Opinion by

The proposition that the ordinance of April 1, 1880 was repealed by the paving ordinance of October 5,1892, cannot be sustained. They are in pari materia and are to be construed together. ' The later ordinance created the condition to which the earlier general ordinance became applicable. Thus viewed there is no conflict between them. Applying the well settled principles governing the construction of statutes and ordinances which are in pari materia the paving ordinance is to be construed as if it contained an express provision that the owners of property abutting on the improvement and paying assessments thereon should be entitled to an annual abatement of city taxes on said property of five per centum of the cost of the pavement per lineal foot for the term of ten years. This provision was fairly, within the authority conferred by the local Act of May 9,1871, P. L. 630, and is not in conflict with any provision, that has been called to our attention, of the act of 1874 or 1889, regulating the making of such improvements in cities of the third class. Pursuing the same line of thought the learned judge below says: “ The city proceeded, under the authority of the *140petition, to pass an ordinance for paving the street, and the existing ordinance, applicable to all such cases, must be read into this special provision for the particular case. So read, the enactment substantially is that the pavement shall be paid for in the first instance by the owners of lots, and that the owners shall receive back again 50 per centum of the amount so paid, by way of annual abatement of taxes. This amounts to a promise on the part of the city, for which the defendant has given a sufficient consideration, by signing the petition and by paying his assessment of the costs of the improvement.” But it is argued that the act of 1871 was abrogated by the provisions of sections one and two of article nine of the constitution. It is undoubtedly true that it confers powers which could not be exercised, to the fullest extent, by councils, without coming in conflict with the constitutional provisions with reference to uniformity of taxation and exemption from taxation, and to that extent it was modified, and its operative force is restrained, by the latter; but it does not necessarily follow that it was wholly repealed so as to prevent the exercise of powers conferred by it not inconsistent with the provisions of the fundamental law. The question then arises, — whether an act authorizing a city, having power to pave streets at the expense of the city or of the abutting property owners or partly at the expense of the city and partly at the expense of the abutters, to allow the latter an abatement of their general city taxes on the same property, equivalent to a portion of the assessment for the improvements, — is in cokflict with the constitutional provisions under consideration. We are justified in saying that this is the main question in the case, for it is very clear that the city of Erie had this power, unless it was taken away by the constitution. We are of opinion that such a law neither offends against the constitutional provision requiring uniformity of taxation nor against that forbidding the enactment of laws exempting property from taxation. When in the exercise of the discretion of the municipal authorities a local improvement has been determined upon and it has also been determined that it would be just to make the city and the abutters bear the expense proportionately, every dollar which one of the latter pays in the first instance beyond his due proportion is in relief of the city and goes to the benefit of other taxpayers. A law *141which in its practical operation permits him to apply this overpayment in discharge of the general taxes against the same property manifestly tends to produce uniformity and equality of taxation rather than the contrarjr. For the same reason it is not an act exempting property from taxation. It simply provides a mode for equalizing the burdens of taxation, and making each citizen bear his due proportion.

The remaining question is as to the effect of the repealing ordinance of September 16, 1895, upon the rights of persons who paid the paving assessments against their properties. The authorized body of a municipal corporation, acting within the scope of its powers, may bind it by an ordinance, which, in favor of private persons interested therein, may, if so intended, operate as a contract: 1 Dill. on Mun. Corp., ¶¶ 450, 474, citing W. F. Savings Soc. v. Phila., 31 Pa. 175; Same v. Same, 31 Pa. 185. A repeal of a valid ordinance of this nature, and thus intended to operate as a contract, cannot operate retrospectively to impair private rights vested under it. Ibid., ¶¶ 314, 450. As the learned judge below well says : “ A municipality although vested with legislative powers, is competent to contract, and amenable to judicial coercion, and it cannot legislate away its agreements.” It is to be observed that the paving ordinance was passed pursuant to a petition of the abutting property owners. This petition enabled the city councils to pass-the ordinance by a vote of a majority of all the members elected, whereas, without petition, a two thirds vote of all the members would have been necessary. Presumably the property owners had in view the ordinance of 1880, and were influenced by it in petitioning for or refraining from opposing the paving ordinance. It was in the nature of an inducement held out to them by the city, — a proposition which was accepted. Furthermore (and this is a consideration which applies to the case of all the abutters, whether petitioners or not), it was just as much a part of the plan or scheme under which the pavement was ordained and laid as if the councils had declared in so many words that one half the cost of the pavement should ultimately be borne by the city. Is it too much to say that the city assumed an obligation which it could not repudiate by a subsequent repeal of the ordinance? We think not. The *142question as to the power of a municipality to “ contract away thé taxing power delegated to it is not fairly raised in this case. If, as is conceded by the appellant’s counsel, the city had authority to lay the pavement partly at the expense of the city and partly at the expense of the abutters, and, if we are correct in holding that the paving ordinance and the ordinance of 1880 taken together are to be construed as an exercise of that power in a lawful although perhaps roundabout mode, it would seem to follow as a self-evident proposition that the abutter who performed all that the ordinance required of him acquired a vested right to have the city bear the portion of the burden imposed upon it, which right could not be impaired by a subsequent repeal of that portion of the ordinance. The purpose and ultimate effect of the ordinance is not to exempt or partially relieve his property from taxation, but to reimburse him out of the taxes levied upon his property to the extent that he has contributed in the first instance to pay the city’s share of the cost of the improvement. The city had the power, if the conditions warranted it, to lay the pavement wholly at the expense of the abutters. It also had the power — and we must presume that this was a proper occasion for its exercise — to apportion the cost between the city and the abutters. This was a matter resting in the discretion of the councils ordaining the improvement, and the mode of exercising it was wholly in the city’s favor, since thereby the payment of its share of the expense was distributed over a period of years. But having exercised its discretion, the pavement having been laid and the assessment having been paid, its power was exhausted; it could not afterwards shift its share of the burden upon the shoulders of the abutters. We concur with the learned judge below in holding that the repealing ordinance is valid, but it cannot affect the vested rights of abutting property owners under the original ordinance.

Something Avas said upon the argument as to the creation of a municipal indebtedness beyond the two per cent limit, but we cannot find that any question of that nature is raised in the case stated. Nor is it alleged that the allowance of the abatement will diminish the annual revenues from ordinary taxation to a point where it will be impossible for the city to provide *143for its necessary current expenditures. So far as appears, there is nothing to prevent the city from discharging the obligation it assumed in the defendant’s favor according to its spirit and intent.

Judgment affirmed.