Opinion by
Mr. Justice Stewart,By Act of Assembly approved June 27, 1913, P. L. 639, entitled “An Act levying a tax on anthracite coal and providing for the collection and distribution of the same,” every ton of anthracite coal of the weight of 2,240 pounds avoirdupois, prepared for market within the State, is made subject to a State tax of two and one-half per centum of the value thereof, the same to be settled and collected as provided by law for other taxes. By the second section of the act every operator of anthracite mines is required to report to the auditor general in the month of January the number of tons of coal mined by such operator within the calendar year next preceding, and the value thereof prepared for market. Complying with this requirement, but protesting against its liability to make such report or to pay such tax, the appellant company filed with the auditor general on 31 January, 1914, a report showing the anthracite coal mined and prepared by it for market during the period beginning 28th June, 1913, and ending 31st December, 1913. Thereupon, 29th June, 1914, the auditor general settled an account against appellant which was approved by the State treasurer, in which tax to the amount of $7,-*137792.86 was charged against appellant. From this settlement an appeal was taken to the Court of Common Pleas of Dauphin County, the ground of complaint being that the act authorizing the collection of such tax was unconstitutional and void. The case by agreement was heard by the court without the intervention of a jury. The determination reached was that the act was constitutional and effective, and that the account in question had been properly settled. Judgment was accordingly rendered in favor of the Commonwealth and against the defendant for the amount of the tax. The present appeal is from the judgment so entered, and the same questions are raised here as were presented and considered in the court below. If we should not allow so wide a scope to the inquiry as was given it in the court below, and was assumed upon the argument to be necessary to its determination, the reason will be made apparent as we proceed.
The appeal challenges the constitutionality of the act referred to. One ground on which the challenge rests is that the act violates Section 1, Article IX, of the Constitution, which directs that “all taxes shall be uniform upon the same class of subjects within the territorial limits of the authority levying the tax,” inasmuch as it makes artificial and arbitrary distinction and discrimination between anthracite and bituminous coal, subjecting the former to tax for public purposes and not the latter. The fact that the act does make distinction between the two commodities is patent, and the one question we have to deal with is whether the distinction thus made rests upon such substantial difference as makes either variety a proper subject of this particular exclusive legislation. If this question can be answered in the affirmative, it must follow that the act is not open to the objection urged; for while it does subject to taxation but one of the two varieties of coal, if the variety taxed so differs from that not taxed, in respect to matters proper for consideration in the laying of the tax for *138public revenue as to make exclusive legislation for tbe former reasonable and not arbitrary, it may properly be put in a class by itself for sucb purpose, and tbe legislation with respect to it then becomes general and not special, since it operates uniformly upon all within tbe class. If this result be reached in our inquiry, it must follow as well that tbe tax here prescribed is not discriminatory but uniform, in the sense in wbicb that word is used in tbe Constitution.
In determining whether legislative classification is special and discriminatory regard must be bad to tbe purpose for wbicb tbe legislation is designed. Differences wbicb make classification for some purposes proper, may furnish no reasonable basis for classification for other purposes, it is their relation to tbe end proposed by tbe particular legislation that determines whether classification is warranted. That differences real and substantial exist between anthracite and bituminous coal sucb as amply justify their separate classification for certain purposes, is without question. While both are natural products and tbe chief ’use of each is tbe same — tbe development of beat by combustion — yet they are distinguishable in so many ways, not only in their efficiency, but in respect to conditions under wbicb they are found, conditions under wbicb they are mined, and tbe processes by wbicb they are severally made marketable, that if both were to be subjected in all respects to tbe same legislative requirements, it would result in embarrassing each by imposing upon both regulations and restrictions entirely proper and necessary in tbe case of one but wholly unnecessary and oppressively burdensome upon tbe other. That tbe constitutional restraints and limitations upon legislative power were never intended to work sucb unequal and inequitable results is apparent, and so whenever it has occurred that conditions in respect to one variety of coal and not tbe other, called for specific legislative action with respect to it, tbe legislature has without question or hesitation, for tbe particular pur*139pose before it, placed the variety calling for the legislation in a class by itself and legislated with respect to it to the exclusion of the other. Our several statutes regulating the operation of coal mines, the employment of labor therein, the standard weight of each variety of coal, and distinguishing between the two varieties in many ways, all show this; but it will be found upon examination that whenever distinction is made between the two it is based upon a substantial difference, that is, one so marked as to call for separate legislation; and further, that in every case there is correspondence between the difference which is made the basis of the classification and the object and purpose of the statute. The case of Durkin v. Kingston Coal Company, 171 Pa. 193, is a fair illustration. The fact that the statutes referred to have beén upheld as constitutional can be of no significance in our present inquiry except as we find like conditions here; first, a classification resting upon a difference between the two varieties peculiarly requiring it to the end that injustice and inequality might be avoided; and second, a correspondence between the difference which is made the basis of the classification and the design and purpose of the proposed or enacted legislation; for, except as there be correspondence, the distinction is capricious. The right of the legislature to classify subjects within its jurisdiction for the purpose of enacting laws is unquestioned; so too is its right to determine what things shall be subject to tax for public purposes; but in both instances the right can be exercised only in subordination to certain constitutional restrictions. The legislature may no longer by arbitrary discrimination subject certain property to taxation, and exempt other property of the same kind and class and similarly situated from an equal burden. It may discriminate between two of a class in this respect by method of classification, but it can do this only when a substantial difference exists operating to make the distinction just and reasonable, and the legislation based *140thereon agreeable to something more than legislative notion of expediency. It must rest on a difference which bears a natural, reasonable and just relation to the act. in regard to which the classification is proposed; or, as stated by Mr. Justice Brewer in Gulf, Colo. & Santa Fe Ry. Co. v. Ellis, 165 U. S. 150, and quoted approvingly by Sterrett, C. J., in Juniata Limestone Co., Ltd., v. Fagley, 187 Pa. 193, 197, “it must appear not only that a classification has been made, but also that it is one based upon some reasonable grounds, some difference which bears a just and proper relation to the attempted classification, and is not a mere arbitrary selection.” It is constantly to be borne in mind that the right of classification is allowed in order to avoid or- correct inequalities, never to create them. It is quite true that the details of the legislation with respect to taxation for public purposes, and the exemptions proper to be made, rest primarily within the discretion of the legislature, and in classifying subjects for taxation it cannot be required to state the grounds of the classification; but it is no less true that the action of the legislature in any particular case is subject to judicial revision to the extent of seeing that the classification adopted rests upon real distinctions, not artificial or irrelevant ones, in the subjects classified, and has not been adopted for the purpose of evading any constitutional prohibition, When upon judicial revision it clearly appears that the classification adopted rests upon no substantial difference in the subject, that, whatever, the difference, it bears no correspondence to the end and object of the act, the right and duty of the court to assert and maintain the supremacy of the Constitution, even though it means the defeat of the legislation, is too apparent to invite argument.
Now upon what difference between these two varieties of coal can this discrimination which has for its object the subjection of the anthracite variety to taxation to the exclusion of the bituminous, rest?. That they belong to *141one general class, are closely and intimately related both in respect to origin and nse, is not open to dispute. Differences there are as we have before indicated, and where-ever, because of these, the same legislation governing both would be unjust or oppressive to either, classification has properly been resorted to; but neither singly nor in combination do these differences suggest a reason why one should be taxed and not the other, whether regard be had to diversity in inherent or incidental qualities, diversity in commercial uses, in method of production, or even incompatibility or inconvenience in adopting the same method of taxation for both. A single difference as a basis of classification is suggested in the brief of argument on behalf of appellee. It is thus stated in the brief submitted, “The court, of its own knowledge, knows that the price of anthracite coal ranges from four to eight dollars per ton, and the price of bituminous coal ranges from one to two dollars per ton. The reason is that anthracite coal is found almost exclusively in the State of Pennsylvania. The United States government has engaged in litigation to separate the coal carrying roads from the great coal corporations, notably the Beading Coal and Iron Company, upon the theory that there is an illegal combination or trust. Proof of these facts is not necessary. The court only needs to find from human experience, some possible reason which induced the legislature to make the classification.” There may be something herein implied that would indicate a difference beyond that of market price in the two varieties, but certainly nothing beyond it is expressed. It may be that what is implied would be a proper consideration in determining a line of public policy, but we are not here dealing with questions of public policy, but with a single question of constitutional restriction upon legislative power to tax for public revenue. The one reason expressed is so wholly inadequate as a basis of differentiation that we, need take no time in discussing it. It involves the proposition that it *142is competent for the legislature by process of classification on the basis of market value, to throw the entire burden of the tax upon a selected few of an entire class, undistinguishable in its members in any other regard. And yet on this very crux of the case we have but this one suggestion of difference as a basis for classification; namely, market price or value. Were such rule to be recognized the legislature would be invested with a discretion as wide and unrestrained as it originally exercised, but which the people by their constitution declared should be confined within certain fixed limitations, one of which was that taxation should be uniform upon subjects of the same class. To allow the legislature arbitrarily to determine the class would be to defeat the very object of the constitutional restriction, and make taxation an instrument not of revenue but of monopoly.
And so we recur to the main and only inquiry, what difference is there between anthracite and bituminous coal that makes the one, when prepared for market, a proper subject for taxation, and not the other? Our answer must be, after the most careful consideration of the question, in the light of the findings of the learned judge who heard the case in the court below, and the arguments advanced on the part of the Commonwealth, that we discover none. Not only so, but as one result of our inquiry we find that the classification adopted instead of tending to promote equality in taxation must necessarily have a contrary effect, to the manifest prejudice of the interest subjected to the tax. Take but one illustration. It is a fact found by the learned judge of the court below, not excepted to, that of the total annual tonnage of anthracite coal, amounting to upwards of ninety-one millions of tons, forty per cent, is sold in keen competition with bituminous coal in the fuel market. Here then we have two commodities in active competition, to the extent of nearly the one-half of the total production of one of them, in the open market; one taxed two and a half per cent., ad valorem, on every ton *143produced, and the other untaxed. What effect this discrimination would have on the anthracite industry we do not know; it may be that the tax imposed is so moderate in amount that it would not cripple it in competition with the bituminous industry; but that is a matter aside from the present inquiry, it is the principle that concerns us. The unrestrained power to tax is the power to destroy, and if the legislature may impose a tax of two and a half per cent., ad valorem, upon either commodity as distinguished from the other, we know of no constitutional restraint that would prevent it from increasing the tax to any limit it might see fit, even to the total destruction of the industry taxed. The mere fact that competition in thé general market exists to the extent indicated between these two products, ought to be in itself convincing that their separate classification for the purpose of taxation rests upon a purely arbitrary basis; and when this is followed by a tax upon one from which the other is exempt, the conclusion would seem inevitable that the whole scheme is defiantly repugnant to the constitutional requirement that all taxes shall be uniform upon the same class of subjects. Referring to this provision in our Constitution, Mr. Justice Paxson, speaking for this court in Appeal of Fox and wife, 112 Pa. 337, said (p. 352) : “This portion of the Constitution is too important and valuable to be overridden by the legslature or frittered away by judicial construction. It was intended to, and does sweep away forever the power of the legislature to impose unequal burdens upon the people under the form of taxation. The evils which led up to its incorporation into the organic law are well known. The burden of maintaining the state has been, in repeated instances, lifted from the shoulders of favored classes and thrown upon the remainder of the community. This was done by means of favoritism and class legislation. Article IX of the Constitution was intended to cut out this system by the roots, and we shall have no more of it if the legislative and judicial depart*144ments of the government perform their full duty in giving effect to that instrument. The taxing power of the State is great and searching. Within the limits of the Constitution it is bounded only by the necessities of the State and the will of the people. This must be so or the State might be without the means to sustain itself; to repress aggression from without, or to suppress disorder within. So long as it lays its burdens upon all alike, there is hardly a limit to this power. It may take from the people what its necessities demand. The power of the State is conceded to select its subjects of taxation. It may tax mortgages, or it may omit to tax them. But this tax, upon whatever laid, must be uniform. It cannot tax A on his mortgages or horses and exempt B from a like tax —. It is perhaps vain to expect that any system of taxation shall produce exact uniformity. It is however both reasonable and possible to levy the taxes in such a manner that substantial justice and uniformity shall be the result.” This was said after the experience of a decade under the working of what was then the new Constitution. Subsequent experience has furnished no reason for abating anything from what was then said as to the importance and value of the constitutional restriction upon the power of the legislature in the matter of taxation for public purposes, and the duty of the courts to withhold their sanction when, as in this case, the restriction has been plainly and unmistakably disregarded.
Another feature of the act to be remarked upon as further illustrating its repugnancy to constitutional provisions is to be found in section 5 of the act which directs that each county shall receive from the State treasurer, for the use of the several cities, boroughs, and townships thereof, one-half of said tax collected;from operators in said county; and that the treasurers thereof shall, within thirty days thereafter, pay over the same to the treasurers of the several cities, boroughs and townships in said county pro rata according to their respective popu*145lations as shown by the last preceding United States census.
It is important in this connection to recall some of the more significant facts found by the court below. These are: that anthracite coal, the subject of the proposed tax, is found in but nine counties of the State, while bituminous coal is found and mined in twenty-four; that in 1913 the total anthracite tonnage was 91,626,956 tons and the total bituminous tonnage was 173,030,064 tons; that the tax imposed by the act upon the anthracite exclusively would, if enforced, amount to several million dollars annually, and the one-half thereof returned to the counties in trust for the several boroughs, cities, and townships thereof according to population would in some cases give to the municipality more than the entire tax raised therein for municipal purposes, and in a great many cases would approximate the total amount raised for municipal purposes, and would bestow upon many boroughs and townships which do not now and never have contained a pound of coal deposited within their limits large sums of money annually for the conduct of their municipal affairs, or for such municipal expenditures as such municipalities may see fit to make.
Keeping in mind that the one great purpose of legislative classification is to avoid the inequalities that would necessarily result from subjecting all the members or subjects of a natural class to uniformity of rule, is it not apparent that, whatever the purpose of this act, its certain effect would be not only an unjust and unwarranted discrimination in levying the tax, but a like unjust and unwarranted discrimination in its disbursement? Here we have a tax imposed yielding a revenue twice as large in amount as the State’s requirements, and, for some undisclosed reason, the one-half of the total paid into the state treasury is directed to be paid over to the treasurers of the nine anthracite producing counties to be divided among the several municipalities therein. It is no less difficult to discover a substantial reason for this *146than it is to discover a substantial reason for putting the two varieties of coal in separate classification. We are here again left to conjecture. The explanation attempted by the Commonwealth in its effort to sustain the act may be the correct one, but, if so, it must prove fatal to the act. We quote from the brief of argument submitted, “Great cities have been developed by the coal industry. The development of these cities has imposed great burdens upon the counties and resulted in large issues of bonds by both cities and counties. The time is fast approaching when the cities, because of the wealth of the coal becoming exhausted, will not be able to meet their oligations as they are now able to meet them. The exhaustion of the coal will impoverish the municipalities. To return to them the tax which comes from the coal mined in the county is fair and wise. The City of Carbondale now faces a great problem not only because of impoverishment but destruction, because the mines beneath it are on fire.” Again, “The very fact of the mining operations themselves being so hazardous and annually resulting in awful accidents by which large numbers of wives are made widows, and great numbers of orphans and cripples are thrown upon the communities to support by taxation, demonstrates the necessity for a return of taxation to the communities and poor districts from which this wealth of coal is being removed.” Here we have the only explanation of this unique legislation that is advanced. If it be accepted as correct, then it follows that this 5th section of the act transcends the power of the legislature, since it is an appropriation resting wholly and exclusively upon charitable and benevolent considerations affecting certain particular communities. Section 18 of Article III of the Constitution provides that no appropriation...... shall be made for charitable or benevolent purposes to any person or community. In view of this express prohibition we hardly think that it was dread of such dire consequences here foretold as awaiting the an*147tbracite industry of the State, or newly awakened sympathy for the unfortunate miner and his dependents, that inspired this legislation. And yet, we are unable of ourselves to suggest any other explanation. It is argued that inquiry in regard to the purpose of the legislation is irrelevant since the constitutional provision that taxation shall be uniform applies only to the levy and assessment of the tax, and not to its expenditure or distribution. In one sense this is quite true; in another it is wholly incorrect. Conceding the uniformity of the tax as laid, is such uniformity preserved when by the same act that authorizes the tax it is provided that one-half of the amount so realized shall be paid over to certain favored communities? What difference can it make that the great bulk of all of the tax was derived from the nine counties in which these particular communities or municipalities are found? That circumstance gives them no claim for compensation. While the tax is paid in the first instance by the producers, ultimately it is paid by the consumers, and by far the greater part of the burden imposed must be borne by subdivisions which are denied participation in the extra fifty per cent. Had the tax been general, that is to say, upon both anthracite and bituminous coal, and had the act provided that one-half of the sum realized should be returned to the counties producing the bituminous, would anybody contend that such legislation would not offend against the constitutional requirement that taxation must be uniform? And yet that is what in effect is done here. A tax is laid on anthracite coal which consumers throughout the State must pay, those residing in the anthracite counties equally with those outside, but, to relieve those residing within from their full share of the burden, one-half of all that is paid, is to be returned to the municipalities in which they and producers are taxable, and to this extent they are relieved from local taxation. A still more flagrant violation of the rule requiring uniformity of taxation is seen in the fact found that in a great many cases *148the tax would be distributed to boroughs and townships which do not now and never had a pound of coal within their limits, thus exempting them wholly from taxation. When the necessary effect of the legislation is to create inequality of burden as we here see it, are those complaining of the injustice to receive no other answer than that while the Constitution promises them equality in the matter of the taxation, because it failed to place restriction upon the legislature’s right to distribute the tax it collects, therefore the purpose of the legislation is not to be inquired into? If constitutional requirements are to be circumvented by such simple and easy process of reasoning, the question may yet be asked derisively of the Constitution, what is all this worth?
The act in question is assailed on still other grounds than those we have discussed. Were we in any doubt as to the correctness of our conclusion that the act is in plain, open and palpable disregard of the constitutional requirement that all taxes shall be uniform upon the same class of subjects, it would be our duty to give like consideration to these other grounds of attack; but with the unconstitutionality of the act already determined on one wholly adequate ground, discussion of the other objections urged is unnecessary.
For the reason stated the judgment of the court below is reversed, and judgment is now entered for the defendant.