essential to fair and intelligent treatment of the bidders themselves, and so necessary in order to determine which is really the lowest bid, that the practice of preparing and supplying such blank forms of proposals should always be followed.

65. Manner of Letting the Work. Before such forms can be prepared, however, several questions must be decided, among which are the following:

I. Shall the work be let as a whole, or shall it be let in parts.

2.

Whether let as a whole or in parts, shall bids be received for fixed sums for the whole or for the several parts, or shall they be received on a basis of certain suitable units of measurement. As, for instance, per cubic yard, as for earth work, per perch for masonry, per pound for iron work, per square yard for street paving, per mile for railroad rails and ties, or per lineal foot for water pipe or sewers, etc.

3. Shall the work be let in such a way as to involve the payment of a bonus or additional sum for the performance above that required, and a corresponding reduction in price for a failure to meet the requirements.

4. Shall the work be let for a certain price for the original construction, and a certain price per annum for maintenance. for a given period.

5. Shall the contractor be required to furnish all materials and perform all the labor, or shall the principal purchase a portion or all of the material and turn it over to the contractor for use in the construction of the work.

66.

Some

Contract Let as a Whole or in Parts. of the considerations in favor of letting work as a whole rather than in parts are:

(a) By this means one man or company alone is responsible for the faithful performance of the work both as to quality and as to time. This prevents a division of responsibility

which is always bad, and in the case of carrying out contract work is often the cause of failure to have the work completed within the time specified, without being able to locate the responsibility for such delay. Where there are several contractors upon the same piece of work, each may so stand in the way of another that the work may be greatly delayed, and yet each one of the several contractors may have a reasonable defense which would shield him from personal liability.

(6) When there is but a single contractor the business is concentrated so that the work of the engineer or of the inspectors is greatly lessened from having to deal with one man instead of many separate contractors.

(c) When several contractors are engaged upon the same work it is difficult for them so to plan their parts, in time, as to avoid a certain amount of delay where the work of one is dependent upon antecedent work of another. When the work is done by a single contractor he can arrange to avoid such delays as are almost necessarily incident to the working of several contractors in sequence.

(d) When the work is such as is commonly let in a single contract, or in other words, when bids can be received from parties who have been accustomed to carry out all parts of such a work, it is usually more economical to let the work in a single contract than it is to let it in parts. In the former case there is but one man to reap a profit from the construction, whereas if let in parts, each contractor must, of course, make his estimate in such a way as to allow himself a reasonable profit.

Some of the arguments in favor of letting the work in parts are:

(a) The project may involve constructions of such different kinds as to make it impracticable for one contractor to undertake the entire work. In this case the letting in parts is necessary to a skillful performance.

(b) Where there are local parties who are competent to execute portions of the work, but not the whole, and who are anxious to bid upon such portion, it may be wise to let the work in parts provided it is reasonably certain that competitive bids can be received on all the parts. Even in this case it is desirable also to receive bids upon the whole work, so that when the bids are opened it will appear which is the more economical method of letting. Even when it is reasonably certain in advance that the contract will be let as a whole it is often wise to receive bids on the parts in order to satisfy local demands, and to avoid invidious criticism and public detraction. This is especially true in the case of public works, if the local bidders who wish to submit proposals on parts of the work, but who would be incompetent to bid upon the whole, are shut out by receiving bids only upon the entire project.

67. Contract Let for a Fixed Sum or per Specifiled Units. When the work to be performed under a contract is perfectly definite as to quantity, it is best to let the contract for a fixed sum. When either the quantity of work to be done or the quality or kind of material to be encountered, as in excavations, is more or less unknown and indeterminate, it is necessary to let such parts of the work at least, in terms of some suitable unit of measurement. Thus in the case of excavation, the kind of material which will be encountered is always more or less uncertain, and the quantities to be moved are usually undetermined in advance. In various other lines of work, also, the exact quantities are not measured or computed in advance of the construction, so that in all such cases it is necessary to let the work per unit of measure. It is often wise, however, to assume a certain definite amount of work of each kind to be performed, and let the contract for a fixed sum on the basis of this assumption, providing for variations from these amounts in the blank form of proposal by requiring the bidder to state not only a fixed sum for the assumed total, but

also a price per unit of measure, in accordance with which the quantities assumed as the basis of the bid may be either increased or diminished, it being understood, however, that the quantity stated is approximately the amount of work to be performed. In this way it becomes known in advance about what the work is to cost, and if the quantities are changed somewhat these changes do not become a source of contention between the parties.

In choosing the units of measure which shall serve as the items to which prices are to be affixed by the bidders, it is necessary to select and describe these units in such a way that they can not be misunderstood; thus in masonry it is better to use the cubic yard as a unit rather than the perch, since this latter has different values in different localities. Also it should be clearly defined in the proposal itself in what way these measurements should be taken, as, for instance, in masonry, whether all openings should be excluded, and in tunnel excavation that the measurement should include only the material excavated inside the given sectional boundaries, and in water pipe on which bids are received per foot in length for the various sizes, that the measurements should be taken on the center lines of such pipes, after they are laid, etc. Also in the case of the furnishing of materials, machinery, and appliances, the printed proposal should indicate where the material is to be delivered and whether or not the machinery is to be erected. The failure to make the proposal clear in these and other minor particulars is often the cause of serious disagreements, provoking delays, and sometimes of considerable expense.

68. Contract Involving a Specific Performance. When machinery is purchased on the basis of a specific performance, as in the case of pumping engines, steam boilers, steam ships, and the like, where a specific performance is made the basis of the contract price, it is customary and proper to provide for specific additional sums for stated percentages of

excess of performance over and above that which forms the basis of the bid, and also for stated deductions from the contract price for given percentages by which the performance fails to meet the standard. In this way the contractor is fairly paid for accomplishing more than he agreed to, and the purchaser obtains a fair reduction in price for any failure to reach the agreed standard. When a specific performance is made the basis of a contract without these agreed premiums and discounts, the purchaser is at liberty to refuse to accept the work at any price, in case of even a partial failure to meet the specified requirements; while, on the other hand, if the contractor has far exceeded the specifications, he gets no benefit whatever for the enhanced value of the product. A specific performance, therefore, when made the basis of the acceptance of a piece of contract work without these provisions for premiums and discounts is a very onesided and unfair contract, and its use should be discouraged by engineers.

In all cases where a specific performance is made the basis of a contract price, the conditions of this performance should be so clearly stated in the specifications, and the nature of the tests to determine this performance so distinctly described that no misunderstanding could arise when the time comes for making these tests. These descriptions belong in the specifications rather than to the proposals.

69. Contract Including Maintenance. In the case of street pavements, especially where the material is new or untried, it is common to require the contractor to maintain it for a given period, at a stated price per annum. In this case this maintenance price must also be provided for in the proposal, as well as the price charged for first cost.

70. Contract for the Work Only. It is often wise for the principal to purchase materials himself which shall be