We do not think the testimony of the witness Bice, as to the alleged agreement, not expressed in the writing — “that, at the time of the execution of said mortgage, it was understood and agreed between plaintiffs and defendant, that said advances or supplies were to be furnished or delivered by the plaintiffs to the defendant as they were the preceding year” — offended the rule, that oral testimony will not be received to vary the terms of a written contract. We hold, that this contract, which is continuous in its character, belongs to a class which, on their face, indicate, that they do not express all the details to be observed in their performance. The writing is silent as to the times when, and quantities in which, the supplies were agreed to be furnished. In such case, if there was an agreement which supplied this omission, though not in the writing, such agreement may be proved. This is one of the exceptions to the rule which forbids that oral proof shall be received to add to, or vary, the terms of a written contract. To furnish supplies, is a very general term; and to cast on the court or jury its interpretation, without furnishing to them any guides therein, is necessarily to expose the question to uncertain and varying solution. Hence, any agreement, or conversation of the parties, shedding any light on this question, may be proved ; and such proof does not vary any term of the contract, either in its letter or spirit. — Self v. Herrington, 11 Ala. 489 ; Mobile Dock v. McMillan, 31 Ala. 711; Drake v. Goree, 22 Ala. 409; McLendon v. Godfrey, 3 Ala. 181; Brown v. Isbell, 11 Ala. 1009; Corbin v. Sistrunk, 19 Ala. 203; 1 Greenl. Ev. §§ 286, 288, 292, 294, 295, 295a ; Garrow v. Carpenter, 1 Porter, 359 ; Wayland v. Mosely, 5 Ala. 430.
2. If there be no positive agreement, fixing and defining the manner in which contracts, such as the one we are now considering, shall be performed, then the parties are presumed to contract in reference to the usage in the particular trade or employment, if there be such usage. — 1 Greenl. Ev. § 292. But a custom or usage, to become obligatory, must be shown to be so general and uniform, as to raise the presumption that the parties knew of it, and contracted in reference to it. — Desha, Smith & Co. v. Holland, 12 Ala. 513 ; McClure v. Cox, Brainard & Co., 32 Ala. 617; Barlow v. Lambert, 28 Ala. 704; Ala. & Tenn. Rivers Railroad Co. v. *424Kidd, 35 Ala. 209. The proof of usage in this case was, we think, wholly insufficient; and that part of the testimony should not have been received. — Steele v. McTyer, 31 Ala. 676; Ala. & Tenn. R. R. Co. v. Kidd, supra.
3. The cotton in controversy was grown during the year 1874, on a plantation then in the possession of defendant, Rice. Only one witness testified as to the terms of the contract, by which Rice employed his laborers, whose labor cultivated the crop ; and he testified, also, as to the interest of the laborers in the cotton in controversy. His testimony is as follows : “ That he made a contract with his laborers, at the commencement of the year 1874, by which he agreed to give them one-fourth of cotton produced on said plantation during said year, and to feed them, as a compensation for their services in making said crop; * * * that five bales of said cotton were left by him at his gin-house, with the understanding with his laborers, who, under his contract with them, were to receive one-fourth of the same, until he could have a settlement with them; that all of said laborers claimed one-fourth interest in said cotton under said contract.” The other bale of said cotton had been previously given off by said Rice to a laborer employed under another contract, as part of his wages. The mortgage, under which plaintiffs claimed, was dated January 24th, 1874; and it was given to secure advances afterwards to be made, and in part to secure a debt for advances made the year preceding. This mortgage was filed in the probate office for record February 13th, 1874. Among other property, it conveyed “alll my crop of corn, cotton, peas, potatoes, hay, &c., to be raised by me and my hands on my said farm, or on all -other lands that I may cultivate the present year, with all my right, title, and interest in said property, warranted free from incumbrance, and against any adverse claim-”
In Smyth v. Tankersly, 20 Ala. 212, speaking of a contract not distinguishable from this, this court said, the parties to the agreement were tenants in common of the products to be grown and divided between them. In the case of Thompson v. Mawhinney, 17 Ala. 362, a similar contract was adjudged to create a tenancy in common. To the same effect are Strother v. Butler, 17 Ala. 733 ; and Williams v. Nolen, 34 Ala. 167.
4. Among the postulates of the second charge given are, that the jury should find that Rice’s contract with the laborers was such as is stated in his testimony above, and that the contract was made before the mortgage to plaintiffs was recorded. These facts being found by the jury, it would necessarily result, on the principles above stated, that, but *425for the mortgage, Bice and the laborers were tenants in common of the cotton that remained undivided ; and the claim set up by plaintiffs being only the title of Bice conveyed by the mortgage (he could convey none other), it follows, that the plaintiffs became tenants in common, with the laborers, - of the cotton so grown.
5. To maintain the action of detinue, the plaintiff must have the right to the immediate possession. One tenant in common has no right to dispossess another; and neither can maintain detinue against the other; for neither has the right to exclusive possession. If one convert the entire property thus held, by destroying, consuming, or disposing of it, the other may maintain trover for his interest; but he can not maintain detinue. — Perminter v. Kelly, 18 Ala. 716, and authorities there cited; Williams v. Nolen, 34 Ala. 167.
We have referred above to the question submitted by the court in its charge to the jury, — whether Bice contracted with the laborers before the mortgage to the plaintiffs was recorded. The charge made that one of the conditions of the defendant’s defense. We recur to it, for the purpose of saying, that we do not, in this case, decide whether that inquiry was or was not material. We leave that question undecided. To answer it properly, would render it necessary to construe the mortgage, and ascertain whether it conveys any portion of the crop, other than that which properly belonged to Bice ; and might also raise the question of laborers’ lien. Upon these inquiries we propose not to enter, as they are unnecessary in this case.
If the supposed facts in the second charge given were found by the jury to be the true facts, then the plaintiffs could not recover the cotton sued for; not because they would show any right in Bice, or that plaintiffs had no interest in the cotton; but because they disprove entire and exclusive right in the plaintiffs to immediate possession, which is indispensable to the maintenance of the action of detinue. There was, therefore, no error in the second charge given.
What we have said above conclusively shows, that the Circuit Court did not err in the charge given, numbered one, nor in the refusal to give the charge asked.
6. We have said above, that the Circuit Court erred in allowing testimony of the witness Bice as to usage. When error is shown, injury will be presumed, unless the presumption is repelled, by showing affirmatively that it could not possibly have exerted any injury. — 1 Brick. Dig. 780, § 100. But, if it be clearly shown that no injury resulted from the erroneous ruling, or that a losing plaintiff, who complains of the error, cannot recover in the action, then such error fur*426nishes no ground for a reversal. — 1 Brick. Digest, 780, §§ 96, 97, 98; Boswell v. Carlisle, at this term. In the present record, all the testimony is set out. Tenancy in common was the question of merit, on which the charges were based, and on which the verdict was found. The usage attempted to be proved did not bear, in the least, on this question. It did not, and could not, enter into the defense on which the case went off. We hold, that the error in this case could not possibly have worked any injury to the appellants.
The judgment is affirmed.