As with other questions of fact, damages must be proved with at least reasonable certainty. They cannot be ascertained by mere speculation and conjecture.1 Accordingly, if there are no data for computing the amount of damages no substantial damages can be given even if it is clear from the evidence that some damage has been sustained.2 So where defective goods were sold by a wholesaler to a retailer, injury to the retailer's trade is too uncertain to form a basis of recovering damages.3 As between two or more possible rules for the measure of damages the law prefers the most certain. Thus on breach of a contract to give a free pass for life, the measure of damages has been held to be the amount actually spent on railroad fare.4 This rule often prevents recovery of profits contemplated by the injured party. Thus on breach of a contract to make a lease of certain realty to be used as a peach orchard, which breach consisted in evicting plaintiff within two years after he had taken possession; and after he.had planted the peach trees, it was held that future profits could not be recovered, but that the measure of damages was the value of the plaintiff's interest in the orchard at the time of eviction.5 On breach of a contract of employment, the employe to be paid by commissions, he may in case of wrongful discharge recover compensation for his time and expenses ;6 or his reasonable expenses in advertising and commissions on orders actually secured by him before his discharge.7 So under a contract whereby A is to make certain tests of his patent and B is to manufacture and sell such invention, A may recover for the expenses of the tests and the value of his time where B sells out his business before performing the contract.8 However, if a certain minimum amount of damages is shown, that, at least, may be recovered, though the evidence may show that the damages were greater than such amount by some uncertain sum.9

1 Jemmison v. Gray, 29 la. 537; Paxton v. Vadbouker, 1 Neb. (Unofficial) 776; 96 N. W. 378; Douglass v/Ry., 51 W. Va. 523; 41 S. E. 911.

2 Louisville Bridge Co. v. Ry., - Ky. - ; 75 S. W. 285.

3 Jackson Sleigh Co. v. Holmes, 129 Mich. 370; 88 N. W. 895.

4 Curry v. Ry., 61 Kan. 541; 60 Pae. 325.

5 Rhodes v. Baird, 16 O. S. 573. 6Cadman v. Markle, 76 Mich.

448; 5 L. R. A. 707; 43 N. W. 315.

7 Taylor Mfg. Co. v. Hatcher, 39 Fed. 440; 3 L. R. A. 587.