Over culverts and behind bridge abutments the embankments shall be formed carefully, so as to avoid damage to, or bulging of, the masonry. Only the best materials will be used for this purpose, the same to be deposited in layers of not over ten inches thick. The contractor to be responsible for any damage to the masonry.

Contractors, when directed by the engineer in charge of the work, will deposit on the side of the road, or at such convenient point as may be designated, any stone or rock that they may excavate; and if, in so doing, they should deposit material required for bank, the additional cost, if any, of procuring other materials from without the road will be allowed. All stone or rock excavated and deposited as above will be considered the property of the railroad company, and the contractors upon the respective sections will be responsible for its safe keeping until removed by said company, or until the work is finished.

The line of road, or the gradients, may be changed if the engineer shall consider such change necessary or expedient; and for any considerable alterations, the injury or advantage to the contractor will be estimated, and such allowance or deduction made in the prices as the engineer may deem just and equitable; but no claim for an increase in prices of excavation or embankment on the part of the contractor will be allowed or considered, unless made in writing before the work in that part of the section where the alteration has been made shall have been commenced. The engineer may also, on the conditions last recited, increase or diminish the length of any section for the purpose of equalizing or balancing the excavations and embankments.

Whenever the route of the railroad is traversed by public or private roads, commodious passing places must be kept open and in safe condition for use; and in passing through farms the contractor must also keep up such temporary fences as will be necessary for the preservation of the crops.

The above specification makes no provision for what is commonly called "haul." By "haul" is meant an additional compensation for carrying the excavated material beyond a certain limiting distance. Such a provision usually accompanies a specification for excavation, and may be given in the following language:

The price paid for "excavation" in all the several classes thereof will be understood to cover and pay for the entire expense of its removal by any method whatever, including loading, unloading, transportation and deposit in the manner prescribed in these specifications, in the places designated by

the engineer, provided the haul of the material so transported does not exceed () feet, and beyond that distance per cubic yard per one hundred (100) feet will be allowed and paid, for such extra haul, in addition to the price paid for excavation.

122. Excavations Under Water. Excavations made under water are usually for the purpose of securing a channel for the passage of boats. In many cases the character of the material is quite various, and largely unknown. It is proper for the engineer to make such investigations as are practicable to discover what these materials are, and to about what depth the cutting will have to be made, and to give the contractor the benefit of such information. It would not be well for him, however, to make positive statements as to the character of the material, and he should relieve himself in the specifications of all responsibility for the information given. The contractor on the other hand should inform himself of the nature of the work so far as possible, both by personal examination, and by availing himself of the investigations of the engineering department. The following paragraphs concerning excavations under water are taken from the standard specifications used by Col. O. M. Poe, of the corps of engineers, U. S. army.

All available information in the possession of the United States will be given upon application. The United States will not guarantee the correctness of its information and will not be responsible for the safety of the employees, plant or materials used by the contractor, nor for any damage done by or to them from any source or any cause. Bidders are expected to satisfy themselves as to the nature of the work to be done, and it will be assumed that proposals are based upon a thorough understanding of its character. Intending bidders are urged to visit the localities of the work, and, by personal inspection and inquiry, fully inform themselves as to the present and probable future conditions. Navigation shall not be obstructed, and no allowance or concession will be made for any lack of information on the part of the contractor regarding the work. price bid shall be full compensation for furnishing all necessary labor, materials, and appliances of every description, and for doing all work herein specified to the satisfaction of the engi

The

neer officer in charge, and shall include all risks and delays of whatever nature attending the execution of the work.

The work comprises the improvement of two shoals in St. Mary's River, Michigan, above the canal. The upper shoal lies northwesterly, and the lower shoal northeasterly from old Round Island Light House.

The work to be done consists in excavating a channel within the side and end lines prescribed by the U. S. Agent in charge, said channel to have a bottom width of 300 feet, and a total length of about 3,000 feet, the estimated excavation being 90,000 cubic yards, bank measure, more or less. The greatest distance to the dumping ground will not exceed two miles, and the average distance will not exceed one mile.

The material to be removed consists of boulders, clay, sand, gravel, and possibly hard pan, all in unknown proportions.*

The bottom of the completed cut shall be in a plane 25.32 feet below the upper surface of the coping of the lock of 1881 in St. Mary's Falls Canal, the face of excavation probably varying from scraping to 5 feet.

No payment will be made for excavation below 22 feet depth of water. All excavations within the specified side slopes and between 21 and 22 feet depth of water will be paid for at half rates in the final estimates.

Proposals will be received for bank measure only. For the monthly estimates 30 per cent. will be deducted from scow measurements, but the total of the estimates made for the upper shoal will never exceed the total of the estimates made for the lower shoal, until all the required excavation has been finished at one of the shoals, and an equal amount of excavation has been done at the other.† O. M. P.

*In letting this work all materials were entered in one class, even though it were solid rock. In this particular instance no solid rock was anticipated, and hence it is not mentioned in the list of materials to be encountered, but in other sections solid rock was anticipated, and was so entered in the list of materials, but the proportion in each class was left for the contractor to estimate as best he could from the investigations made by the engineering department, and such additional borings as he might make himself, there still being but one price per cubic yard for all materials. The responsibility of the contractor in this connection is fully defined, however, in the extract given above.

†This work was let by the cubic yard as measured in bank. That is from soundings taken both before and after the excavation between the side lines indicated, and above the depth of a1 feet. Material excavated below the depth of a feet and above the depth of 22 feet was paid for at half rates. Any excavation below the depth of 22 feet was not paid for at all. Neither were the excavations made outside the side boundaries. In other words the material was paid for in cut as it would be described in earthwork out of water. The reason for requiring the work on one shoal to be fully completed before an equivalent sum is paid for the other is to insure the completion of the work. If a small amount of material had been left above the 21 foot line in various places, the excavation of these scattered portions would be very expensive per cubic yard, and if the contractor had already received the major part of his compensation it might be difficult to induce him to finish up the work properly.

123. Specifications for Measuring Quantities Excavated Under Water by Weight and Displacement. The following specification is taken from the U. S. Engineer Corps specifications for excavation in the James River, and they illustrate another method of determining amount of material excavated. In this case the soundings in the river are only used for determining when the excavation has been completed to the proper depth, and to prevent excavation beyond a limit of over-depth.

CLASSIFICATION.-Mud, sand, clay, and gravel, under the class "earth excavation," will include those materials, however hard or compact they may be, the gravel to include pebbles up to three inches in diameter. "Cobble" will include stones up to three cubic feet. "Soft Rock" will include any rock in place which can be removed by dredges without blasting, although, for economy in removal, blasting is resorted to, and will include the disintegrated rock found for two or three miles below Richmond. "Solid Rock" will include rock which rings under the hammer, boulders measuring over three cubic feet, and other rock which, in the opinion of the Engineer officer in charge, can not be removed without blasting. When soft and solid rock occur together, in strata or otherwise, the amount of each will be ascertained by the inspector after the material is placed on lighters. Mixed classes of material must be separated by the contractor, at his expense, for measurement by displacement as the lighters are unloaded at the place of deposit.

UNCLASSIFIED ROCK.-In place of bidding on soft and solid rock separately, an alternate bid may be submitted for unclassified rock, which will include all material described in these specifications as rock, whether soft or solid. The bid will be for the ton of 2,000 pounds, and the weight will be ascertained by displacement, as hereinafter described. The bidder on this class will specify a price for extra haul per ton of 2,000 pounds.

Should the bid for unclassified rock be accepted on any section, the price per ton will be stated in the contract in lieu of those for soft and solid rock. On such section the contractor must begin the excavation of areas known to be of solid rock in part, with other areas, as directed by the Engineer, and continue their excavation, or accept an equivalent reservation in tons, according to the relative cost of excavating soft and solid rock, to be determined by the Engineer, until such solid rock excavation is made.

MEASUREMENT OF EXCAVATION.-All materials excavated in the two and a half miles below Richmond and at Drewry Bluff will be measured on deck lighters by displacement of water taken at 62 pounds per cubic foot. The basis of measurement for "solid rock" will be 155 pounds and of soft rock 120 pounds, and of other classes 120 pounds per cubic foot, until otherwise ascertained at the instance of either the Engineer or the contractor. These "other classes" will then be loaded on deck lighters (with gauges attached) whose cubic feet of submergence has been ascertained for each tenth of a foot. The load will be put on in shape suitable for accurate measurement by cross sections, at the expense of the contractor, and in such manner that the plane of submergence will be parallel to the deck of the lighter, as near as may be. The difference in cubic feet of submerged section, light and loaded, at 62 pounds to the cubic foot, will be considered the weight of the measured load. The lighters must be kept bailed out, and will be considered loaded with the same weight when afterward sunk to the same gauge readings. The proportion of a partial to a full load will be determined by the ratio of the displaced volumes of water.

The Engineer may measure the displacement of empty lighters at his discretion, and the contractor must free them from water at his own expense whenever requested by the inspector for the purpose of determining their loads.

DUMPING LIGHTERS will not be allowed in transporting materials excavated at Drewry Bluff or above, but can be used for material excavated at Harrison's Bar and Goose Hill Flats. Where dumping lighters are used measurements will be made by the capacity of the pockets.

DECISION AS TO QUANTITIES.-The duty of determining the quantity of material carried in or on lighters will be performed by inspectors appointed by the Engineer in charge, and the decision of such inspectors, acting under the orders of the Engineer, as to the amount of material excavated and removed, as well as to its place and manner of deposit, shall be final and without appeal on the part of the contractor.

OVER-DEPTH.-No allowance will be made for dredging more than twelve inches below the required depth or outside the limits of the channel as marked by stakes or ranges, unless such additional depth is necessary to break up strata of rock or cemented earth. Increased depth will be allowed in such cases if authorized by the inspector, acting under the direction of the Engineer. If a deficiency in depth is found the contractor must re-excavate the bottom until the required depth is obtained.