The taxes for which refunds are sought were paid by plaintiff-appellee’s assignors for the years 1934, 1935, and 1936. These taxes were excessive because of .the failure of the county auditor of Crawford county, in computing the tax rate, to deduct from the total budget requirements the tax io be derived from moneys and credits in compliance with section 7164, Code, 1935. See Hewitt & Sons v. Keller, 223 Iowa 1372, 275 N. W. 94. In 1934, section 7164 was amended to read as follows:
‘ ‘ Computation of rate. When the valuations for the several taxing districts shall have been adjusted by the several boards *251for the current year, the county auditor shall thereupon apply such a rate, not exceeding the rate authorized by law, as will raise tire amount required for such taxing district, and no larger amount.
“Provided that the county auditor shall, in computing the tax rate for any taxing district, deduct from the total budget requirements certified by any such district all of the tax to be derived from the moneys and credits and other moneyed capital taxed at a fiat rate as provided in section 6985 and shall then apply such rate to the adjusted taxable value of the property in the district, necessary to raise the amount required after the deductions herein provided have been made. ’ ’
The record before us shows that in only 13 counties did the auditor, in computing the tax rate for 1934, 1935, and 1936, deduct the tax to be derived from moneys and credits as required by the above section. In the remainder of the 99 counties, including Crawford, the auditor failed to make this deduction for one or more of the three years in question. Because of this failure taxes were collected in excessive amounts in more than 80 counties. In some of the counties where there was no compliance with section 7164, some refunds of the excesses were made. The record indicates, however, that in most of such counties no refunds were made.
The Forty-eighth General Assembly, after the decision of this court in Hewitt & Sons v. Keller, supra, attempted to legalize the taxes collected in all counties where the auditor did not comply with section 7164, by the passage of chapter 250, Acts of the Forty-eighth General Assembly, reading as follows:
“All taxes levied, assessed, or collected wherein the county auditor in computing the tax rate failed to deduct from the total budget requirements the tax to be derived from moneys and credits and other moneyed capital during the years 1934, 1935, 1936, and 1937, as defined by section seventy-one hundred sixty-four (7164) of the Code, are hereby declared legal and valid.”
This legalizing act went into effect during the pendency of the present suit and was pleaded by appellant Board as a complete defense. By reply, appellee challenged the constitutionality of the act. The trial court h ;ld the legalizing act was not of *252uniform operation in violation of the constitutional provisions hereinafter mentioned, that it therefore constituted no defense to appellee’s suit and ordered the refunds. The Board of Supervisors has appealed. There is presented to us the single question of the constitutionality of the legalizing act.
I. The power to declare legislation unconstitutional is one which courts exercise with great caution, and only when such conclusion is unavoidable. State ex rel. Welsh v. Darling, 216 Iowa 553, 556, 246 N. W. 390, 88 A. L. R. 218; Hubbell v. Higgins, 148 Iowa 36, 47, 126 N. W. 914, Ann. Cas. 1912B, 822. And the presumption in favor of constitutionality is especially strong Avhere the statute, like the one before us, was enacted to promote a public purpose, such, for example, as statutes relating to taxation. 16 C. J. S., page 275, section 99.
II. Appellee claims the act (chapter 250, Forty-eighth General Assembly) is unconstitutional in four respects. The principal contention is that it is not of uniform operation throughout the state, in violation of section 6, Article I, and section 30, Article III, of the state constitution. The trial court so held. Section 6, Article I, provides: “All laAvs of a general nature shall have a uniform operation”. Section 30, Article III, provides: ‘ ‘ The General Assembly shall not pass local or special laws in the folloAving cases: For the assessment and collection of taxes * * * In all the cases above enumerated, * # * all laAvs shall be general, and of uniform operation throughout the State”.
We do not understand appellee to contend that the act in question is a local or special laAV. Is it of uniform operation? That is the vital question. It may at once be conceded that the act does not operate alike upon all citizens of the state. This court has repeatedly held, however, that uniformity, in the constitutional sense, does not depend upon the number of citizens affected or within the scope of operation of the laAV in question. A large amount of legislation is not uniform in the extent of its application. Smith v. Thompson, 219 Iowa 888, 910, 258 N. W. 190; State ex. rel. Welsh v. Darling, supra (at page 559 of 216 Iowa, page 393 of 246 N. W.); McAunich v. Mississippi & M. R. Co., 20 Iowa 338, 343. If the law operates upon every person within the relation or circumstances provided for in the act, the requirement of uniformity is met.
*253It lias been held more than once that a law is of uniform operation throughout the state even though at the time of its adoption its practical application is limited, for example, to a single municipality. See State ex rel. Welsh v. Darling, supra, and cases cited at page 559 of 216 Iowa, page 393 of 246 N. W. Compare State v. Des Moines, 96 Iowa 521, 65 N. W. 818, 31 L. R. A. 186, 59 Am. St. Rep. 381, where a law was held nonuniform because by no possibility could it ever apply to more than one city. In the Des Moines case, however, this court observed, page 526 of 96 Iowa, page 820 of 65 N. W., that “a law which at a given time, operates as to only one bank, company, or society, because there is but one such, but is so framed as to operate on the same conditions, when and where they arise in the state, is a general law, and of uniform operation [citing eases]. This rule is one of general recognition.” (Italics supplied.) Laws which are public in their objects may be confined to a particular class of persons if they are general in their application to the cases to which they apply, provided the distinction is not arbitrary but rests upon some reason of public policy. Hubbell v. Higgins, 148 Iowa 36, 39, 40, 126 N. W. 914, Ann. Cas. 1912B, 822. It is apparent that in passing the act before us the legislature was confronted with important questions of public policy, such, for example, as the raising by taxation of sufficient funds with which to make refunds and pay the considerable expense of computing the amounts to be refunded, and also the extensive litigation that would be apt to result if no curative act were adopted.
It is also- well recognized that the legislature exercises a wide discretion in determining classifications to which its enactments shall be made applicable. State ex rel. Welsh v. Darling, supra, at page 556 of 216 Iowa, page 391 of 246 N. W.; Tolerton & W. Co. v. Iowa Board, 222 Iowa 908, 912, 270 N. W. 427, 429.
Appellee does not argue that the law is not uniform because of any language in the act itself. His entire argument is based on the facts (1) that in 13 of the 99 counties the auditor for the three years in question observed the requirement of section 7164 by deducting the moneys and credits tax while in the remaining counties this requirement was ignored for one or more of the three years, and (2) that in some few counties where excessive *254amounts were collected, refunds were made to some taxpayers. If every county auditor in the state had failed to make the deduction for the years in question, and if no refunds had been granted by any of the counties, then there would be no basis whatever for appellee’s claim of nonuniformity. His contention, in substance, is that a general curative act cannot be passed after advantages have accrued to some citizens before the passage of the act.
The act in question operated in the 80-odd counties'where the auditor failed to comply with section 7164. We hold that the legislature had the power to pass this act, that it was of uniform operation in the constitutional sense and that the distinguished trial court erred in holding to the contrary. We think our conclusion is amply supported by prior decisions of this court.
In an early case, Boardman v. Beckwith, 18 Iowa 292, property had been sold in 1860 for nonpayment of taxes for 1858. No •law was then in force authorizing the levy or collection of taxes for that year. The legislature in 1860 passed an .act legalizing such unauthorized levies. The opinion does not disclose the number of counties in which such levies had been made. The act was held valid and of uniform operation throughout the state. The following observation made in the opinion has been quoted many times throughout the history of this court, page 294 of 18 Iowa:
‘ ‘ The power of the legislature to pass acts of this character, conducive as they are to the general welfare, and based upon considerations of controlling public necessity, is, in our opinion, undoubted. ’ ’
In Von Phul v. Hammer, 29 Iowa 222, it appeared that by the original charter of Newton, no authority was given to levy a sidewalk tax. Under a subsequent act of the legislature, the town amended its charter to include such authority. It was claimed the act violated section 30, Article III, of the state constitution but its validity was upheld. The court makes the following pertinent pronouncement which is a complete answer to appellee’s contention, pages 223 and 224 of 29 Iowa:
*255“It is quite true, however, that by the enactment- of that section, which is a general law of uniform operation, there may result a consequence, to wit, a want of uniformity of city charters, which was one of the evils that the particular clause of the constitution under consideration was. designed to remedy. But the clause itself is not, nor can it by any fair construction be made to be, so far-reaching as to prevent such consequences. For instance, under the general incorporation, law for cities and towns * * * the same power of taxation # * * is given alike to all cities of the same class. But it is quite probable that no- two cities in the state exercise the power in precisely the same manner. Each provides by its own ordinances the manner in which it will exercise the power. And surely it cannot be claimed that all such laws and ordinances are void, under .article 3, section 30, for want of uniformity. Many other illustrations might be given, but they are unnecessary.” (Italics supplied.)
Haskel v. Burlington, 30 Iowa 232, although decided in 1870, is another leading case in this state. Special charter cities, of which Burlington was one, had no power to sell lands for delinquent taxes. A statute was enacted under which the city claimed that right as to taxes delinquent at the time of its passage. It was contended- the statute, because it applied only to special charter cities, was not of uniform operation in violation of the same constitutional provisions which appellee now seeks to invoke. The court held otherwise, saying at pages 236 and 237 of 30 Iowa:
“As such [special charter] cities were few, at the time of the passage of this act, and hence but few cities were affected by its provisions, it is claimed that the statute is. local and special, and has not a uniform operation throughout the State. This position is believed to be unsound. * * *
“So that wherever cities are found, in whatever portion of the State, be they few or many, which were incorporated under special charters, to them the law applies. And it applies to all cities in the State falling within the class specified, and, hence, is not local nor special, but of uniform operation.”
*256Iowa Railroad Land Co. v. Soper, 39 Iowa 112, is probably the leading case in Iowa on the question under consideration. Certain taxing bodies, including the board of supervisors of Carroll county, had levied a tax to' pay certain judgments against them. This court had held the judgment taxes were illegal because in excess of the maximum authorized by law. A taxpayer brought mandamus against Carroll county for the refund of the taxes. The county pleaded a legalizing act similar to the one now before us. The act was held constitutional and of uniform operation throughout the state even though a comparatively few taxing bodies had levied and collected the excessive taxes and the legalizing act was operative only in those taxing districts. The court followed the earlier cases above mentioned in holding that the curative statute operated upon a particular condition, that is, in all taxing districts where before the passage of the act there had been levied special judgment taxes in excess of the maximum allowed by law. In those districts, the consequences named in the act followed, namely, such taxes were legalized and validated. The law was held general, not because it operated uniformly upon every person in the state, because clearly it did not, but because it was uniform in its operation upon all persons in the taxing districts where the excessive levy had been exacted. The court says at page 116 of 39 Iowa:
“It is very clear that if every municipal corporation within the State had levied taxes to pay judgments, which levies had been in excess of the maximum amount fixed by law, the act under consideration would have applied to them all alike. In other words, if the condition described in the act had existed in every corporation m the State, the act would have been applicable to them all. ’ ’
In Chicago, R.I.&P.Ry.Co. v. Independent District of Avoca, 99 Iowa 556, 68 N. W. 881, the Avoca school district and four other school districts in the state levied school taxes which were void under a decision of this court because not made within the time fixed by statute. The railroad sought to recover the taxes *257paid to the Avoca district. The district pleaded a curative act applicable to it but not to the other four districts. The constitutionality of the act was upheld. We cite this decision as indicative of the extent to which this court has gone to sustain legalizing acts.
The above cases are early ones. None of them, however, is an isolated decision; they have all been repeatedly cited with approval by this court even in very late pronouncements. There are three recent eases in Iowa which to our minds present practically the identical situation, at least on principle, to that now before us. An emergency tax levy made in some but not all counties of the state had been held illegal because of a defective title of the authorizing statute, known as the local budget law. (See Chicago, R.I.&P.Ry.Co v. Streepy, 207 Iowa 851, 224 N. W. 41.) A few days after this court decision the legislature passed an act legalizing the tax in the counties where it had been exacted. It was strenuously contended that the act was invalid on the identical grounds now urged upon us by appellee. In two decisions of this court, after a review of earlier eases including Haskel v. Burlington and Iowa Railroad Land Co. v. Soper, the curative act was upheld.. See Chicago, R.I.&P.Ry.Co. v. Streepy, 211 Iowa 1334, 236 N. W. 24, and Chicago, R.I.&P.Ry. Co. v. Rosenbaum, 212 Iowa 227, 231 N. W. 646. In the Rosenbaum case the court says, at pages 236 and 238 of 212 Iowa, pages 650 and 651 of 231 N. W.:
“The legalizing act has no effect whatever,^except upon some municipality as defined by the Budget Law, which had made an assessment and levy under color of authority derived from Section 373 of the Code. * * * There is no lack of uniformity in its operation. It has been the universal holdings of this court that a statute of this kind and' character is not violative of the aforesaid sections of the Constitution. See Boardman v. Beckwith, 18 Iowa 292; Iowa Railroad Land Co. v. Soper, 39 Iowa 112.”
Counsel for appellee, in both oral and written argument made strenuous efforts to distinguish the above decisions, particularly the Iowa Railroad Land Company case in 39 Iowa and the Rock *258Island Railroad cases in 211 and 212 Iowa, 236 and 231 N. W. The argument is that the illegality in those cases was in the levy of the tax by taxing bodies rather than in the computation of a tax rate by such a ministerial officer as the county auditor — that the legislature can legalize excessive levies by taxing bodies because it could have authorized such levies in the first instance, but is powerless to cure the error of county auditors in computing a higher tax rate than authorized by law.
Of course, it is true that a legalizing statute can cure only such action as the legislature could have authorized. Nevertheless, we cannot agree that counsel’s attempt to distinguish the' above decisions is sound. What counsel overlook is that the act in question operates with fully as much uniformity throughout the state as did the acts held valid in the Iowa Railroad Land Company and Rock Island Railroad eases. It is true the act now before us does not attempt to legalize an excessive levy made by a taxing body, but a mistake of the auditor in computing the tax rate. But the legislature has just as much power to prescribe the method by which auditors are to compute tax rates as to authorize taxing bodies to make levies. Let us assume that the taxpayers of Crawford county by reason of the failure of the auditor to deduct moneys and credits tax in computing the tax rate for 1936 paid in excessive amounts totaling $5,000. Now let us assume that the Board of Supervisors had made an excessive levy of $5,000 for some purpose not authorized by law. Appellee concedes, as indeed he must under the decisions above referred to, that the excessive levy could be legalized, even though as a consequence taxpayers of Crawford county would be forced to pay a higher tax than in some county where the excessive levy had not been made. It seems to us that the practical effect of collecting $5,000 because of an excess levy and collecting $5,000 excess because of the failure of the auditor properly to compute the tax rate is identical. Also, that the results of curative acts curing the two forms of illegality are identical so far as uniformity of operation is concerned.
We have given careful consideration to the authorities cited by appellee in support of liis claim of nonuniformity in the operation of the act under consideration. None of them is in *259point nor has but remote application to the present controversy. Only two of the Iowa cases cited by appellee anywhere in his briefs involve curative acts: Independent School Dist. v. Burlington, 60 Iowa 500, 15 N. W. 295, and Cedar Rapids Water Co. v. Cedar Rapids, 118 Iowa 234, 91 N. W. 1081. In each of these two cases the city had enacted an illegal ordinance. The legislature attempted by a local or special law, which did not profess to be of uniform operation throughout the state, to cure this illegality. The court in each case rightly held that the law was invalid as a local or special law. It was not necessary in either ease to consider the question whether the act was of. uniform operation throughout the state. The distinction between such cases and a case involving a general statute enacted in the public interest, such as the one now before us, is readily apparent.
III. The findings of the trial court indicate that the principal ground on which it held the act unconstitutional is that it was nonuniform in operation. Appellee contends, however, the act violated the constitution in three other respects. The second attack upon the act is that it is in effect a delegation by ratification to county auditors of the legislative power of levying taxes in violation of section 1, Article III, of the state constitution pertaining to distribution of powers between the three branches of government. It is to be noted that this contention is somewhat inconsistent with appellee’s argument that the type of illegality sought to be cured by the present act differs from that involved in the decisions reviewed in the preceding division of this opinion. His claim at this point is that what really resulted from the error of the auditors was an illegal tax levy which he concedes, in an attempt to avoid the force of our own decisions, the legislature had the power to cure.
The attorney general concedes that tax levying, which is legislative, cannot be delegated to county auditors. We do not agree that a legalizing act amounts 1o a delegation of the power of taxation to a county auditor merely because it places its stamp of approval on the erroneous action of more than 80 county auditors of the state in the computation of the tax rate. Undoubtedly, as we have previously observed, the legislature has the power from time to time by general statute to change the method to be *260used by county auditors in computing tax rates. Indeed, the legislature by amending section 7164 changed the existing method of computing the rate by providing for the deduction of the tax on moneys and credits. It was the violation of this prescribed method that led to the curative enactment. It is elementary that “A curative act may cure or legalize any act which the general assembly could, as an original question, have authorized.” Chicago, R.I.&P.Ry.Co. v. Rosenbaum, 212 Iowa 227, 231, 231 N. W. 646, 648. Since the legislature has the power in the first instance to provide for the method of computing tax rates by auditors, after the lawful method had been ignored and an erroneous computation used, it had the power to legalize such error by the enactment now before us.
IV. It is next contended that the curative act amounts to a denial of the equal protection of the laws and grants to citizens in the counties where the auditor made the required deduction for moneys and credits, and in counties where refunds were made, privileges and immunities which were denied to taxpayers in the counties in which the curative act was operative and no refunds were made, in violation of section 1 of the fourteenth amendment to the federal constitution and section 6, Article I, of the state constitution. Appellee cites but two Iowa cases (along with one case from another jurisdiction) in support of this contention: State v. Garbroski, 111 Iowa 496, 82 N. W. 959, 56 L. R. A. 570, 82 Am. St. Rep. 524; and Hubbell v. Higgins, 148 Iowa 36, 126 N. W. 914, Ann. Cas. 1912B, 822. Neither of these cases is applicable to the present controversy. They both involve the reasonableness of legislative classification, the Garbroski 'case holding such classification was unreasonable, and the Hubbell case upholding the classification there made by the legislature.
The argument in support of this attack is practically the same as the argument in support of appellee’s claim that the act is not of uniform operation. What we have said on the subject of uniformity and the authorities discussed in division II of this opinion sufficiently answer this contention. If the legislature had the right, as we hold it did, to enact this statute which was applicable in all of the 80-some counties where there *261was no compliance with the law in computing the tax rate, no taxpayer in any of those counties can be heard to complain because of claimed denial of privileges or immunities or equal protection of the law.
V. Appellee’s remaining claim of unconstitutionality is that the act violates section 7, Article VII, of the state constitution which requires that every law which imposes, continues, or revives a tax must distinctly state the tax and the object to which it is to be applied and it shall not be sufficient to refer to any other law to fix such tax or object. The basis for the argument' in support of this contention is that the obvious effect of chapter 250, Acts of the Forty-eighth General Assembly, is an attempt to levy a tax. It is substantially the same argument that is made in support of the somewhat inconsistent claim that it constitutes a delegation to the county auditor of the power to levy a tax. This question was passed on contrary to appellee’s contention in Chicago, R.I.&P.Ry.Co. v. Rosenbaum, supra. The court there recognizes under the authority of Youngerman v. Murphy, 107 Iowa 686, 76 N. W. 648, and Fevold v. Board of Supervisors, 202 Iowa 1019, 210 N. W. 139, that a statute which merely delegates to taxing bodies the power to tax but which does not itself impose the tax is not such as comes within the meaning of this section of the constitution. (See page 235 of 212 Iowa, page 649 of 231 N. W.) The court squarely rejects the contention that the legalizing act there under consideration, which was very similar to the one now before us, imposed, continued, or revived a tax. While we are not to be understood as holding that the act in question delegated the power to tax, we do hold that it did not impose, continue, or revive a tax, and therefore this constitutional provision is not applicable.
Some other questions have been argued. We have given them all careful consideration. The foregoing is determinative of the case. We are unable to find that chapter 250, Acts of the Forty-eighth General Assembly, is such a clear and palpable violation of the constitutional provisions upon which appellee relies that we can conscientiously hold it to be invalid. Since our conclusion is contrary to that reached by the trial court, the judgment is reversed. — Reversed.
*262Hale, C. J., and Mitchell, Sager, Bliss, and Oliver, JJ., concur.
Miller, Stiger, and Wennerstrum, JJ., dissent.