Crosby, J.

On March 15, 1920, the plaintiff entered into a contract with the defendant by the terms of which he agreed to work for the term of one year from date as superintendent of the defendant’s die casting department at a salary of $75 a week, payable weekly, and a bonus of $75 for each die casting die made during that period. The plaintiff worked under that contract until August 4, 1920, when the parties entered into another contract in writing, the essential parts of which are as follows:

" 1. The parties to this agreement have alreadyentered into a contract of employment of the said party of the first part, by the party of the second part, dated March 15,1920, which contract is hereby confirmed.

*482“2. In the course of his employment, the party of the first part agrees to use his best endeavor to invent and perfect a new die-casting machine for making aluminum heels.

“3. If the party of the first part is successful in perfecting a die-casting machine as aforesaid, the party of the second part agrees to accept same, and use it in the manufacture of its entire product of aluminum heels.

“4. The party of the second part agrees to pay as a royalty for his invention, provided same is successful, one-quarter of one cent royalty for each pair of aluminum heels manufactured by the party of the second part during the period of five years from the date of this agreement, subject to conditions stated in paragraph five of this agreement.

“5. It is further agreed that whenever the royalty aforesaid does not equal seventy-five (75) dollars per week, the salary of the party of the first part, as provided in contract of March 15, 1920, no royalty shall be paid, but that whenever the royalty exceeds seventy-five (75) dollars per week, then said royalty shall be paid instead of the weekly salary of seventy-five (75) dollars as aforesaid; it being understood that the royalty is to be paid in lieu of salary, whenever it exceeds the agreed weekly salary of seventy-five (75) dollars.”

The plaintiff was paid in full for his services to March 15, 1921, the period covered by the original contract. The controversy arises out of the provisions of the second contract. The plaintiff contends that he produced a machine which, in accordance with the contract, the defendant was bound to accept and use, and that it should account to him for the royalties accruing to him under the contract, and pay him $75 a week for every week in which they were less than $75, during the “period of five years from . . . August 4, 1920.” It is the contention of the defendant that the plaintiff failed to invent and perfect the machine as called for by the contract, and therefore the company is not hable in this action for damages for alleged breach of the contract. The case was referred to an auditor who found in accordance with the contention of the defendant. Afterwards, at the trial in the Superior Court, the jury returned a verdict in favor of the plaintiff. The defendant excepted to the refusal of the *483trial judge to direct a verdict in its favor, to Ms refusal to give certain requests for rulings, and to parts of the charge. The judge reported the case to this court. It was agreed that if the plaintiff was not entitled to recover any damages accruing after the date of the writ, the verdict, if for the plaintiff, should be limited to $1.

The evidence showed that the work done by the plaintiff in the construction of the machine was performed in the defendant’s factory with materials furnished by the defendant; that the machine was completed about October 1, 1920. The authority of the officers of the corporation to make the contract is not raised. The evidence submitted to the jury, besides the auditor’s report, consisted of the testimony of several witnesses. It was conflicting, the principal question in dispute being whether the plaintiff had performed his contract “to invent and perfect a new die casting machine for mating aluminum heels.” The issue presented was one of fact and we cannot say that as matter of law the conclusion reached by thé jury in favor of the plaintiff was unwarranted.

There was evidence which justified a finding that the defendant agreed to furmsh all the materials necessary for the construction of the machine. Philip Finberg, an officer of the defendant, testified that he “did not have anytMng to do with Mr. Sermuks’ work on the machine only to supply him and help him get the different things necessary; that Sermuks asked the witness from time to time for the different things wMch he said he needed in connection with the work,” and that they were furnished. There was other testimony from which it could be found that the defendant agreed to furmsh such materials. David Finberg, who was the defendant’s president in 1920 and 1921, testified that the company had spent between $10,000 and $12,000 in materials for the machine. The judge instructed the jury in substance that, if they believed “the testimony of the plaintiff and of the witnesses, named Finberg,” they would be warranted in finding there was an agreement, express or implied, between the parties that the defendant should furmsh the *484plaintiff the materials and means reasonably necessary to make the machine. These instructions were correct.

It could have been found from the conduct of the parties that an independent collateral agreement was entered into by which the defendant was to furnish all the materials required to construct the machine. It could have been further found that the plaintiff repeatedly requested the defendant’s officers to furnish him with a proper pyrometer for use on the machine; that the one furnished was old, inaccurate and valueless; that the defendant’s officers told him they would buy him a new one but that they failed to do so; that an air compressor which takes air into the machine and pumps it to the supply tank was furnished to the plaintiff by the defendant; that its greatest capacity was one hundred and twenty pounds to the square inch; that the plaintiff told the defendant’s officers this air compressor was inadequate, to obtain good results he needed one that would produce from two hundred and fifty to three hundred pounds pressure; that they furnished him another, not new, and with a maximum capacity of one hundred and eighty pounds; that he told them he could do nothing with it and requested one of three hundred pounds pressure, which they refused to furnish. There was evidence from which the jury were warranted in finding that if a proper pyrometer and air compressor had been furnished by the defendant the machine would have been in all respects in compliance with the contract.

It could have been found that the written agreement did not represent the entire contract between the parties; that in addition there was an oral agreement by which the defendant was to furnish the materials necessary for use in the construction of the machine. See v. Norris, 234 Mass. 345. See. v. Downey, ante, 47. The agreement so made was' one which the parties were authorized to make. This is not a case where oral evidence was admitted to vary, control or contradict a contract free from ambiguity. There is nothing in Waldstein v. Dooskin, 220 Mass. 232, contrary to what is here decided.

*485There was evidence tending to show that the plaintiff was successful in inventing and perfecting a new machine which complied in all respects with the written agreement, and that it would have produced suitable and perfect aluminum heels if the defendant had furnished a proper and sufficient pyrometer and air compressor to operate it as requested by the plaintiff. There was evidence that in certain respects it was a new machine and different from any that had been patented. At the trial counsel for the defendant, stated that the' defendant raised no question as to infringement. The jury could have found that after the machine had been built in conformity to the contract, the defendant refused to use it or to pay the plaintiff a royalty.

It is plain that the evidence warranted a finding that the defendant repudiated its contract. The breach went to the essence of the contract and entitled the plaintiff to sue for damages. He was not required to wait until the end of the term during which the agreement was to run, but could bring his action at once and recover full damages; and he is not limited in such recovery to damages accruing before the date of the writ. Speirs v. Union Drop Forge Co. 180 Mass. 87, 91. R. H. White Co. v. Jerome H. Remick & Co. 198 Mass. 41, 47. Randall v. Peerless Motor Car Co. 212 Mass. 352, 379-381, and cases cited. Burnham v. Dowd, 217 Mass. 351, 360. Garfield & Proctor Coal Co. v. New York, New Haven & Hartford Railroad, 248 Mass. 502, 507. Vitagraph, Inc. v. Park Theatre Co. of Boston, 249 Mass. 25, 31.

It is contended by the defendant that an action of this kind cannot be maintained in this Commonwealth unless there has been a breach before the date of the writ, and that to permit the jury to consider in determining damages the royalties that would have accrued is contrary to the Massachusetts rule respecting anticipatory breach. “It is often thought to allow a plaintiff to sue and recover full damages before the time for the completion of all the defendant’s performance is to allow the doctrine of anticipatory breach, yet this is not the case. As soon as a party to a contract breaks any promise he has made, he is liable to an action. In such an action the plaintiff will recover whatever damages *486the breach has caused.” Williston on Sales (2d ed.), § 585-a. Speirs v. Union Drop Forge Co., supra. St. John v. St. John, 223 Mass. 137. Barry v. New York Holding & Construction Co. 226 Mass. 14, 18, 19. Vitagraph, Inc. v. Park Theatre Co. of Boston, supra. Williston on Contracts, § 1292. Sedg. Damages, § 90. The doctrine enunciated in Daniels v. Newton, 114 Mass. 530, Deane v. Caldwell, 127 Mass. 242, and other cases cited by the defendant have no application to the facts in the case at bar. It follows that the defendant’s nineteenth request was rightly denied.

The defendant’s motion for a directed verdict and his first request were rightly denied. The judge repeatedly told the jury in substance and effect that, unless the plaintiff proved by a fair preponderance of the evidence that he had invented and perfected a new die casting machine which was successful and efficient in the quality and quantity of the product made by it, the plaintiff could not recover. There was no error in refusing to give requests two and three, as the evidence warranted a finding that the original contract had been modified by an oral agreement under which the defendant was to furnish the materials necessary for the construction of the machine. As the original agreement was silent concerning who was to furnish the materials, evidence of the oral agreement was admissible, not to contradict or vary the writing, but to explain and apply it and to show the meaning put by the parties upon the words they used. Willett v. Smith, 214 Mass. 494, 497. Gardner v. Denison, 217 Mass. 492, 495.

Requests five, six, seven, eight, nine, ten, eleven, twelve, fifteen, and seventeen were rightly refused: they related to questions of fact to be determined by the jury upon the evidence. Request thirteen could not properly have been given, for, if the defendant promised to furnish a proper air compressor, the consideration for which the plaintiff agreed to build the machine was a sufficient consideration for such promise. The sixteenth and eighteenth requests were rightly denied as the jury could have found that the defendant was., required to furnish a proper and suitable air compressor.

It is recited in the report that ‘ ‘ On the question of damages *487it was agreed by the parties at the trial that the amount of the royalties of one quarter of a cent on each pair of aluminum heels made by the defendant between March 21, 1921, the date of the writ in this action, and October 19,1922, when the defendant corporation ceased to do business, would be $3,125. . . . and that if the jury was not entitled to consider in determining damages the amount of royalties which would have accrued after the date of the writ, the verdict, if the plaintiff was entitled to recover, should be a nominal verdict of one dollar.” In view of this agreement, the jury in determining the damages were entitled to consider the amount of royalties which would have accrued after the date of the writ, and they were so instructed.

The exceptions to the charge are not argued and we treat them as waived. The jury returned a verdict for the plaintiff for $3,125 damages, with interest from the date of the writ.

No harmful error of law appears in the conduct of the trial: in accordance with the terms of the report the entry must be

Judgment for the plaintiff on the verdict.