Mr. Justice Breese

delivered the opinion of the Court:

There is but one point of any importance to be considered, arising on this record. That is the first and second instructions given by the court for the defendants in error, They are as follows: “In the absence of a special agreement, the defendants are chargeable for no more than the just value of the use of the premises over the amount of the labor performed by them upon the premises, if such labor was done by the consent and with the knowledge of the plaintiff or his agent.” “ If the use of the premises was worth no more than the labor so performed by defendants, with the assent of the plaintiff or his agent, the jury should find for the defendants.”

We do not understand the law to be as declared in these instructions. Though mutual demands may be set off, and damages growing out of the same transaction may be recouped, they can only be set off or recouped where demands legally exist. The defendants had no legal demand against the plaintiff, for the excavations of clay made upon his land. They were not employed or requested to make them, and though made with the knowledge and consent of the plaintiff, he could not be made their debtor thereby.

A person may own a tract of land heavily timbered, which he may be desirous of having cut down and removed. Should a party, without any authority of the owner, yet with his knowledge, go upon the land, fell the timber and remove it for his own purposes, it could not be said, in an action brought by the owner for the value of the timber, that here were mutual demands, one of which must be set off against the other, and that the true measure of damages, what is the timber worth over and above the expense of cutting and removing it. The true criterion, we think, is, what was the .timber worth to him who appropriated it ? So if one owns a large manure heap, and another, with the knowledge of the owner, but without any agreement, removes it, and sells it or otherwise appropriates, the question is not the difference in value between removing the manure and the manure in pile, but what- was it worth to him who appropriated? So with this clay, though it might have been a benefit to the plaintiff to have it excavated and removed out of the way, the inquiry is, what was this clay worth to the defendants who appropriated it to their own gain and profit ?

There was error in refusing to give the plaintiff’s first instruction, and in giving the defendants’ first and second instructions, for the one is the converse of the others. For these errors the judgment is reversed and the cause remanded.

Judgment reversed.