in the laying of the sewer, and shall be completed and the excavation closed as expeditiously as possible.

ART. 54. BACK-FILLING AND CLEANING UP.

Paragraph 25. a. Back-filling.-In back-filling sewertrenches loose, fine earth, free from stones, shall be used up to a point 2 feet above the sewer, and shall be thoroughly compacted in 6-inch layers with hand-rammers. The remainder of the trench shall contain not more than broken rock, and no stone of this shall weigh more than 50 pounds. If necessary to meet this requirement the contractor shall supply suitable material for back-filling. The filling of the trench above the level of 2 feet above the sewer shall be rammed in 9-inch layers, or, when directed by the engineer, the trenches shall be water-tamped. Water-tamping shall be done in each case as directed by the engineer. All back-filling shall be done by hand and in no case shall scrapers or ploughs be used. In back-filling of tunnels or under railroad tracks especial care shall be taken to thoroughly compact the material. (The question of back-filling is a very troublesome one. In most soils, when the diameter of the sewer does not exceed one sixth of the depth of the trench, all the earth excavated can be returned without leaving any ridge and without any appreciable after-settlement. But this can be done only at considerable expense-from 4 to 12 cents for each cubic yard of back-filling-by careful ramming or water-tamping; in tough clay no way has yet been found to accomplish this. When the trench is through fields or unpaved streets this extra payment is not generally warranted by the benefits derived; but through paved streets it generally is. The above specifications are similar to those ordinarily used, but contractors generally understand that they will not be enforced except in well-paved streets, and bid accordingly. It is preferable to leave the option

confessedly with the engineer as to whether the trench shall be tamped, and pay for the tamping which is ordered, having it well done. The following specification is offered as a substitute, to be rigidly enforced.)

Paragraph 25. b. Back-filling.-In back-filling sewertrenches loose, fine earth, free from stones, shall be used up to a point 2 feet above the sewer, and shall be thoroughly compacted in 4-inch layers by hand-rammers, there being two rammers to each shoveller. Rammers for this purpose shall weigh from 4 to 6 pounds each, and have not to exceed 10 square inches of face. The remainder of the trench shall contain not more than one third broken rock, and no stone of this shall weigh more than 50 pounds. If necessary to meet this requirement the contractor shall supply suitable material for back-filling. Unless otherwise specified the trench above the level of 2 feet above the sewer shall be filled by hand with this material up to within 1 foot of the surface, and the remainder of the filling shall be made of fine material containing no stone having any dimension greater than 2 inches. The filling shall be crowned above the trench, having a height above the street surface of twice as many inches as the top width of the trench in feet, and neatly rounded off, the paving material previously removed, if any, being spread evenly over the top. After refilling, and for 6 months after the completion of this contract, the contractor shall from time to time refill any settlements which may occur, constantly maintaining the trench in a neat and safe condition, and deliver it over in that condition at the end of that time. Hand-ramming or water-tamping shall be used where directed, and as follows, an additional sum being paid therefor according to the price. bid.

For hand-ramming the earth shall be spread by shovels in 4-inch horizontal layers and solidly compacted with rammers weighing from 6 to 8 pounds and having a face of not to

exceed 20 square inches. There shall be two rammers to every shoveller, and the former shall be of at least as great strength and efficiency as the latter. The paving shall be restored in as good condition as found, being given a crown of inch over the trench, but not, in the case of macadam or gravel paving, overlapping the old paving. During backfilling no sheathing which is to be drawn shall at any time extend into earth which is being rammed, but it shall be drawn so as to be always above it, if it cannot be at once entirely removed.

This

For water-tamping the earth shall be levelled off in horizontal layers 2 feet thick and flooded with water until, after standing for 5 minutes, water shall just show on the surface, when another layer shall be thrown in and flooded. shall be continued up to within 2 feet of the surface and allowed to stand for a few hours. The last 2 feet shall then be put in and hand-rammed as specified above, and the paving relaid.

No water shall be turned into the trench until all cementwork in sewers and appurtenances shall have had full time to

set.

If a trench is rammed or water-tamped any earth which may have slipped or caved from the bank shall be thrown out of the trench and the space refilled and tamped in the same way as the trench proper, without extra compensation.

Paragraph 26. Street Surfaces. In all paved, macadamized, or improved streets generally the surface of the trenches shall be finished without needless delay, in the most workmanlike manner, with the same kind of roadway improvement that was removed in excavating the trench, and so that the underlying courses, as well as the finished surface, shall conform to the remainder of the roadway, and shall in every respect be equal in quality, character, materials, and workmanship to the street improvement existing over the line

of the trench immediately previous to making the excavation. The expense of restoring the pavement or improvement must be included in the price per lineal foot of sewer.

Paragraph 27. Cleaning up.-As soon as the trench has been refilled and paving replaced all stones, plank, or other refuse material of whatever description deposited and left by the contractor on the streets shall be removed therefrom and the said streets restored in all respects to the same condition as before the trenching was commenced. All surplus earth which may be left on the street after the trenches have been refilled as specified above shall be regarded as the property of the contractor, and must be removed as soon as possible at his expense.

Paragraph 28. Final Inspection.-Upon notification by the contractor of the completion of the work herein contracted for the engineer will carefully inspect all sewers, appurtenances, and all other work done by the contractor. In each stretch of pipe sewer intended to be straight light shall be visible from one end to the other. Any broken or cracked pipe shall be replaced with sound ones. The interior of brick sewers shall be of the required shape and dimensions, sound and of a uniform surface. Any deposits found in the sewers, protruding cement or packing, shall be removed and the sewerbore left clean and free through its entire length. There shall be no appreciable amount of leakage into any stretch of sewer. All underdrains shall discharge water freely and give evidence of having a clean and open bore. All manholes, lamp-holes, and other appurtenances shall be of the specified size and form and of a neat appearance, and their tops shall be set to the proper grade. In general the work shall comply with these specifications, and if found not to do so in any respect shall be brought to the proper condition by cleaning, pointing, or, if necessary, excavating, and rebuilding, all at the expense of the contractor. But if it be found after

uncovering any pipe or other work at the order of the engineer that no defect exists, or that the defect was not due to any fault of the contractor, then the expense of this shall be borne by the city.

ART. 55. GENERAL PROVISIONS, PAYMENTS, ETC.

Paragraph 29. General Provisions.-If any alterations in plan directed by the engineer diminish the quantity of work to be done they shall not constitute a claim for damages nor for anticipated profits, and any increase or decrease shall be paid for or deducted according to the quantity actually done, and at the price established for such work under this

contract.

The work shall be prosecuted in such manner and from as many different points, at such times and with such force as the engineer may, from time to time during the progress of the work, determine.

The contractor will be furnished with a set of drawings showing the details and dimensions necessary to carry out the work, dimensions in figures thereon having precedence over the scale. These plans and a copy of these specifications are to be kept constantly at the work by the contractor or his authorized foreman. The plans submitted to contractors for proposals are to be interpreted in conjunction with the specifications, and descriptions of the character of the work appearing on the plans are made a part of these specifications. No deviations from the drawings will be allowed without the direction of the engineer to that effect.

Should it be necessary at any time to move monumentstones or other permanent records the contractor shall not disturb them until given permission by the engineer.

The contractor shall provide suitable stakes, plank, and forms, and render such assistance to the engineer, at his own