The Machinery Act, G.S. 105-271, et seg., prescribes the time and manner for listing and valuing property for ad valorem tax purposes. It also fixes the time for payment. The portions of the act pertinent to a decision of this case provide:
Property must be listed annually, G.S. 105-280. Personal property is valued annually, G.S. 105-280; real property is valued octennially, G.S. 105-278. The values are as of January 1 of the year in which the valuation is fixed. The Board of County Commissioners is required to appoint a tax supervisor, G.S. 105-283; he is responsible for the proper listing and appraising of property, G.S. 105-286. The supervisor appoints list takers, 105-287, who in the first instance determine values. But the tax supervisor has the power, at any time prior to the meeting of the Board of Equalization and Review, “to change the valuation placed on any property by the list taker.” G.S. 105-286 (g). After the property has been listed and valued, the county commissioners sit as “a county board of equalization and review.” G.S. 105-327 (a). The tax supervisor acts as clerk to the Board of Equalization and Review, G.S. 105-327 (d). The time fixed for the first meeting of the Board is “the eleventh Monday following the day on which tax listing began.” *59(That date is the first Monday in January.) The Board is authorized to recess from time to time, but “it shall complete its duties not later than the third Monday following its first meeting.” G.S. 105-327 (e). It is the duty of the Board of Equalization and Review “to equalize the valuation of all property in the county, to the end that such property shall be listed on the tax records at the valuation required by law; and said board shall correct the tax records for each township so that they will conform to the provisions of this subchapter.” G.S. 105-327(g). Property owners dissatisfied with values equalized by the Board may appeal to the State Board of Assessment. G.S. 105-329. After the Board of Equalization and Review has finished its work, the Board of County Commissioners is without authority to change the records, except to give effect to decisions of the State Board of Assessment; or to correct the name of the taxpayer, or the description of the property, or clerical errors or to list omitted property. They may reassess only “when the supervisor reports that, since the completion of the work of the board of equalization, facts have come to his attention which render it advisable to raise or lower the assessment of some particular property of a given taxpayer.” G.S. 105-330.
The reason why the Board of Equalization is required to act within a fixed time is apparent. The taxing authority must know the value of the taxable property before it can fix a rate sufficient to meet governmental needs. This rate must be fixed prior to September, G.S. 105-339, G.S. 153-120. Having ascertained both rate and tax, the amount due by each taxpayer must be computed, and the tax books delivered to the tax collector on or prior to the first Monday in October, on which day the taxes are due and payable, G.S. 105-345. The taxpayer may obtain a discount by prepayment. If he pays prior to the time his tax liability is ascertained, his payment is credited on his tax liability. Here, plaintiff paid his tax in September and obtained a discount of one percent, as provided by G.S. 105-345(6).
The duty imposed on the Board of Equalization and Review to complete its work within the time prescribed by G.S. 105-327 (e), at least to the extent that authority is given the Board to act ex mero motu, is mandatory. As said by Clark, C.J. in construing a similar statute: “There are some circumstances under which a requirement that a certain act shall be done on a date named may be treated as directory, but that is not possible when the statute conferring a power provides that it shall be performed ‘not later than’ the time specified.” Williams v. Comrs., 182 N.C. 135, 108 S.E. 503; Wolfenden v. Comrs., 152 N.C. 83, 67 S.E. 319; Fromkin v. State, 63 N.W. 2d 332; State v. Johnson, 106 S.E. 2d 353; Annotations, 105 A.L.R. 624.
*60Since the Board of Review was without authority under the Machinery Act to increase the value of plaintiffs property in December, after he had paid the taxes assessed thereon, we must determine whether the general rule has been changed by statutes applicable only to Meck-lenburg County.
Chapter 916, S.L. 1961, is entitled: “AN ACT AUTHORIZING APPOINTMENT OF A BOARD OF EQUALIZATION AND REVIEW FOR MECKLENBURG COUNTY.” The act applies only to Mecklenburg County (sec. 8). Commissioners of that county are authorized to act as the Board of Equalization and Review, or to appoint a special Board of Review. The tax supervisor, or a deputy designated by him, acts as clerk to the Board of Review. The authority vested in the special Board, which the commissioners are authorized to appoint, is substantially the same as the authority given to regular Boards of Review by G.S. 105-327. Section 5 of the 1961 act provides: “The board of equalization and review shall meet at such times and at such places as the chairman of such board may direct, provided, however, it shall complete its duties not later than ten days before the date provided by law for fixing the tax rate for the current year.”
Chapter 281, S.L. 1963, ratified April 23, 1963, has this preamble:
“WHEREAS, pursuant to the provisions of G.S. 105-278, the County of Mecklenburg is revaluing real property for ad valorem tax purposes as of January 1, 1963; and
“WHEREAS, there have been numerous protests or appeals filed by taxpayers with the Mecklenburg County Board of Equalization and Review and it is anticipated that many other appeals may be filed; and
“WHEREAS, it is deemed desirable that the Mecklenburg County Board of Equalization and Review should have sufficient time in which to fully consider all appeals and to make such adjustments as may be deemed fair and equitable:”
The act provides: “The Mecklenburg County Board of Equalization and Review is hereby authorized to continue its sessions for the year 1963 to hear all appeals which may be brought before it upon the assessed valuations of property, and to make any adjustments, whensoever it shall hear the appeal, as of January 1, 1963.”
Defendant relies on the 1963 act to support its position that it could in December, after plaintiff had paid his taxes, increase the appraised value of plaintiff’s property. We are of the opinion that the Legislature did not intend to grant such authority. The preamble clearly indicates that the act was intended to afford the Board of Equalization and Re*61view opportunity to act on appeals by property owners from the assessing authority. The act merely granted this authority. It does not purport to vest the Board with authority ex mero motu to increase the values which the assessor has placed on a taxpayer’s property.
The people have limited the power of the Legislature to enact local or special laws. Our Constitution provides in Art. II, sec. 29: “The General Assembly shall not pass any local, private, or special act * * * extending the time for the assessment or collection of taxes * * If defendants’ interpretation of c. 281, S.L. 1963, is correct, the statute would do violence to this constitutional provision. Everywhere in North Carolina, except in Mecklenburg County, the power of the Board of Equalization and Review to increase the value assigned by the assessors to the taxpayer’s property terminated prior to the time the commissioners were required to levy taxes. Defendants’ contention would authorize the Legislature to enact a special statute extending the time for the assessment of taxes in Mecklenburg County. The statute ought not to receive a construction which would bring it into direct conflict with constitutional prohibitions.
We conclude the Board of Equalization and Review was without authority in December 1963 to increase the assessed value of plaintiff’s property.
Reversed.