I. At the trial plaintiff introduced the tax bill, proved the assignment and rested. Defendant demurred to the evidence on the ground of the insufficiency of the tax bill to make a prima-facie case. The demurrer was overruled. By section 24, acts of 1873, page 370, charter of Sedalia, it is provided that certified tax bills “ shall in all cases be prima-facie evidence that the work and material charged in such bill have been furnished, of the execution of the work, the rates or prices, amount thereof, and of the liability of the person therein named as the owner of the land charged with such bill to pay the same. ” One great fault with this tax bill is its failure to allege defendant to be the owner of the property sought to be charged, as required by the charter. It levies “against John Newton a special tax, ” but nowhere intimates him tobe the owner of the property. Besides this defect, the tax bill as a whole is liable to much adverse criticism, it should and can be amended. Kiley v. Cranor, 51 Mo. 541. There is no direct statement of the execution of the work, or who did it, or that material was furnished, or that the property sought to be charged was in this state. These *392things can be inferred from what is stated, but the better and safer way would be to make it more definite by amendment.
II. ' It is insisted that the ordinance under which this improvement was made is void, in that it does not itself provide for the mode, material or character of the work, but refers to “specifications in the hands of the city engineer. ” The charter empowers the mayor and board of aldermen “to grade, pave, macadamize or otherwise improve” a street by ordinance only ; and it is well settled that they cannot delegate this power, or exercise it in any other way. But does it follow that the mode, material, or character of the work shall be specified in the ordinance itself ? We have cases in this state where an ordinance has been upheld which, though insufficient and incomplete in itself, refers to other ordinances theretofore enacted. Moran v. Lindell, 52 Mo. 229; Carlin v. Cavender, 56 Mo. 288. In State v. Mayor, 3 Vroom, 49, an ordinance declared that a street should ‘£ be laid out and opened as defined on the map filed in the office of the town clerk, and then finder a videlicet purports to state what that definition is, but makes the error stated” in that case. The ordinance was upheld notwithstanding the false description ; the reference to the map saved it. So in State v. Morristown, 5 Vroom, 445, an ordinance was held valid which referred for grade lines to maps and profiles on file in the office of the town clerk, and that though the map appeared not to have been filed, it was subject to identification by proof. To the same effect is Stone v. Cambridge, 6 Cush. 270. My conclusion is, that if the specifications were “in the hands of the city engineer” at the time the ordinance Avas adopted it was sufficient for all legal and practical purposes. The mayor and board of aldermen by ordinance adopted the specifications as they existed at the time in the official custody of the city engineer.
III. The contract as let by the committee is not the contract contemplated by the ordinance or the specifications. The specifications referred to in the ordinance *393called for a foundation of hard limestone four inches thick, laid close together, and no stone to be less than one foot square. While it is true the contract as let contained such a provision, it contained the further important provision permitting the substitution of other and different material, the utility of which seems from the testimony to be of much contrariety of opinion. It permitted the contractor, at the request of the property-owner, to substitute, in lieu of the limestone called for in the ordinance, “flint boulders or‘nigger heads’” at fifty cents less price per foot. The correctness of the proposition that the contract cannot differ, from the terms of the ordinance is evident. Thompson v. Schermerhorn, 2 Selden, 92. It has been held many times by the Supreme Court of this state that when authority is conferred upon the board of aldermen to improve streets it cannot be delegated to others, but that such board must exercise it strictly within the terms of the charter. Thompson v. City, 61 Mo. 282; Matthews v. City, 68 Mo. 119, and cases cited. It follows as alogical conclusion, that if the board of aldermen must prescribe the character and kind of improvement for a street, and that they cannot delegate this power, a contract for improvement, the terms of which have been prescribed by them, cannot be changed by the parties designated to let it.
It is, however, said by counsel that that portion of the contract not authorized by the ordinance may be rejected and there will yet remain a valid contract which is within the terms of the ordinance. But the difficulty with the application of this contention is, that this improvement was made under the portion which it is suggested to reject. If that is eliminated, then the labor was performed and the material furnished without a contract to support it.
Again, the contract as let is not such as was advertised for bidders, which of itself is enough to render it illegal. People v. Board, 43 N. Y. 227. The advertisement for bidders for this work was under the terms of *394the ordinance, while the contract, as actually let, was as has been shown. Notice of the letting of public work or improvements is for the purpose of competition and for safety against the occasional cupidity of public servants, as well, I might add, as for affording all an equal opportunity to obtain the employment the work affords. It is, and has been found to be, one of the means of security to the public and justice to the individual. A false notice, a notice hot in substantial accord with the fact, is as bad, if not worse, than none at all. This contract for boulders was let without notice or competition. uIt may-be that parties who had no facilities for furnishing limestone at any reasonable price, and, therefore, did not bid for the work, would have been eager to obtain the contract if they had known boulders were to be used. In some sections limestone would have to be quarried at much trouble and expense, while boulders could be gathered from the beds of creeks. This may or may not apply to the special vicinity of Se dalia, but it illustrates the necessity for caution where diverse interests should have an opportunity to be subserved. It is, however, contended that since the charter does not call for notice, none is required. But section two of the ordinance plainly implies there shall be notice. It directs that sealed proposals shall be received, and that the contract and work shall be let to the lowest responsible bidder. There can be no doubt that the private letting is in the face of this section, and that it contemplates reasonable public notice, if none other is prescribed by some general ordinance.
IY. Plaintiff interposes the plea of estoppel as a relief from the difficulties which lie in the way of his recovery. I am of the opinion there is no estoppel. The contract was different from the ordinance. The work was not done under the contract contemplated by the ordinance, it was done under the contract as changed. Admitting defendant said all that is claimed by the evidence, yet he was so speaking under the idea that there was a valid *395contract. Assuming both were ignorant of the invalidity of the contract, what has defendant done that he-should be estopped ? Anderson went to him, and, in-effect, said: “I have here a valid contract to pave the street in front of your property, it gives you a choice of limestone at $3.10, or boulders at $2.70 per foot, which will you take?” Defendant (laboring under the identical impression that Anderson is, as to the validity off the contract, but with different knowledge as to how it. was made) answers, “I will take boulders.” Anderson was unquestionably relying on his contract, and defendant neither did,nor said anything to mislead him. He - only acquiesced in Anderson’s own statement and answered the inquiry which Anderson made. If Anderson had been acting under a legal contract contemplated by the ordinance and defendant had induced him to-change the material therein called for, it would present an entirely different case.
We have not been referred to any case from this-state bearing on the question in the shape it is presented here. There is a class of cases which hold that mere knowledge that work is being done by a municipal corporation is sufficient to put the property-owner upon-inquiry as to the right of the corporation, and that if the owner remains silent and fails to assert his remedy until after the improvement has been made and paid for by the municipality, he cannot resist the tax assessment on-the ground of illegality of the proceedings ; and this, though it does not appear that the owner had knowledge of the illegality. Of this class are Hampson v. Mayor, 36 N. J. L. 159, and Youngster v. Mayor, 40 N. J. L. 244. Of the correctness of these and like cases, it is not necessary to say aye or nay.
There is another class of cases where parties who have been guilty of laches in asserting their remedy have been held not entitled in equity to an injunction restraining the collection of a tax, but are left to their remedy at lato. Of this class is Kelley v. Ely, 15 Ohio St. 64, and Metz v. Detroit. 18 Mich. 495, 528.
*396There is yet another class, the principle of which may well apply to cases of the sort now being considered. Principal among these are the cases of City v. Gilbert, 31 Iowa, 356; Bidwell v. Pittsburg, 85 Pa. St. 412; State ex rel. v. Mitchell, 31 Ohio. St. 281, and Tone v. Columbus, 39 Ohio St. 281. The Iowa case was where property-owners signed and presented a petition to the city council asking for improvement on certain streets. 'The council granted their prayer. It was held that such petitioners, after their request had been complied with, could not resist payment of the tax on the ground that two-thirds of the property-owners had not signed, as was required by law. The court said, “that after having thus signed and presented the petition to the city council, thereby inducing the city to enter upon the improvement requested in the petition, the defendant is «estopped from objecting that his petition was not sufficiently signed.” This case has been frequently cited as illustrating and approving the principle now under review, but not necessarily as approving the correctness of applying the principle to the particular facts of that case. And so we wish to be understood in citing it. That there may be an estoppel in such character of cases is asserted in many adjudications, but that the court was correct in applying the principle to the particular facts of that case is denied. In Matter of Sharp, 56 N. Y. 257; Tone v. Columbus, supra. The latter cases hold that the petitioners have a right to rely upon a performance of its duty by the board which required it, before basing any action on the petition, to ascertain whether a sufficient number had been signed to confer jurisdiction.
In the Pennsylvania case, supra, the property-owner signed a petition asking for a street improvement under a certain law; in pursuance of this petition the ordinance was passed, the signer was elected and acted as one of the commissioners to superintend the work, sell the city bonds, expend the proceeds on the street, and make the assessment, including his own. It was held he *397was estopped from denying the validity of the law or the mode of assessment. In the course of the opinion the cour.t said : “ The authorities acceded to the request. They altered their previous position. They assumed the* large additional indebtedness, relying upon the words and conduct of the petitioners. The latter declared that they would submit themselves to all the charges and. responsibilities imposed by that act. They wilfully caused the authorities to believe this as a matter of fact. So believing, the authorities acted upon it. They accepted the offer in the terms in which it was made. The petitioners directed the work. They received and enjoy the benefits. To now permit them to deny the truth or the efficacy of the assurance given, and continued during the progress of the work, would work a fraud on the city which cannot be sanctioned.”
In the case of State ex rel. v. Mitchell, 31 Ohio St. 592, where abutting property-owners caused a street to' be improved by initiatory steps of their own, and the bonds of the city to be negotiated to pay for the improvement, they, that is, those causing these things to be done, were held to be estopped from denying the validity of an assessment to pay such bonds, though all was done' under a law that was unconstitutional. And so it was held in Tone v. Columbus, 39 Ohio St. 281, that active participation in causing an improvement to be made will estop the party engaged therein from denying the validity of the assessment; but that to estop him from mere silence, it must be shown, among other things, that he had knowledge of the infirmity or defect in the proceedings which he is to be estopped from asserting.
If the infirmity in the case before us went to the original power of the board of aldermen to make improvements, such as that the law under which they acted was unconstitutional, as in the Ohio cases, we-might have to consider whether silence merely would work an estoppel, under the ruling in State v. Railroad, 74 Mo. 163, where nothing is said of knowledge or notice. But as the infirmity in this case arises, not from *398.a want of power,.but from the mode of exercising it, I .should hold that silence with knowledge of the work, and of the defect in the proceedings, would complete the estoppel as to the validity of those • proceedings. I .regard the foregoing cases as authority for this assertion.
But while I recognize the legal proposition that, though the contract in this case was invalid, the defend.ant may be estopped from denying its validity, I do not ■ concede that he has been shown to be in a position, or to lave done anything precluding him from attacking the legality of the proceedings. He has taken no part in •the movement whatever. He initiated no proceedings. He did not petition for the passage of the ordinance nor the improvement of the street. He took no part in ■making the contract, nor did he ask that it be changed from the terms of the ordinance. Though he knew the work was being done, he, knowing the law authorized .such improvements under certain restraints and conditions, might well have assumed or supposed those conditions had been complied with and those restraints provided. He had a right to rely upon the authorities doing their duty .under the law. Tone v. Columbus, supra.
I am, therefore, of the opinion that if it can be .shown on retrial that defendant, by himself, or in connection with others, procured the substitution of tlié contract made for the one contemplated by the ordinance, he will be estopped to deny the validity of this assessment. So he will likewise be estopped if it can be shown that, though'taking no part in the change of the contract himself, he had actual knowledge of the •change or substitution having been procured by others,’ and knowingly acquiesced in the work done thereunder. In either of these cases he has by his own act induced .and caused Anderson to.-alter his position to his prejudice, and brings himself under the correct principle of ■estoppel. It may be said that defendant will be pre.sumed to have had knowledge of the ordinance and of *399its provisions, and, therefore, when he saw the work being done, he knew that it was not in accordance with the ordinance. It is true that generally one will be presumed to know of the by-laws of a municipal corporation, but in a case of estoppel by silence, of the kind here considered, there must be actual knowledge. “There is no such thing as estoppel in pais for neglecting to speak or act when the party did not know the facts which, if known, would have made it his duty to speak or act.” Acton v. Dooley, 74 Mo. 63. “An estoppel in pais is a moral question.” Delaplaine v. Hitchcock, 6 Hill, 17. There must be in it some element of fraud. “The doctrine of estoppel in pais always presupposes error on one side and fault or fraud upon the other.” Morgan v. Railroad, 96 U. S. 716.
V. At the request of plaintiff the court gave instruction number five, set out in the statement. The effect of this instruction is, that, notwithstanding the work was not done in accordance with the terms of the ordinance, notwithstanding it was done under the contract substituted for that contemplated by the ordinance, and notwithstanding there may be no estoppel, yet plaintiff may enforce a statutory special tax lien against defendant’s property on a quantum meruit. I think this •cannot be done. A tax lien of this nature is, in all cases, to be enforced by virtue of valid proceedings authorizing the assessment; for though these proceedings in some cases may, in actual fact, be infirm, improper, and invalid, the tax is yet enforced, by estoppel, on the theory that they are sound ; that is, they are asserted to be legal upon the one side, and the other is not permitted to deny it. He is not allowed to say the truth, when by reason of his own conduct it would work a fraud upon the other party. These are not cases for quantum memit or quantum valebat. They are not cases of voluntary contract between individuals, but are statutory proceedings in inmtum where the party mhst respond, nolens volens. Plaintiff must enforce his lien •on the actual validity -of .the contract, or by estoppel, *400and in no other way. II this instruction can be allowed, a tax lien may be enforced for an improvement made in violation of the terms of the ordinance, or by one step further in direct line, without any ordinance. Of course, it is not meant to say that a contractor cannot enforce his lien unless he has precisely and minutely complied with his contract. In this, as in other cases, substantial compliance is sufficient. But here there has been no accidental, or unavoidable, or immaterial deviation from the terms of the contract. There is not an imperfect execution of the terms of the contract, but a wilful substitution of other matter. A contractor’s idea, judgment or caprice is not to say of what material a street may be improved. The law has left that to another tribunal. If that tribunal says one sort, it is not for the contractor to say another. He must endeavor to comply with his contract, and he must meet with substantial success, else he cannot enforce his lien.
VI. Other objections urged by defendant are not thought to be well founded. By the terms of section four of this ordinance, if the property-owner desired to do the work himself, he should have given written notice to the chairman of the street and alley committee of his desire to do so within ten day s after the passage of the ordinance. He was presumed to know of this ordinance (Palmyra v. Morton, 25 Mo. 593); and if he wished to avail himself of its terms, he should have done as it is therein directed. The ordinance in Leach v. Cargill, 60 Mo. 316, is unlike this. That ordinance called for affirmative action by the city engineer.
The judgment is reversed and the cause remanded.
Hall, J., concurs; Philips, P. J., having been of counsel, not sitting.