HARRIS, J.
Tbe plaintiffs contend: (1) That tbe pavement was not laid in accordance with tbe terms of tbe contract; (2) that because of its form, tbe amendment adopted by tbe legal voters of Silverton in 1917 displaced and supplanted tbe original charter, with tbe result that the amendment alone constitutes tbe whole charter; and (3) that tbe reassessment proceedings are unconstitutional and void for tbe reason that they amount to a taking of property without due process of law.
Tbe complaint alleges that the contractor failed to comply with bis contract by failing to roll tbe sub-grade with a 10-ton roller “until same made no impression thereon”; by estimating the component parts of tbe pavement instead of measuring them; by using cement without submitting samples to tbe city; by neglecting to tamp tbe mixture placed in position on tbe street with iron-shod rammers; and by permitting heavy loads to be hauled over the pavement before it hardened. Tbe same contention, based upon the same grounds of alleged failure of performance, was urged in McClaine v. Silverton, 83 Or. 26 (162 Pac. 496), where, when speaking of the same contract and the same improvement as are involved here, it was said that the evidence submitted there did not justify this court in reviewing the conclusion of the municipal authorities that there was a substantial compliance with the contract. A transcript of the evidence submitted in McClaine v. Silverton was by a stipulation of the parties here received as evidence in the present case. In addition *450to the transcript referred to, the trial court heard the testimony of eight witnesses, of whom three were called by the plaintiffs and five by the defendants. The trial court in the instant case found from the evidence that “said improvement was completed substantially as agreed upon.” Here, as in McClaine v. Silverton, the evidence is conflicting, and after a careful examination of the whole record, we do not feel justified in disturbing the findings of the trial judge.
1. The contention that the amendment constitutes the whole charter is without merit. In 1891 the legislature enacted a charter consisting of 130 sections: Laws 1891, p. 530. In 1911, the legal voters exercised the power of the initiative, and added sections 131, 132, 133 and 134 to the charter. The amendment of 1917 merely enlarges tha then existing charter by adding four sections, and by numbering them consecutively with reference to the 134 sections of the then existing charter. The amendment of 1917 conferred the power of reassessment where that power did not previously exist. The amendment of 1917 was not enacted as a revision of the original charter, nor as a substitute for all that had been done before; but it was. passed as a supplement to the then existing charter. The amendment did not change or modify a single word in any of the 134 preceding sections. Sheridan v. Salem, 14 Or. 328 (12 Pac. 925), is a precedent squarely in. point, for there the facts were like those presented here, and it was there ruled that the amendment was not controlled by Article IV, Section 22, of the state Constitution, which commands that “no act shall be revised or amended by mere reference to its title, but *451the act revised or sections amended shall be set forth and published at length.”
2. Even though we assume, without deciding, that Article IV, Section 22, of the state Constitution, governs not only the legislative assembly when adopting an act, but also controls the legal voters of cities and towns when exercising the power of the initiative, nevertheless this section of the Constitution does not apply to the amendment of 1917, for the reason that legislation which does no more than to add new sections to an existing act, without modifying or altering the original act, does not come within the embrace of constitutional provisions like Article IV, Section 22, of our Constitution: 25 R. C. L. 875.
The principle announced and applied in Nottage v. Portland, 35 Or. 539 (58 Pac. 883, 76 Am. St. Rep. 513); Phipps v. Medford, 81 Or. 119 (156 Pac. 787, 158 Pac. 666); Wagoner v. La Grande, 89 Or. 192 (173 Pac. 305), supports the conclusion that the reassessment proceedings are constitutional and valid: See, also, Wilson v. Portland, 87 Or. 507, 514 (169 Pac. 90, 171 Pac. 201); Ukase Investment Co. v. Portland, 95 Or. 176 (186 Pac. 558); Gardner v. Portland, 95 Or. 378 (187 Pac. 306). Although our conclusions could be securely rested upon the precedents already mentioned, yet, because of the earnest and learned arguments made by counsel for the plaintiffs in their written brief and at the hearing, we have examined the subject anew.
Jurisdictional requirements concerning street improvements and special assessments may, for the purposes of this discussion, be divided into two classes: (1) Those which arise out of and are compelled by organic law; and (2) those which arise out of and are compelled only by statutory law: Gray *452on' Limitations of Taxing Power, 616. The first class finds its source in written constitutions; the other in legislative assemblies.
3. When any given power is, by a statute enacted by a legislative assembly, conferred upon cities and towns, that statute must, in order to make such power available, provide for all jurisdictional requirements compelled by the Constitution; but the legislature need not, although it may if it chooses, add to such jurisdictional requirements as are compelled by the Constitution. Jurisdictional acts made necessary by the organic law may for present purposes be termed indispensable, for the reason that any attempt by legislation to confer a power is ineffective unless provision is made for such jurisdictional acts; while those made necessary by statute only, and not required by the Constitution, may be called dispensable, for the reason that the legislature is not obliged to provide for them, although it may do so if it wishes. If the legislature does prescribe jurisdictional acts in addition to those required by the Constitution, then the sum of these jurisdictional requirements, organic and indispensable as well as statutory and dispensable, constitutes the mode, and therefore the measure of the power exercisable by the municipality.
4, 5. So far as the city or town is concerned, it is obliged to heed every jurisdictional requirement, regardless of whether such requirement is purely statutory or essentially organic in its nature, for both the Constitution, and’ ordinarily the legislature, are of superior authority; and, therefore, failure to observe a jurisdictional requirement, whether organic or statutory, will usually defeat an ordinance order*453ing an improvement, and invalidate an ordinance for an assessment.
6. The right to be heard at some stage of the proceedings arises ont of the Constitution. The legislature, when enacting the charter of 1891, complied with the Constitution, and made provision for notice and an opportunity to be heard. These were indispensable and jurisdictional requirements.
7. The charter of 1891 also provided that a remonstrance, when signed by the owners of two thirds of the property adjacent to the proposed improvement, should operate as a bar to further proceedings and prevent the improvement. While, strictly speaking, a sufficient remonstrance ousts jurisdiction, we may, for convenience, speak of the filing of such a remonstrance as a jurisdictional act. The effect of a remonstrance is dependent wholly upon the statute. A remonstrance may of itself evidence the disapproval of its signers, and show that they do not acquiesce in a proposed improvement; but it has no legal effect except as provided by statute. The right to file an operative and self-executing remonstrance exists only where the statute creates the right; and, therefore, we may speak of the remonstrance filed by the plaintiffs, and others in 1914, as a dispensable jurisdictional act: Page & Jones on Taxation by Assessment, § 803; City Street Improvement Co. v. Laird, 138 Cal. 27 (70 Pac. 916); City of Atchison v. Price, 45 Kan. 296 (25 Pac. 605).
8. The council, it is true, when passing upon the remonstrance, decided that the sufficiency of the remonstrance should, under the terms of the charter, be measured by the number of front feet abutting upon the proposed improvement, and not by the superficial area of the adjacent property. The cir*454cumstance that the council was mistaken in its construction of the charter cannot affect the question, for the fact remains that the remonstrance was sufficient to oust the council’s jurisdiction to make the improvement.
9, 10. The power to tax is an attribute of sovereignty, and the power to levy a special assessment, although it is to be differentiated from a pure tax, is a branch of the power of taxation, and when exercised is a manifestation of sovereignty.
11. The fundamental doctrine of special assessments is not based upon the principles of contract; and, therefore, the charter, conferring the right to file an operative and self-executing remonstrance, plus the filing of such remonstrance, did not result in a contract with attending contractual rights and obligations: French v. Barber Asphalt Paving Co., 181 U. S. 324 (45 L. Ed. 879, 21 Sup. Ct. Rep. 625); Seattle v. Kelleher, 195 U. S. 351 (49 L. Ed. 232, 25 Sup. Ct. Rep. 44, see, also, Rose’s U. S. Notes); Colby v. Medford, 85 Or. 485, 525 (167 Pac. 487); Howell v. Buffalo, 37 N. Y. 267.
As said in Nottage v. Portland, 35 Or. 539, 548 (58 Pac. 883, 76 Am. St. Rep. 513):
“It may be regarded as settled-that the legislature may, unless restricted by the state Constitution, legalize or validate retrospectively a proceeding for the improvement of a street which it might have authorized in advance, and it may also cure defects in or make immaterial statutory requirements which it could have dispensed with in the first instance.”
The doctrine, as expressed in Frederick v. Seattle, 13 Wash. 428, 432 (43 Pac. 364, 365), is as follows:
“The rule deduced from all the authorities seems to be, in substance, that if the legislature had the power in the first instance to make valid the assess*455ment without the requirement which was disregarded by the authorities, it can by legislative enactment dispense with that requirement in providing for a new assessment.”
12. In brief, the legislature may ratify and cure through reassessment that which it might have constitutionally and lawfully authorized in the first instance. The power to validate a tax or assessment rendered invalid by errors or omissions is an essential attribute of the power vested in the legislature in its control over the sovereign power of taxation, and is necessarily without limit except as restricted or limited by the Constitution, in cases where the legislature could originally authorize the tax or assessment, although it cannot validate retrospectively what it could not originally have authorized. If a jurisdictional act is a “dispensable act” within the meaning of those words as here used, the rule, subject to certain possible exceptions, is that the legislature can cure a defect, which has resulted from failure to do a dispensable jurisdictional act, by providing for a reassessment: Spencer v. Merchant, 125 U. S. 345 (31 L. Ed. 763, 8 Sup. Ct. Rep. 921); Seattle v. Kelleher, 195 U. S. 351 (49 L. Ed. 232, 25 Sup. Ct. Rep. 44, see, also, Rose’s U. S. Notes); People v. Supervisors, 26 Mich. 22; In re Commissioners of Elizabeth, 49 N. J. Law, 488 (10 Atl. 363); Mills v. Charleston, 29 Wis. 400 (9 Am. Rep. 578); Sanderson v. Herman, 108 Wis. 662 (84 N. W. 890, 85 N. W. 141); Mayor v. Ulman, 79 Md. 469 (30 Atl. 43); City of Chester v. Black, 132 Pa. 568 (19 Atl. 276, 6 L. R. A. 802); Cray on Limitations of Taxing Power, § 1282 et seq.; 25 R. C. L. 111, 171; Hamilton on Special Assessments, § 823; Reiff v. Portland, 71 Or. *456421, 427 (141 Pac. 167, 142 Pac. 827, L. R. A. 1915D, 772).
Reassessment proceedings have been sustained: Where the reassessment was levied to pay for-an improvement for which, when the improvement was made, there was no statutory authority to levy an assessment as to a part of the improvement, and for which part the municipality had determined to pay by general taxation (Seattle v. Kelleher, 195 U. S. 351 [49 L. Ed. 232, 25 Sup. Ct. Rep. 44]); where the petition for the improvement did not contain the names of owners of one half of the property fronting on the proposed improvement (Nottage v. Portland, 35 Or. 539 [58 Pac. 883, 76 Am. St. Rep. 513]); where the work was done under a void contract (Wagoner v. La Grande, 89 Or. 192 [173 Pac. 305]); where there was a failure to observe a provision of the charter requiring the giving of notice before commencing the construction of the improvement (Phipps v. Medford, 81 Or. 119 [156 Pac. 787, 188 Pac. 666]); where the original assessment was void because of the failure to procure the consent of the necessary number of property owners (In re Antwerp, 56 N. Y. 261); where the original assessment was void because the contract for the improvement was illegally let (St. Paul v. Mullen, 27 Minn. 78 [6 N. W. 424]); where the order directing the improvement was void because of jurisdictional defects (State v. District Court, 95 Minn. 183 [103 N. W. 881]); where the order for the improvement was void because made without a certificate of the city assessor (Howell v. Buffalo, 37 N. Y. 267); where the assessment was void because there was no petition signed by the owners of more than three fifths of the front feet abutting upon the improve*457ment (Frederick v. Seattle, 13 Wash. 428 [43 Pac. 364]); where there was no estimate of the cost submitted by the engineer of the council before making the contract (Emporia v. Norton, 13 Kan. 569, 588); where the paving was done under authority of an act subsequently declared unconstitutional (Chester City v. Black, 132 Pa. 568 [19 Atl. 276, 6 L. R. A. 802]); where the order directing the improvement is by charter declared to be of no effect until the consent in writing of the owners of one half of the front footage is obtained (Jones v. Town of Tanawanda, 158 N. Y. 438 [53 N. E. 281]); and where the petition for the improvement lacks the required number of signatures (Kansas City v. Silver, 74 Kan. 851 [85 Pac. 805]).
13. The legislature was not obliged, when it enacted the charter of 1891, to include a provision making a remonstrance signed by any given number of owners operative and self-executing. The provision making a remonstrance a bar to further proceedings could have been omitted, for it was a “dispensable” jurisdictional act; and, therefore, under the rules so well established by the authorities, the legislature could, prior to the adoption of the home-rule amendments to the Constitution, have passed a special act providing for a reassessment and applying to Silverton alone: See Page & Jones on Taxation by Assessment, 1624; Manley v. Emlen, 46 Kan. 655 (27 Pac. 844). In other words, the legislature, in the exercise of its power to amend a municipal charter by a special law, could, prior to 1906, have adopted the very amendment which the legal voters of Silverton themselves adopted, and such special law would have been constitutional. The amendment *458involved was concerning an intramural power, and was within the scope of the legislative authority of the legal voters of Silverton; and it is therefore valid to the same extent as though it had been passed as a special. law by the legislature prion to 1906: State ex rel. v. Port of Astoria, 79 Or. 1, 17 (154 Pac. 399). However, nothing said here is to be construed as a judicial affirmation of the validity of Section 138 of the amendment, for the question of the validity of that section is not involved in the instant case.
14. The plaintiffs , argue that the amendment' should not be construed so as to operate retrospectively. It is true, as contended by the plaintiffs, that the settled rule of construction is that laws will not be interpreted to be retrospective unless by their terms they are clearly intended to be so: Wist v. Grand Lodge A. O. U. W., 22 Or. 271, 282 (29 Pac. 6.10, 29 Am. St. Rep. 603); Catterlin v. Bush, 39 Or. 496 (59 Pac. 706, 65 Pac. 1064).
15. As we read the amendment it clearly and plainly operates, and was intended to operate, retrospectively: See Kadderly v. Portland, 44 Or. 118, 159 (74 Pac. 710, 75 Pac. 222).
It is also contended, under the amendment “in question in the case at bar, that the right of the property owner is in effect limited to a hearing upon the amount of his assessment.” In our view of the amendment, it furnishes to the land owners “an opportunity to raise all pertinent and available questions, and dispute their liability, or its amount and extent”: Spencer v. Merchant, 125 U. S. 345 (31 L. Ed. 763, 767, 8 Sup. Ct. Rep. 921, 926, see, also, Rose’s U. S. Notes).
*459Our views of the questions presented on this appeal result in the conclusion that the decree must be affirmed without costs in either court.
Affirmed. Rehearing Denied.
McBride, C. J., and Benson and Johns, JJ., concur.