Mr. Presiding Justice Holdom delivered the opinion of the court.
2. Sales, § 15* — when not void for want of mutuality. A contract by which a seller of batteries agrees to furnish sufficient of the contract commodity to meet the requirements of the purchaser for a 12-month period, and the purchaser agrees to devote its best efforts in promoting the sale of the batteries, is not void for want of mutuality. 3. Contracts, § 181* — how intention of parties to unambiguous contract determined. Where a contract is not ambiguous, the intention of the parties cannot be determined by evidence aliunde, but by the language employed in the contract itself. 4. Contracts, § 177* — what is legal inquiry in construing. In construing a written contract the legal inquiry is as to what was the intention of the parties. 5. Sales, § 64*- — how contract for sale of batteries and for promotion of resale construed. A contract for the sale of batteries, under which the seller agrees to furnish a sufficient number to meet the purchaser’s requirements for a year and the purchaser agrees to buy them and devote its best efforts in promoting the sale of the batteries, must be construed as providing that the seller was to furnish the buyer with batteries as described in it to meet all the buyer’s requirements for a year, as those requirements might materialize during that time with the buyer devoting its best efforts to promote the sale of the batteries. 6. Sales, § 19* — validity of verbal order for goods. A verbal order for goods is just as binding as a written one, when proven. 7. Evidence, § 221* — what is not hearsay. In an action by a buyer against a seller to recover damages for breach of contract in failing to supply plaintiff with the requisite number of batteries to fill its orders, plaintiff’s evidence as to such orders was not hearsay. 8. Sales, § 376* — when discounts are elements of damages for breach of contract. In an action by a buyer against a seller to recover damages for breach of contract in failing to supply plaintiff with the requisite number of batteries to fill its orders, the discounts allowed by the contract were properly proven as elements of damages. 9. Contracts, § 13* — when claim of want of mutuality is untenable. Where a party partly performs a contract he cannot afterwards, at his own election, avoid its further performance upon the alleged ground of want of mutuality.