The plaintiff seeks by this suit in equity to restrain the enforcement of an alleged amendment to the zoning by-law of the town of Belmont so far as it affects certain land owned by him. The defendants answered to the merits. The case was referred to a master under the usual rule requiring him to hear the parties and their evidence, and to find and report the facts. The master has filed a comprehensive report covering the issues raised. An interlocutory decree was entered overruling the exceptions to and confirming the master’s report, from which there was no appeal. A final decree was entered granting relief. The appeal of the defendants brings the case here.
The defendants have urged that the plaintiff is not entitled to proceed in equity and that the sole and adequate remedy for his alleged wrongs was at law. That *39defence is not open at this time. Apparently it never was raised until the argument before the full court. It must be held to have been waived by answering to the merits and by going to trial before the master without objection. Bauer v. International Waste Co. 201 Mass. 197, 200, 201. Reynolds v. Grow, 265 Mass. 578, 580, 581, and cases there reviewed. Radway v. Selectmen of Dennis, 266 Mass. 329, 336. There was resort to equity without objection in Nectow v. Cambridge, 260 Mass. 441. Euclid v. Ambler Realty Co. 272 U. S. 365, 386. See, also, Hanscom v. Malden & Melrose Gas Light Co. 220 Mass. 1, 3; McArthur v. Hood Rubber Co. 221 Mass. 372, 374.
There is no report of the evidence. Therefore the findings of the master must be accepted as true unless they are inconsistent with each other, or contradictory, or plainly wrong in view of incontrovertible facts. Glover v. Waltham Laundry Co. 235 Mass. 330, 334. Prudential Trust Co. v. McCarter, 271 Mass. 132, 139.
The master has found that, prior to April 1, 1926, the defendant town had adopted a zoning by-law pursuant to authority conferred by G. L. c. 40, §§ 25-30, both inclusive, and acts in amendment thereof. Thereby the territory of the town was divided into four zones, designated as single residence districts, general residence districts, local business' districts and general business districts. No attack is made upon the validity of this zoning by-law as originally adopted. Ón or about April 1, 1926, the plaintiff bought a lot of land on Common Street in the defendant town. Prior to that purchase, he made with reference to this lot a careful examination of the zoning by-law of the town and of its accompanying map purporting to show the precise boundaries of the several districts into which the town had been zoned, and studied the situation on the ground. He conferred with local real estate brokers. There was unanimity of opinion that the lot was zoned in a local business district. The plaintiff reached that conclusion. Accordingly, he made the purchase. Apparently the exact location of *40the zoning line between a local business district and a general residence district, with respect to the land purchased by the plaintiff, was not clear beyond peradventure on superficial examination because of a possible indefiniteness in the zoning map. The master has found, after careful study of the zoning map and examination of the locality, and interpretation of the map in the light of his observations on the face of the earth, that the land of the plaintiff was included within a local business district. It is not necessary to discuss the zoning map in detail because it was applied to the locus in connection with the view by the master, whose determination in this particular must be accepted as true even though it be assumed not to rest upon oral testimony of witnesses. Commonwealth v. Dascalakis, 246 Mass. 12, 29, 30. Scrutiny of the record and of the copy of the plan does not warrant disturbance of this finding.
In September, 1926, the building inspector of the defendant town notified the plaintiff that his application for a permit to erect a block of stores on his land would be granted, but shortly afterwards he notified the plaintiff that, because of objection filed, the selectmen would give a hearing on the matter. Such hearing was held and the selectmen then made an order establishing as the boundary between the local business district and the general residence district a line whereby the land of the plaintiff would be in the general residence district and not in the local business district. This order of the selectmen could have no effect in altering the true boundary line between these two districts established by the zoning by-law as found by the master. There is nothing in the record, the zoning by-law, or the statutes, vesting jurisdiction over such a matter in the selectmen. The provisions of G. L. c. 40, § 27, as amended by St. 1925, c. 116, § 2, do not extend so far. No attempt appears to have been made to proceed under § 27A, added to G. L. c. 40 by St. 1924, c. 133.
The planning board of the defendant town was empowered by the zoning by-law, upon petition or of its *41own initiative, to hold a public hearing after specified notice “ for the consideration of amendments altering the boundaries of any district hereby established . . . and to submit to the Town for action- its recommendations in regard to the same.” Pursuant to this authority, both upon a petition and upon its own initiative, the planning board gave a hearing on changing the boundary of these zoning districts affecting land of the plaintiff. The plaintiff was heard, as were other owners of land in the vicinity, before the planning board. Such hearing and any recommendation by the planning board were voluntary and under the by-law and did not arise from deputization by a town meeting with respect to some specified subject before it for action.
The warrant for the annual meeting of the defendant town held in March, 1927, contained an article, “ To see if the Town will vote to modify the existing Zoning ByLaw as heretofore adopted by the Town by providing that the dividing line between the general residence district and the local business district ” in the neighborhood in question “ shall be the dividing line between Lots 225 and 226 as shown on plan, on file in the Town Clerk’s office, for the distance of one hundred feet easterly from Common Street, measured at right angles from said Common Street, as recommended by the report of the Planning Board on file in the Town Clerk’s office, or in any way act thereon.” The proposed dividing line described in this article and recommended by the planning board placed all the front part of the plaintiff’s land in the local business district. When this article came up for consideration at an adjournment of the annual town meeting, the plaintiff and his counsel were present. The counsel asked to be heard in behalf of the plaintiff, but permission was refused. The plaintiff himself, not being a resident of the town, because of that refusal did not ask to be heard personally. A motion to adopt the recommendation of the planning board was lost. Immediately thereafter, an owner of nearby land in the general residence district presented a motion to “modify *42the existing, zoning by-law of the Town by establishing the dividing line between the general residence district and the local business district ” by a defined line whereby the land of the plaintiff would be indubitably within the general residence district. That motion was passed by a vote of one hundred and thirty to thirty-four. The master further found that the land of the plaintiff here in issue was not suitable for purposes of residence and was plainly of the class usable for local business purposes.
The question for decision upon this branch of the case is whether the alteration of this dividing line voted by the town meeting was legally adopted and the zoning by-law thereby lawfully amended and altered. It. is provided by G. L. c. 40, § 30, as finally amended by St. 1926, c. 216, § 1, in force at the time of the events here .under review (see now St. 1929, c. 39): “ No ordinance or by-law enacted under section twenty-five shall be repealed or modified except after reasonable notice of the proposed repeal or modification and an opportunity to the objectors to be heard thereon.” This requirement must be interpreted in the light of the essential design of the zoning statute and of every by-law adopted pursuant to its terms. That design is to stabilize and to standardize the uses of real estate in specified districts for the promotion of the public health, the public safety, the public morals and, in a somewhat strict sense, the public welfare. Kane v. Board of Appeals of Medford, 273 Mass. 97, 104. The manifest aim of this section is to permit alterations in the boundaries of districts thus established only after such full notice as shall enable all interested persons to know what action is being proposed and to be afforded reasonable opportunity to present facts and arguments in protest against the contemplated changes. In towns under existing statutes and law, the only authoritative and effective way for bringing to the attention of interested persons a proposed repeal or modification in a zoning by-law is by inserting an article in the warrant for a town meeting setting forth in definite terms that which is proposed. In this connection reference may be made to *43G. L. c. 39, § 10, regulating warrants for town meetings. It there is provided that “ No action [taken at a town meeting] shall be valid unless the subject matter thereof is contained in the warrant.” The article in the warrant here in question set out with accuracy a clear and certain modification. It was the one proposed by the planning, boárd. Ample information was open to everybody in interest in advance of the town meeting as to the subject to be presented for consideration. Reasonable notice thus had been given to all entitled to it under the law. That subject was clearly before the town meeting. The vote of the town was adverse to the change proposed and set forth in the warrant. No further action, such as renewed investigation, or recommittal of the matter to the planning board or to a special committee, or other decision by the town meeting, was mooted touching that change. Thus that proposed change came to an end. Wood v. Milton, 197 Mass. 531, 533.
The motion made to substitute a modification of the dividing line between the two districts, different from that described in the article in the warrant, was not rightly before the town meeting. The single modification of the existing zoning by-law set forth in the warrant for the town meeting was the only modification of which any notice was given to the voters or to the public. By the inexorable terms of the controlling statute, said § 30 already quoted, so far as here material, there can be no modification of a zoning by-law “ except after reasonable notice of the proposed . . . modification.” The implication of the context of these words is that, since modification can be made only by the town at a town meeting, the requisite" notice must be given in the warrant for that meeting. The concluding words of the article in the warrant for the town meeting at which the vote here in question was passed, namely, “or in any way act thereon,” do not justify the vote actually taken as to a modification of the dividing line. Those concluding words cannot enlarge or affect in any way the mandate of the statute to the effect that no zoning by*44law can be “ modified except after reasonable notice of the proposed . . . modification.”
It is a settled principle that warrants for town meetings are to be liberally interpreted ánd are not to be construed with great strictness. . It is sufficient if intelligible notice of the subject tó be considered is given. Substantial certainty as to the nature of the business to be acted upon is all that is required. Grover v. Pembroke, 11 Allen, 88. Coffin v. Lawrence, 143 Mass. 110, 112. Commonwealth v. Wentworth, 145 Mass. 50, 52. That principle is not applicable to the case at bar. It cannot validate a vote changing the dividing line between two districts established by a zoning by-law of which no notice was given in the warrant for the town meeting. So to hold would be contrary to the clear requirement of the governing statute. That statute demands an exact statement of a defined proposed modification of a zoning by-law. Its provisions are not satisfied by a general and unspecified reference to a possible modification not set forth in unmistakable terms, either in the words of the warrant for the town meeting or by reference to easily available reports, plans or documents. The concluding words of the article in the warrant, “ or in any way act thereon,” in substance frequently occur in articles for town meetings touching matters generally cognizable by towns. In the article in question their only force and effect relate to the single specified modification recommended by the report of the planning board on file with the town clerk. That modification may be dealt with by the town meeting u jn any rational way by vote. But some other modification cannot be adopted instead of that one.
The facts already narrated show that the plaintiff was accorded no opportunity to be heard upon the change in the dividing line voted by the voters at the town meeting.
It follows that there has been no modification of the dividing line between the general residence district and the local business district as established by the zoning by-law in its. original form. That line, still subsists.
*45Stipulation was filed with the master during the hearings reciting application by the plaintiff for a building permit to erect stores on his lot, the decision of the building commissioner to issue such permit, the decision by the selectmen on objection that no such permit be issued, and the determination by the selectmen in the form of an order that, so far as they had authority, the dividing line between business and residence districts so far as concerned the locus was in such place that the plaintiff’s lot was in a residence district, the bringing of a petition for certiorari by another landowner, similarly affected as was the plaintiff by such determination, to quash the order of the selectmen and the dismissal of that petition after hearing, the bringing of a like petition for certiorari by the plaintiff, and after the dismissal of the other petition the entry of judgment by agreement of parties that the petition of the plaintiff be dismissed. In these circumstances the petition for certiorari by the plaintiff constitutes no bar to the maintenance of the present proceeding. The cause of action is different. The issues are quite different. The doctrine of res judicata is not applicable. Newburyport Institution for Savings v. Puffer, 201 Mass. 41, 49. Shapiro v. Park Trust Co. 253 Mass. 383. Capaccio v. Merrill, 222 Mass. 308. Farnum v. Brady, 269 Mass. 53. Guild v. Cohen, 269 Mass. 241. Wight v. Wight, 272 Mass. 154, and cases cited.
References are made in the brief filed in behalf of the defendants to other matters not set out in the master’s report and outside the present record. No consideration can be given them. Of course, the proceeding by the other landowner in certiorari had no effect on the rights of the plaintiff. Old Dominion Copper Mining & Smelting Co. v. Bigelow, 203 Mass. 159, 206, 207.
Several criticisms of the details of the decree are made by the defendants. The first paragraph, in that it declares the vote of the town attempting to modify the dividing line established by the zoning by-law illegal and void, is broader than the allegations of the bill and for *46that reason alone may be amended to indicate that this declaration of nullity extends only to land of the plaintiff.
The zoning by-law had no effect upon established and existing building restrictions. Riverbank Improvement Co. v. Chadwick, 228 Mass. 242. Vorenberg v. Bunnell, 257 Mass. 399, 408. The subject of building restrictions outside the zoning by-law is not involved in the case at bar and has not been tried. No reference need be made to it in the decree.
The master’s report affords no basis for a determination that a part of the plaintiff’s lot is within the general residence district. The finding of the master on unreported evidence is in effect that it is all within the local business district.
There is no legal objection to the mandatory provisions of paragraph 4 of the final decree directing the building inspector to issue a permit to the plaintiff to erect stores upon his lot after finding that his plans therefor are in conformity to the by-laws of the town. The effect of this paragraph is to compel the building inspector to perform the duties resting on him by law when relieved of the impediments assumed to have existed from the matters here determined to be no obstacle in his way. Goldstein v. Conner, 212 Mass. 57. Kilgour v. Gratto, 224 Mass. 78. Police Commissioner of Boston v. Boston, 239 Mass. 401.
Every question argued by the defendants has been considered. No further discussion is required. It becomes unnecessary to refer to other grounds for relief urged in behalf of the plaintiff. The final decree may be modified by adding at the end of its first paragraph the words, “ so far as concerns land of the plaintiff,” and as thus modified is affirmed with costs.
Ordered accordingly.