Evans, J.
(After stating the facts.) 1. In Barber v. Alexander, 120 Ga. 30, and in Neal v. McWhorter, 122 Ga. 431, this court held that the school law contained in the Political Code, §§ 1338-1408, was a general law, by which it was declared that each county shall comprise one school district, and that a special law creating a district within a district destroys territorial uniformity and sets apart one locality in the State in which an existing general law is not longer to be of force. The special act describing a circumscribed area of a county as a school district and providing for the establishment and operation of schools within the defined area was adjudged to be null and void, because it opposed the constitutional inhibition that “no special law shall be enacted in any case for which provision has been made by an existing general law.” The local acts involved in those decisions were enacted before the ratification by *251the people of the amendment to art. 8, sec. 4, par. 1, of the constitution. The attack on the constitutionality of the local act incorporating the Hopeful school district is the same as was made on the special laws in those cases; and unless the former act is saved by the amendment, under the authority of the cited cases it will have to be pronounced unconstitutional.
Art. 8, see. 4, par. 1, of the constitution originally was as follows: “Authority may be granted to counties, upon the recommendation of two grand juries, and to municipal corporations upon the recommendation of the corporate authority, to establish and maintain public schools in their respective limits, by local taxation; but no such local laws shall take effect until the same shall have been submitted to a vote of the qualified voters in each county or municipal corporation, and approved by a two-thirds vote of persons qualified to vote at such election; and the General Assembly may prescribe who shall vote on such questions.” Civil Code, § 5909. It was amended so as to read: “Authority may be granted to counties, militia districts, school districts, and to municipal corporations, upon the recommendation of the corporate authority, to establish and maintain public schools in their respective limits by local taxation; but no such laws shall take effect until the same shall have been submitted to a vote of the qualified voters in each, county, militia district, school district, or municipal corporation and approved by two-thirds majority of persons voting at such election, and the'General Assembly may prescribe who shall vote on such questions.” Acts of 1903, p. 23. The subject-matter of this article of the constitution is “Education.” The first section declares that “there shall be a’ thorough system of common schools for the education of children in the elementary branches of an English education only, as nearly uniform as practicable, the expenses of which shall be provided for by taxation or otherwise.” The next section creates the office of State school commissioner; the third section sets apart certain funds and incomes for the support of the common schools. • Then follows the fourth section, above set out, which empowers the legislature to confer authority on the taxing districts therein named to establish and maintain public schools in their respective limits by local taxation. This section does not attempt to locate any school district, but constitutes each school district, when located and established, as a taxing district. The effect of the amendment *252to section 4 is to enlarge the number of taxing districts, and not to provide for the manner of their creation. The legislature may ■establish and define the location of school districts by a general law, or, in the absence of any general law, it may by special act incorporate a designated area into a school district. But the legislature can not by a special act create a school district so long as there is of force a general law whereby school districts are defined and established. It is restrained from so doing by the constitution, and the amendment to section 4 of article 8 does not authorize ■ the General Assembly by special act to create a school district so long .as there is of force an existing general law by which school districts ■ are created, which embrace an entire county, and no ¡orovision is therein made for segregating a portion of the territory of the county into a local school district which shall be governed by other regulations than those named in the general act.
2. It is urged that the parties complaining of the unconstitutionality of the law are estopped from denying that the law -is ■ constitutional, for the reason that they were active in having it put into operation. In cases where a public improvement is made, or ■ a tax is laid, upon the petition of the owners of adjacent property, •or other persons interested, and pursuant in form to and in compli.ance with the statutes of the State, or where the property owners in some way actively encourage the assessment, a kind of estoppel ■arises against the persons who made the petition or gave the encouragement. Gray, Lim. Tax. Power, § 1999a. A defense of this nature rests less on the principle of estoppel than it does on the liability of implied contract that an abutting landowner, having received the benefit of the improvement made, because of his active participation in procuring’ the improvement under an invalid law, will be required to pay for it according to the terms of such law. But whether we denominate a defense of this kind as an estoppel ■or an implied assumpsit, such defense does not go to the validity of the law, but is upheld because it would be inequitable to restrain the collection of a fax to pay for an improvement which the complaining party procured to be made: “Courts can not, by the execution of an unconstitutional law as law, supply the want of power in the legislative department.” O’Brien v. Wheelock, 184 U. S. 489. Nor will this doctrine of estoppel be applied to a taxpayer ■who has done nothing to encourage the legislation or the incurrence *253of expense on the faith of the invalid or unconstitutional law; as to-him, the unconstitutional law is no law, and if he has not estopped, himself, he may resist the collection of the tax levied under such invalid law. This doctrine of estoppel by conduct is subject to a still further limitation: the person said to be estopped will not be' concluded as to acts not done strictly within the purview and by authority of the invalid act. If the officials charged with the enforcement of a statute which subsequently turns out to be unconstitutional incur any expense unauthorized by the law, they can not by the levy of a tax compel a taxpayer to defray such illegal expense. And it is further to be observed that parties are not es-topped from questioning the constitutionality of an act in the supposed validity of which they have acquiesced, as to such matters as yet remain to be done in the future under the act and as to expenses not yet incurred. Mott v. Hubbard (Ohio), 53 N. E. 47. In the present cáse, the plaintiffs do not seek to escape payment-for the benefits of the local school system which they and their neighbors have derived in the past. On the contrary, the plaintiffs simply ask that a halt be called in the illegal enforcement of the local school law, that the school affairs of the locality in which they live shall again assume a legal aspect, and that no expense, to' be met by local taxation, be -incurred by the trustees for the future operation of the schools. The reply of the trustees is that they have already gone so far in making arrangements to operate the schools for another year, and have incurred such an indebtedness, on the faith of the plaintiffs’ apparent acquiescence in the project, it would be inequitable for the courts at this time to interfere therewith, notwithstanding there is no authority of law for carrying it. 'into effect.
The defendants disclose by their answer, (1) that in financing their illegal school project they have, without any authority under' the act of 1905, borrowed two inconsiderable sums of rponey from private parties, with the understanding that repayment should be made out of the local school tax fund which they expected to collect in the fall of the year. Granting that these private individuals may have been misled into parting with their money by the-belief that the plaintiffs recognized the school act as valid, yet the former were bound to know that the trustees, under that act, were-without authority to anticipate the realization of funds for school *254purposes'-under the taz levy therein provided for; and certainly the plaintiffs are not to be held accountable for an existing state of facts brought about by the illegal conduct of the trustees in- overstepping their supposed authority, for the plaintiffs were not bound to anticipate that the trustees would violate the statute which gave them being. The defendants show (2) that the trustees have entered into contracts with teachers, in no part as yet performed, for the scholastic term which was to have begun on the first Monday in September, 1906. The plaintiffs have never received any benefit under these executory contracts for which in equity they are bound to account; the contracts themselves are not legally enforceable, since they depend for their vitality on an unconstitutional act; and, so long as they remain executory, the courts can not, under the doctrine of estoppel or otherwise, indirectly give full effect to that act by treating these contracts as valid and subsisting obligations upon the taxpayer.
And lastly, the plaintiffs are said to be estopped, because the trustees, in the month of January preceding the filing of the petition, had bought on credit a mule, as well as feed for the same, and this indebtedness was incurred on the faith of the plaintiff’s acquiescence in the validity of the local act. It is not necessary to question the propriety or legality of the purpose of the board of school trustees to furnish transportation to pupils residing at a distance from the schoolhouse -established by them, the expense to be paid out of the fund realized from a tax levied for the maintenance of the school. For the purposes of this case, we may concede that the purchase of a mule and provender came within the purview of the act, and was proper in order that some of the pupils might be transported to the school. As we have pointed out, the plaintiffs are not estopped by the executory contracts with the teachers, nor by the unauthorized loans; and as the act is unconstitutional, the trustees can not further legally maintain the school. It would therefore seem absurd to hold that .the plaintiffs are es-topped to question the legality of the tax, because of the alleged necessity of raising funds to pay- for a mule which can not be longer used in connection with the school. Eather would it be more equitable to say that the trustees should return the mule and the unused-provender, if any, to the seller, who at the time he sold the same was legally chargeable with knowledge, not only *255of the unconstitutionality of the local school act, but. that the trustees had no authority thereunder to make purchases on credit and pledge-as security for payment therefor the fund which they expected to realize from the imposition of an illegal tax. The buying of the mule and provender on credit stands upon the same footing as the unauthorized borrowing of money to be used for school purposes.
In reaching the conclusion, as we do, that there was no merit in the defense of estoppel interposed by the defendants, we have not overlooked the case of Irvin v. Gregory, 86 Ga. 605, wherein it appeared that a majority of the complainants had voted in favor of the approval of a local school law and all of them had acquiesced in the result of the election until after a school was established and put into operation. The school law was, as the court ruled, a constitutional and valid law, save as to a minor detail which did not affect its validity as a whole. It provided that it should not go into effect until ratified by a two-thirds vote of the qualified voters of a town, and that notice of the election should be published once a week for four weeks. The publication was begun in time, but the notice was inadvertently omitted from the fourth issue of the newspaper, so that the notice appeared only three times. In dealing with this branch of the case, Chief Justice Bleckley recognized that this omission would have been fatal to the validity of the election, if prompt action had been taken by the plaintiffs to prevent the local act from being carried into operation; but he stated that the conclusion of the court was that the failure to publish the notice in strict conformity with the terms of the act was a mere irregularity and could not be taken advantage of by the complainants, when more than two-thirds of the qualified voters responded to the notice given and actually voted for ratification of the act, and the complainants and all others concerned acquiesced in the result of the election and waited till the school was established and put into operation before attempting to restrain the collection of the local, tax authorized to be levied by the act. The difference between that case and the one now in hand is apparent; the ruling in the former was analogized to decisions laying down the principle that irregularities in the holding of an election will not necessarily invalidate it, and may be waived by failure to contest-the election; in the present case, the plaintiffs do not undertake to set aside the elec*256tion adopting the local act of 1905, but to assert that the General Assembly was without authority to pass that act, and nothing done at the election or afterwards could operate to render it a constitutional law. The position of the plaintiffs is unanswerable; and as-there now appears to be no reason why the .further enforcement of this invalid statute should not be restrained, we hold that the-injunction prayed for should have been granted.
What is said above disposes of the controlling questions pre-' sented by the bill of exceptions, and it is unnecessary to deal specifically with each of the assignments of error made, since the-only matter now for decision is whether or not the plaintiffs were-entitled to an interlocutory injunction. Foster v. Case, 126 Ga.. 714. Judgment reversed.
All the Justices concur.