243 U.S. Argument for Plaintiff in Error. dictates, or that he is not of sufficient intelligence to sell his labor without the paternal guidance of a legislative majority. The law upon its face refutes the contention that it is a health law, or that the recitals of the act in § 1 thereof were deemed true by the legislature. The legislative declaration of necessity, even if the act followed such declaration, is not binding upon this court. Coppage v. Kansas, 236 U. S. 1; Minnesota v. Barber, 136 U. S. 313; Powell v. Pennsylvania, 127 U. S. 678; Yates v. Milwaukee, 10 Wall. 497. The law is not a ten-hour law; it is a thirteen-hour law designed solely for the purpose of compelling the employer of labor in mills, factories and manufacturing establishments to pay more for labor than the actual market value thereof. It is based upon economic grounds exclusively. The provision for overtime at time and onehalf the regular wage robs the law of any argument that might be made to bring it within those grounds that justify an exercise of the police power. Freund, Police Power, §§ 316, 318. The right of the legislature to regulate wages is denied in Street v. Varney Electrical Supply Co., 160 Indiana, 338, and People v. Coler, 166 N. Y. 1. These decisions are not affected by Atkin v. Kansas, 191 U. S. 207, and Heim v. McCall, 239 U. S. 175, which relate to hours of labor in public employments. See also Low v. Rees Printing Co., 41 Nebraska, 127, and Wheeling Bridge & Terminal Ry. Co. v. Gilmore, 8 Ohio Cir. Ct. Rep. 858. Insufficiency of wage does not justify legislative regulation. The wage has no bearing upon health. Society may not force the employer to pay wages sufficient to support the employee upon the scale of his desire. But this law goes further, fixing the amount arbitrarily. In this case the employee was receiving a regular wage of 40 cents per hour, on its face a living wage, and there was no basis for an arbitrary demand that he be paid 60 cents per Argument for Defendant in Error. 243 U. S. hour for three hours of his time. The effect is to take money from the employer and give it to the laborer without due process or value in return. Although the terms of employment are more important than the selection of the employee, even the right to select cannot be invaded by state dictation. Adair v. United States, 208 U. S. 161; Coppage v. Kansas, 236 U. S. 1; Chicago, Burlington & Quincy Ry. Co. v. McGuire, 219 U. S. 549. The Oregon act discriminates against plaintiff in error, denying the equal protection of the laws. Atchison, Topeka & Santa Fe. Ry. Co. v. Vosburg, 238 U. S. 56; Cooley Const. Lim., 7th ed., p. 560. The provision for extra wages does not aid in the enforcement of the law as an hours-of-service law. The commingling of unlawful methods of execution with a lawful purpose may make an act unconstitutional as effectively as may an unlawful purpose. Coppage v. Kansas, 236 U. S. 1. The fixing and execution of the overtime pay is an unconstitutional means. Furthermore, it has no reasonable tendency to enforce the declared purpose (distinguishing Commonwealth v. Riley, 210 Massachusetts, 394; s. c., 232 U. S. 671). The penalty theory is untenable. It involves penalizing an employer for doing the very thing the law authorizes, since the act itself permits employment beyond the ten hours. The purpose and scope are fixed by § 2 where the time and overtime provisions appear together. The penalty for violating that section is provided by § 3, is complete in itself, and uniform for every violation of the act. Penal laws should be strictly construed; a court has no province to superadd a penalty by mere implication. Black on Interpretation of Laws, 2d ed., pp. 455, 471. The act being unconstitutional in a vital part must fail as a whole. Low v. Rees Printing Co., 41 Nebraska, 127. . Mr. Felix Frankfurter, with whom Mr. George M. Brown, Attorney General of the State of Oregon, and Mr. J. O. 243 U. S. Argument for Defendant in Error. Bailey, Assistant Attorney General of the State of Oregon, were on the briefs, for defendant in error: The law is an hours law, not a wage law; the provision for overtime work and extra pay being merely to allow a limited and reasonable flexibility in time of unusual business pressure. The conditions in Oregon, which must be considered in passing on the law, show that this must be so since over 93 per cent. of employers find it unprofitable to employ men beyond ten hours at normal pay. Such provisions for higher rates for overtime are common in the regulation of hours, as is shown by trade agreements in this country and in England. They are necessary to preserve the regulation. The issue concerning the validity of the law presents the familiar case of application and delimitation of accepted principles. The liberty of the Fourteenth Amendment is set up against the police power of a State. The boundaries must be drawn in each specific case, not by resort to theory and assumption, but in the light of experience, granting to the legislature the function of discerning, detecting and remedying the evils which may be obstacles to the "greater public welfare" (Rast v. Van Deman & Lewis Co., 240 U. S. 342) and upholding its judgment if in the light of experience the judgment seems not arbitrary or wanton. Experience in England most strikingly dispelled the old theoretical opposition to limitation of the hours of labor and the preference for unfettered individual competition as an economic principle. The matter has now come to be looked on no longer as a mere contest between capital and labor, but as a concern of the State as an organic whole. The question, therefore, is not whether the State can regulate hours of labor in modern industry, but what evils are manifest, and what tendencies are disclosed, that present a reasonable field for legislative repression; what remedies are available that present a reasonable field for legislative encouragement. Argument for Defendant in Error. 243 U.S. This field of reasonable action is the State's police power. See Holden v. Hardy, 169 U. S. 366. In Lochner v. New York, 198 U. S. 45, the state authority in the specific instance was denied because no reasonable relation was discernible to the majority between a ten hour law for bakers and the public welfare. This judgment was based upon a view of the nature of the baker's employment beyond ten hours as known "to the common understanding" Id. 59. See Hours of Labor and Realism in Constitutional Law, 29 Harv. L. Rev. 353. It is now clear that "common understanding" is a treacherous criterion both as to the assumptions on which such understanding is based, and as to the evil consequences, if they are allowed to govern. Pound's Liberty of Contract, 18 Yale L. J. 454, 480, note 123; 2 Ely's Property and Contract, 662, 674-5. The subject is one for scientific scrutiny and critique, for authoritative interpretation of accredited facts. To this end science has been devoted all over the world. Particularly in the last decade science has been giving us the basis for judgment by experience to which, when furnished, judgment by speculation must yield. This is precisely what Holden v. Hardy, supra, looked forward to. The insight expressed in that case has now been amply justified by experience. What in 1898 presented a specific, and apparently, exceptional instance the poisoning of the human system through long hours of labor in mines, and the implications of this evil to the general welfareis now disclosed to be of far wider and deeper application. It is now demonstrable that the considerations that were patent as to miners in 1898 are to-day operative, to a greater or less degree, throughout the industrial system. It is to this body of experience that the court's attention is invited. It is a mass of data that, partly, was not presented in cases like Lochner v. New York, supra, but mostly could not have been before the court, because it was not heretofore in existence. Inasmuch as the application of the contending principles must vary with the facts to which they are sought to be applied, of course new facts are the indispensable basis to the determination of the validity of specific new legislation. People v. Schweinler Press, 214 N. Y. 395, 412. The knowledge obtained by the increasing study of industrial conditions is back of the State's policy, as expressed by the legislature, and sustained by the courts of Oregon. These are facts of common knowledge of which this court will take judicial notice. These facts, we submit, conclusively establish that Oregon was exercising a reasonable judgment as to the public welfare in passing its ten-hour law; and so exercising a reasonable judgment it acted within its rightful and constitutional sphere. The place at which it chose to draw the line was peculiarly for the discretion of its legislature. It is sufficient for the present that the line as now drawn-ten hours a day-is not an unreasonable line. Miller v. Wilson, 236 U. S. 373, 382; People v. Klinck Packing Co., 214 N. Y. 121, 128; State v. Bunting, 71 Oregon, 259, 273. [In support of the argument counsel's brief presented an extensive systematic review of facts and statistics dealing with the effects of overtime upon the physical and moral health of the worker and so upon the vitality, efficiency and prosperity of the nation, with additional references to experiences and results abroad since the outbreak of the European War. The good effects following regulation and the extent of regulation as shown in American and foreign legislation were also indicated.] MR. JUSTICE MCKENNA delivered the opinion of the court. Indictment charging a violation of a statute of the State of Oregon, § 2 of which provides as follows: "No person shall be employed in any mill, factory or |