#### Rudolph S. Blome and William J. Sinek, Trading as Rudolph S. Blome Co., Defendants in Error, v. Illinois Portland Cement Paving Company, Plaintiff in Error.

Gen. No. 17,217.

1. Estoppel — necessity of encouraging prejudicial acts. Though persons licensed to lay pavement containing an invention covered by letters patent wrote letters to the licensors which stated the amount of pavement laid under the terms of the contract, they were not thereby estopped, in an action for sums due under the *172contract, from showing that the letters were written under a misapprehension as to what the terms of the contract covered and that the material laid was not the substance covered therein, as there was no misrepresentation of fact which either induced or encouraged the licensors to act differently than they otherwise would have acted.

2. Contracts' — construction. Under a contract which licensed persons to lay pavement containing an invention covered by letters patent, requiring the making of reports to the licensors of the laying of any pavement containing the invention, the paying therefor of a certain sum per square yard, and reserving to the licensors the right to contract to lay pavements and to license others, the licensee is not required to use the patent of the licensor in all the pavement constructed, but merely to do the things agreed on in case it does so use the material.

Error to the Municipal Court of Chicago; the Hon. Stephen A. Poster, Judge, presiding. Heard in the Branch Appellate Court at the March term, 1911.

Reversed and remanded.

Opinion filed October 1, 1912.

S. E. Lambert, for plaintiff in error.

Perley H. Bishop, for defendants in error.

Mr. Presiding Justice Clark

delivered the opinion of the court.

In December, 1908, the defendants in error, hereinafter called the plaintiffs, issued a license to the plaintiff in error, hereinafter called the defendant, to lay pavements in the City of Chicago, “embodying and containing the invention of said letters patent,” the letters patent being described as No. 855,105. In the contract granting the license it was provided that the defendant should make full and true reports in writing to the plaintiff, under oath if required, within thirty days after the completion of the laying by it of any pavements “containing the invention of said letters patent,” and to pay within thirty days after the completion of the work twenty-five cents per square yard. The plaintiffs reserved to themselves the right to enter into any public or private contracts for the *173laying of pavements, and also the privilege of licensing any other person, firm or corporation to lay pavements in the City of Chicago by public contract. The plaintiffs further agreed to use their best efforts to secure any permits from the City of Chicago that the defendant might desire.

The record shows that in July, 1909, a statement of the indebtedness admitted to be due to the plaintiffs was made by the defendant, detailing the number of yards of pavement said to have been laid and to be subject to the terms of the contract, and a remittance was made for the amount at twelve and one-half cents per square yard. The change from twenty-five cents to twelve and one-half cents per square yard is apparently not explained. In December, 1909, a similar statement was made showing, as expressed, “a total yardage of 6,661% square yards.”

There was a trial before the court without a jury, and a finding for a portion of the amount claimed, and a judgment entered thereon.

It is insisted by the'defendant, first, that the pat-" ent No. 855,105 was not issued to the plaintiffs and did not cover improvements in pavements and methods of making the same. There was,' however, introduced in evidence patent No. 856,105 and it is evident that the court rendered the finding upon the assumption that the latter patent was the one intended to have been referred to in the contract and the one the parties had in mind when the contract was entered into. At the .trial the defendant attempted to show that the letters written, which included a statement'of the amount of pavement admitted therein to have been laid under the terms of the contract, were written under misapprehension; that the defendant did not know at the time it entered into the contract what was covered by patent No. 855,105 or by No. 856,105; that after writing the letters it discovered that the pavement which it had been laying was not *174covered by tbe letters patent, bnt was of a very different mixture and very different construction. Tbe court'held that it was estopped by the letters it had written from making this defense. In this we think the court erred. There was no misrepresentation by the defendant, and there is nothing which it did which either induced or encouraged the plaintiffs to act differently than they otherwise would have acted. Weaver v. Peasley & Co., 163 Ill. 251.

Defendant was not required by the contract to use the patent of the plaintiffs in all the paving which it constructed. The contract merely provides that when pavement was laid by the defendant of the kind protected by the plaintiffs’ patent (wrongly described) it should pay the amount specified. We think the evidence with reference to the matter should have been received. The judgment will be reversed and the cause remanded.

Reversed and remanded.