(After stating the foregoing facts.)
The deposit by plaintiffs with the board of drainage commissioners of their check was to insure the execution of a bond by the contractors for the faithful performance of such contract as might be entered into between these parties for this work in accordance with the terms of the drainage act. Acts 1911, pp. 108, 120; 1 Park’s Code, § 439(u). The board of drainage commissioners would not be authorized to collect the check, and appropriate the proceeds to the use and benefit of the drainage district, unless the board accepted the competitive bid of plaintiffs, and the latter had refused to execute a contract in accordance with the terms of their bid, or after executing such contract had failed to give bond for the faithful performance of their contract. Without acceptance of their bid, and their refusal to make a contract in accordance with its terms and in compliance with this law, and their failure to execute a bond for its faithful performance, there could be no forfeiture of their check; and the drainage board could not collect it and appropriate its proceeds.
The drainage act of 1911 (Acts 1911, pp. 108, 114; 1 Park’s Code, § 439 (i)) provides, that, after a drainage district is established, the drainage court shall refer the report of the engineer and viewers back to them to make a complete survey, plans, and specifications for drains, levies, or other improvements. After a complete survey, plans, and specifications for the work are made, the board are required to give notice “for two consecutive weeks in some newspaper published in the county wherein such improvement is located, if such there be, and such additional publication elsewhere as they may deem expedient, of the time and place of letting the work of construction of said improvement, and in such *296notice they shall specify the approximate amount of work to be done and the time fixed for the completion thereof.” On the day appointed for the letting of the work the commissioners and the superintendent of construction shall “let to the lowest responsible bidder, either as a whole or in sections, as they may deem most advantageous for the district, the proposed work. No, bid shall be entertained that exceeds the estimated costs, except for good and satisfactory reasons it shall be shown that the original estimate was erroneous. They shall have the right to reject all bids and advertise again the work, if in their judgment the interest of the district will be subserved by doing so. The successful bidder shall be required to enter into a contract with the board of drainage commissioners and to execute a bond for the faithful performance of such contract, with sufficient sureties, in favor of the board of drainage commissioners for the use and benefit of the levee or drainage district, in an amount equal to twenty-five per centum of the estimated cost of the work awarded him.” Acts 1911, pp. 108, 120, 1 Park’s Code, § 439 (u).
Bidders make their bids based upon the complete survey, plans, and specifications called for by the above provision of the act. Bids thus made are to be accepted or rejected by the commissioners and the superintendent of construction. After the commissioners advertise for .such bids and bids are made, the commissioners cannot reject all bids and materially alter the terms of a bid, and, after making such alteration, enter into a contract with one of the bidders for the construction of the proposed improvement. The commissioners cannot make changes in the plans and specifications of the proposed project which in substantial respects vary its character and materially affect its cost; and they cannot, without further advertising, lawfully accept new proposals for such construction and award a contract therefor. In Manly Building Co. v. Newton, 114 Ga. 245 (40 S. E. 274), this court, in dealing with a contract let for the erection of a court-house, said: “When an ordinary advertises for sealed proposals for the erection of a court-house, and, after receiving, considering, and rejecting all such as are presented to him, makes changes in the plans and specifications of the proposed building, which in substantial respects vary its character and materially affect its cost, he cannot, without further advertising, lawfully accept new pro*297posáis for the construction of tbe building, and award a contract therefor.” The principle ruled in that case is applicable to lettings contracts under the drainage act for the purpose of constructing drainage projects. Plaintiffs, in response to the advertisement of the commissioners inviting bids for this work, submitted a bid in which they proposed to do this work for $80,000, in accordance with the plans and specifications prepared by the engineer and viewers. They afterwards modified their bid by proposing to do the work for $70,000 in view of certain changes made in the plans and specifications, upon the condition that the board would not require them to give a security bond, but would accept from them a bond, secured by their mortgage upon the two boats which they would use in doing said work, conditioned for the faithful performance of their contract. Thereupon the board passed a resolution authorizing its chairman to enter into a tentative contract with the plaintiffs for the construction of the proposed work, based upon their modified bid, and permitting plaintiffs to give their bond, secured by a mortgage on said boats, conditioned for the faithful performance of their contract, instead of a bond with surety, and further providing that a formal contract in more detail would be executed when proper changes had been made by the civil engineer in the plans and specifications of said work; and that plaintiffs should furnish a bond in the sum of $17,500, secured by a mortgage on said boats, conditioned for the faithful performance of such formal and fuller contract. This resolution further provided that the certified check for $1000 deposited with the board by plaintiffs was to be held by the board until said mortgage bond was furnished by plaintiffs. In pursuance of this resolution, plaintiffs entered into a tentative contract for the doing of said work, which is set out in full in the statement of facts. Under these circumstances the tentative contract let by the commissioners for draining this district was illegal and void, as the commissioners were without competent authority to make it in the manner in which it was executed. Bird v. Franklin, 151 Ga. 4 (5b) (105 S. E. 834). The plaintiffs could not be required to execute a bond for the faithful performance of an illegal and void contract. Bidders are only required to give bonds for the faithful performance of contracts for the construction of these drainage districts, based upon competitive bids and *298executed in terms of this statute. There is no provision of law which authorizes the commissioners to let contracts based on non-competitive or modified bids; and contracts which are so let are unenforceable. This being so, the plaintiffs did not forfeit their check by failing to give their bond, secured by mortgage on certain boats to be used by them in draining the lands of this district, for the faithful performance of this tentative contract.
The commissioners were not authorized to make material changes in the survey, plans, and specifications for this improvement, and then contract with plaintiffs for this improvement, based on said changes, without readvertising for bids, by reason of the provision in the specifications that the “engineer may at any time make any changes in the location, form, dimensions, grade, slopes, or excavation and- embankments, the depths or widths of the ditches, or other work, and may make variations in quantities of work to be done, either before commencement of the work or during its progress, without thereby altering or invalidating any of the ratios of pay therein named, or this contract in any other respect, provided such changes shall not increase or reduce the total contract price more than 15%, or materially change the general character of the work, so as to make necessary the installation of different equipment.” This provision refers to changes which can be made after contracts for these improvements have been made, and not to alterations in the work which can be made before such contracts are let upon competitive bids. Otherwise it would be in the power of the commissioners to effectively destroy all competitive bidding for the construction of these improvements. Under the above resolution of the commissioners, the plaintiffs’ check was only to be held by the board until said mortgage bond was given, and this mortgage bond was only to be furnished upon the execution of a formal contract in more detail, executed after proper changes had been made by the engineer in the plans and specifications of the work. Until the terms and details of this formal contract had been agreed upon, and the formal contract executed, the plaintiffs were under no obligation to execute their mortgage bond. In the absence of the making of such contract, their check could not be forfeited. The check could not be cashed until the formal contract, with all its terms agreed to, had been executed and awarded to the plaintiffs.
*299As we have seen, “the successful bidder shall be required to enter into a contract with the board of drainage commissioners and to execute a bond for the faithful performance of such contract.” Acts 1911, pp. 108, 120, 1 Park’s Code, §439(u). Under this law there must be a final, valid, and enforceable contract before the successful bidder is required to give this bond. If there is no such contract, no bond can be required. The parties executed an instrument which was not a final and binding contract. It expressly declares that it is only a tentative contract, that a contract in proper and legal form and more in detail is to be executed, and then only after changes have been made by the engineer, and a legal order has been obtained from the drainage court authorizing the same. This instrument amounts to nothing more than negotiations looking to a final and binding contract. To be final an agreement must comprise all the terms which the parties intend to introduce in it. Mackay v. Tide Water Oil Co., 158 N. Y. Supp. 667 (94 Misc. 694); Sherry v. Proal, 131 App. Div. 774 (116 N. Y. Supp. 234); 13 C. J. 289, § 100; Id. 303, § 124. Where it is evident from a written instrument, that the parties contemplated that it was incomplete, and that a binding agreement would be made subsequently, there is no agreement. Hawkworth v. Durant, 156 N. Y. Supp. 1026 (93 Misc. 149); Petze v. Morse Co., 125 App. Div. 267 (109 N. Y. Supp. 328), affirmed, 195 N. Y. 584 (89 N. E. 1110); Mayer v. McCreery, 119 N. Y. 434 (23 N. E. 1045). This tentative contract was a memorandum of some of the terms which were to go into the formal contract, which was not to be executed until the engineer had made certain changes in the specifications for the work, and an order bad been obtained from the drainage court authorizing the contract; and such tentative agreement did not amount to a binding one. Until a contract in proper and legal form and more in detail was executed, after such changes had been made, and after such order had been obtained, there was no contract; and as there was no contract, no bond could be required of the plaintiffs for its performance. As no bond could be required of the plaintiffs, there could be no forfeiture of their check.
Under the above rulings a verdict was demanded in favor of the plaintiffs. This being so, it becomes unnecessary for us to consider the assignments of error on instructions given by the *300court to the jury, and on the refusal of the trial judge to rule out certain evidence.
Judgment affirmed.
All the Justices concur.