway was intended. * Immediately after making earth. t A block 700 feet long deviated from original line to such a degree that piles had to be driven in front. $ Company are driving piles in rear. 49 The earlier part of this month the mud deposited in the rear slid with such a force as to carry away piles, lumber track, and a plat¬ form erected in the rear, making a total wreck of everything; the m mu d that had caused the disaster reappearing some fifty yards to the west of where the tramway stood, and showing about 2 feet above mean low water. In May last I instructed Mr. Staats, Surveyor, to ascertain the position of the bulkhead placed by the Hudson River Railroad Company, opposite to their grounds on the Hudson river at the foot of Sixtieth street, with reference to the established bulkhead line of the Department, and he reported to me as follows: “ I find that the bulkhead just north of the northerly line of Sixtieth street, is now four feet seven inches west of the west bulkhead line; and at a point opposite the centre line of Sixty-first street, it is about fourteen feet west of department line. This difference is due to the manner in which the crib-work has been forced out or bulged, the versed sine at point of greatest curvature being nearly eleven feet.” The crib placed on the bulkhead line by the Hudson River Rail¬ road Company is composed of dock logs, filled in with rubble, and at its base is forty-five feet wide; to mean low water it is forty-two feet six inches high ; from this point to the level of the coping, twelve feet six inches, it is composed of square timber. The whole height from its base being fifty feet; the width at top thirty feet. These facts establish conclusively that no structure, save and except a wall formed of either natural or artificial stone, properly founded on piles, has the capacity requisite to resist the lateral pres¬ sure to which it is subjected; and the wall already finished at Chris¬ topher street section having demonstrated that it possesses all the elements requisite for the solution of the problem, naught remains, except in future portions of the wall yet to be constructed, to reduce the mass of the material to the lowest practicable limit, to substitute “ beton en masse ” for manufactured blocks, and rubble facing with granite cope for the cut-granite facing heretofore used. After the trench for the wall on this section had been completed, and three hundred feet of the wall erected, at ebb tide, a very per¬ ceptible current was developed, where hitherto slack water had pre¬ vailed, thus proving that when the wall is continuously built, and the open system of piers substituted for the block and bridge piers now ex¬ isting, sufficient current will be created to sweep all sewerage matter toward the sea. This process will be rendered still more certain, how¬ ever, if the sewer outlets are carried to the end of the piers, as is the ultimate intention when the Department of Works completes the new sewers rendered necessary by the widening of the river street. In anticipation of this last mentioned improvement, the Department of Docks should adopt some process for the thorough preservation of 4 50 the new timber piers, as simultaneously with the restoration of clear limpid water the teredo navalis will reappear. The creation of this current is likewise an assurance that the widening of West street, from a varying width of from seventy to one . ^ hundred feet, to a uniform width of two hundred and fifty feet, bounded as it will be by an unbroken masonry bulkhead line, with open-pile piers projecting therefrom, will increase rather than decrease the cross section of the Hudson, as was feared by many advocates of the improvement when it was first suggested. All the beton blocks used at this section were manufactured at the Gansevoort street yard, under the supervision of Gen¬ eral Schuyler Hamilton, who likewise tested all the cement of which they were composed. The cement was the English Portland, of the brands of White Bros., and Knight, Bevans, and Sturge. The blocks were made on platforms in moulds, and generally remained at the yard for some months after they were completed, but in some few instances, when the work was being hurried, were transported to the points required and placed in position within ten days after they were finished. Canal Street and Other Sections. Since this report was written the Canal street section has been extended about two hundred feet, the short section at the foot of King street completed, and a new section commenced at the foot of Clarkson street. The plan of construction being in every case pre¬ cisely similar, except on the Clarkson street section, where it has been deemed advisable, in consequence of the great depth and soft¬ ness of the mud, to drive the two front rows of piles with a batir of one and three-fourth inches, instead of perpendicularly as on the other sections ; the object of the change being to oppose still greater resistance on the part of the foundation to lateral pressure, and to enable the mould-boards to be slid down further, so that the concrete may bind the pile-heads to a greater depth. On all these sections the cut-granite facing is adhered to, a large quantity of dressed granite being on hand in the Seventeenth street yard. It is probable, however, that when this stock is exhausted on sections yet to be constructed, the facing will be composed of rubble blocks made in the Department yards, and transferred by scows to the desired points and set by the ten-ton derrick. On the King street section the concrete was mixed on board of scows and placed within the caisson by means of the ten-ton derrick, the bucket used having a capacity of two cubic yards. 5i The advantages of the beton en masse system are: First .—As many sections as the Department deem advisable can be in course of construction at any one time, the distance between the old piers enabling the work to be prosecuted in the slips without any serious hindrance to commerce. Second .—The work by the adoption of the heating process as applied to water, sand, and stone, may be prosecuted, at least, during nine months out of the twelve. Third .—Unskilled labor can replace to a very great extent the skilled labor required under the block system. Fourth .—The huge and expensive one-hundred-ton derrick can be dispensed with, and small scow derricks employed for lowering the concrete, and the ten-ton derrick for placing the granite masonry, and eventually the manufactured rubble blocks. Fifth .—After the various sections of the wall in the slips are sufficiently advanced, by means of temporary approaches they can be connected with the old piers, thus allowing these old piers to be cut away on the line of the wall for the purpose of joining the adjacent sections. The outer ends of the old piers can be used as long as desirable. Sixth .—The new piers being differently spaced from the old, these new piers may be projected from the new bulkhead wall and com¬ pleted in a great many instances, before it becomes necessary to remove the old ones. Seventh .—The rapidity with which the work may be prosecuted, and the immense saving in its cost. .