parent is no longer under legal obligation to support him. On the other hand, the parent is usually under a legal obligation to support his minor children. When a child who is physically and mentally able to take care of himself voluntarily abandons the parental roof and leaves its protection and influence and goes out to fight the battle of life on his own account the parent is no longer under legal obligation to support him. (Hunt v. Thompson, 3 Scam. 179.) If a boy has attained an age at which he is capable of supporting himself, neither justice, reason nor the law requires the parent to maintain him in idleness. Emancipation is inferred where the child contracts for his services. and collects and uses his own earnings. (Scott v. White, 71 Ill. 287; 20 R. C. L. 610; 29 Cyc. 1675.) When a minor enlists in the military service of this country he ceases to be a part of his father's family and puts himself under the control of the government and is consequently emancipated so long as this service continues. (21 Am. & Eng. Ency. of Law,—2d ed.—1060; Commonwealth v. Morris, 1 Phila. 381; Baker v. Baker, 41 Vt. 55; Gapen v. Gapen, 41 W. Va. 422.) Enlistment is a contract between the soldier and the government which involves a change in his status which cannot be thrown off by him at his will. (In re Grimley, 137 U. S. 147.) Emancipation works a severance of the filial relation as completely as if the child were of age. Whether there has been an emancipation is a question of fact but what is emancipation is a question of law. The facts in this case are undisputed, and whether or not the deceased, in view of the undisputed facts in this record, was under legal liability to support his son who had enlisted in the military service is a question of law which the court must determine. Reginald Olesen was born July 21, 1898, and therefore would arrive at his majority before his term of enlistment expired. The emancipation of this son was brought about by the voluntary act of the parent and the child, and we think, both on authority and principle, it

must be held that deceased was not under legal obligation to support his son at the time of the injury in question.

The judgment of the circuit court is therefore reversed and the cause is remanded to the circuit court of Cook county, with directions to remand the cause to the Industrial Commission with directions to confirm the finding of the arbitrator. Reversed and remanded, with directions.

(No. 13341.-Judgment affirmed.)

HENRY SCHOELLKOPF et al. Appellees, vs. THE CITY OF
CHICAGO et al. Appellants.

Opinion filed June 16, 1920-Rehearing denied October 8, 1920.

1. RES JUDICATA—when confirmation of a special assessment is not res judicata of bill to enjoin performance of contract. A judgment confirming a special assessment for paving a street is not res judicata of a bill filed by the owners of the assessed property to enjoin the performance of the paving contract on the ground that specifications, added after the assessment was confirmed, call for a material wholly controlled by one manufacturer.

2. PATENTS-what does not constitute infringement of a patent. A patent on a certain wood-preserving oil containing not less than five per cent of tar acid is not infringed upon by producing oil containing the same per cent of tar acid through mixing the coal tar from which the oil is distilled with other coal tar having a higher percentage of acid.

3. SPECIAL ASSESSMENTS-municipality must not be victim of monopoly in endeavor to secure best material for improvement. It is important that a municipality obtain the best material and secure the best and most enduring improvement, but under the statute it must not be the victim of monopoly in procuring the best results.

4. SAME specification which tends to restrict competition is unlawful. Under section 74 of the Local Improvement act all contracts for the making of a public improvement to be paid wholly or in part by special assessment or special tax must be let to the lowest responsible bidder, and any specification which tends to restrict such competition is unlawful.

5. SAME when specifications restrict competition-injunction. Advertising for bids for paving with creosoted wooden blocks upon specifications which require that the blocks be treated with a cer

tain kind of wood-preserving oil which is produced by only one manufacturer restricts competitive bidding, and the city may be enjoined from performing a contract for paving with such material. CARTER and THOMPSON, JJ., dissenting.

APPEAL from the First Branch Appellate Court for the First District;-heard in that court on appeal from the Circuit Court of Cook county; the Hon. OSCAR E. Heard, Judge, presiding.

SAMUEL A. ETTELSON, Corporation Counsel, and GEORGE A. CURRAN, (CHESTER E. Cleveland, George P. Foster, LEON HORNSTEIN, and OTTO W. ULRICH, of counsel,) for appellants.

GEORGE A. MASON, and WM. T. HAPEMAN, (Dwight B. CHEEVER, and HENRY E. MASON, of counsel,) for appellees.

Mr. CHIEF JUSTICE CARTWRIGHT delivered the opinion. of the court:

The city council of the city of Chicago passed an ordinance on February 5, 1917, for paving the roadway of Sherman street with creosoted wooden blocks from the south line of Jackson street to the north line of West Van Buren street, and on March 12, 1917, the city filed its petition for the levy of a special assessment to pay the cost of the improvement. A judgment confirming the assessment was entered on May 21, 1917, and thereafter the city advertised for bids upon specifications as to the work and the preserving oil to be used, and providing that bidders should furnish an affidavit of the individual or the managing officer of a corporation or active member of a firm manufacturing creosoted blocks, setting forth that the oil used for treating the blocks was a distillate obtained wholly and entirely by distilling coal tar and free from any adulteration. Only two bids were received,—one from the Ryan Company and the other from John A. McGarry & Co.,—each stating that it

proposed to use the paving blocks manufactured and treated by the Republic Creosoting Company of Indianapolis, Indiana. The Ryan Company was the low bidder and the contract was entered into with the specifications attached, and the contractor being about to commence work, the appellees, owners of property assessed to pay for the improvement, filed their bill in the circuit court of Cook county charging that the city had added to the provisions of the ordinance, by the specifications for the work upon which bids were called for, conditions not contained in the ordinance, by specifying an oil which was a patented article owned or controlled by the Republic Creosoting Company, and that that company was the only distiller of coal tar that could supply the oil required by the specifications and controlled the supply of the same. The bill was answered with denials of the validity of the patent owned or controlled by the Republic Company, that the oil specified was a patented article owned or controlled by that company or that the specifications tended to restrict free competition in the bidding. There was a hearing and the bill was dismissed for want of equity. An appeal from the decree was first prosecuted to this court, but the validity of the ordinance not being questioned and the assignments of error presenting no question giving jurisdiction to this court, the cause was transferred to the Appellate Court for the First District. (Schoellkopf v. City of Chicago, 285 Ill. 458.) The Appellate Court reversed the decree and remanded the cause, with directions to order an injunction as prayed for in the bill, and gave a certificate of importance and allowed an appeal to this court.

It was insisted at the hearing that the questions raised by the bill were res judicata by the confirmation of the assessment for the improvement; and that would be true if the ordinance had contained the specifications alleged to have been restrictive of competition so that the question was or might have been at issue in that proceeding. The speci

fications in question, however, were not contained in the ordinance either in form or substance, but were included in the specifications at the instance or upon the advice of Peter C. Reilly, the patentee in the patent referred to and president of the Republic Creosoting Company, and no question was or could have been raised concerning them on the application for the confirmation of the assessment. The judgment confirming the special assessment determined nothing as to the added specifications.

The ordinance provided that the wood-preserving oil should be a distillate obtained wholly from coal tar containing not more than a certain per cent of insoluble matter and have certain specific gravity and other similar requirements. In calling for bids the city added to the specifications the following requirements not contained in the ordinance:

"6. The tar acids of the distillate from two hundred and fifty (250) degrees centigrade to three hundred and fifteen (315) degrees centigrade must not be less than five (5) per cent of this distillate (250 to 315 C.)

"7. The amount of the unsaponifiable oil (by sulphuric acid and caustic soda) in the distillate from two hundred and fifty (250) degrees centigrade to three hundred and fifteen (315) degrees centigrade must not exceed three and one-half (32) per cent of this distillate."

The controlling question of fact at the hearing was whether or not these added specifications limited or precluded competitive bidding, either because the requirement of not less than five per cent of tar acids called for a distillate which would be an infringement of the Reilly patent, or, if not an infringement of the patent, whether the production of such an oil was controlled by the Republic Creosoting Company and could not be obtained generally in the market by contractors desiring to bid for the work, and at the hearing all the evidence related to those questions, only.