mercy of those whose profit is derived from selling rights or granting licenses to others; and as each owner may fix from its use, see Fraser v. Gates (1885), 118 Ill. 99; Gates v. Fraser (1881), 9 Bradwell (Ill.), 624. That a surviving partner who uses a patent belonging to the late firm, against the objection of the representative of the deceased partner, is liable to account to such representative for one half the profits resulting from such use, see Freeman v. Freeman (1886), 142 Mass. 98. That a part owner may be accountable to his co-owners for a share of the profits obtained by him from using the invention or selling rights, see Aspinwall Mfg. Co. v. Gill (1887), 40 O. G. 1133; 32 Fed. Rep. 697. That whether one co-owner can compel another to account for one half the license fees, etc., received by him is doubtful, see Gates v. Fraser (1881), 9 Bradwell (Ill.), 624. no principle, in the absence of contract, which can prevent any persons not prohibited by statute from using any invention whatever. Is there any implied contract where two or more persons jointly obtain letters-patent, that no one of them shall use the invention without the consent of the others, or, if he does, that he shall use it for their joint benefit? I can discover no principle for such a doctrine. It would enable one of two patentees either to prevent the use of the invention altogether, or else to compel the other patentee to risk his skill and capital in the use of the invention on the terms of being accountable for half the profit, if profit should be made, without being able to call on his co-patentee for contribution if there should be loss.' Now while this is the principle announced by the Chancellor, it perhaps should be with this qualification, that if one of the patentees obtains more than his share of the profits, he might be held liable under certain circumstances to the others. Certainly I do not wish to be understood as affirming that there is never such liability. Of course we must take into consideration any risk which he may run, any outlay of money which he may make in the manufacture or sale of the article; but if, looking at it upon equitable principles, he has obtained more than his share of the profits arising from the thing patented, either in the use or sale of it, or of licenses, it seems to me he might in certain cases be held accountable to the That where one of several joint-patother joint patentees." 2 Bann. & A. entees assigns to a third party, the 327 (328). estoppel against him operates as a See also Clum v. Brewer (1855), 2 license to the third party, and the Curtis, 506. That each co-owner of a patent may use the right without the concurrence of the others and license at will, see Washburn & Moen Mfg. Co. v. Chicago Galvanized Wire Fence Co. (1884), 109 Ill. 71. That a license by one co-owner is good against all, and their remedy is by account against him, see De Witt v. Elmira Nobles Mfg. Co. (1876), 66 N. Y. 459. That one joint-owner cannot compel another to account for a share of his profits from a sale of the patented articles, see Vose v. Singer (1862), 4 Allen, 226. other patentees must look to the assignor for an account, see Curran v. Burdsall (1883), 27 O. G. 1319; 20 Fed. Rep. 835. That one co-owner cannot be obliged to account to the other for the mere use of the invention or for profits arising his own price on the rights or licenses he grants, his liability to account to his co-owners for their share affords them no security of proper compensation. This rule seems to have been reached by treating property in a patented invention as analogous to property in a personal chattel, and endeavoring to apply to one the principles which govern the ownership of the other. If the sole property in a patented invention consisted in the right to practise it, some remote analogy to property in a personal chattel might exist. But the actual value of the property in a patented invention resides in the monopoly, by virtue of which its owners can not only prevent the use of a single personal chattel but of all others which are substantially identical with it in character. The right to practise the invention cannot be conferred without affecting these prohibitory powers, and no rule which ignores them, and permits the transfer of the invention without reference to its effect on them, can meet the requirements of the case. The second rule is far more just, and more in accordance with the nature of the subject, and in closer analogy to the rules applied to the joint-ownership of certain incorporeal rights to which those of the co-owners of a patented invention bear the nearest but by no means a perfect resemblance. It restricts the power of alienation on the part of a joint-owner within such limits as prevents an increase in the burden placed upon the common property of all, permitting him to enjoy his interest himself or to convey it to another single owner, whether an individual, a co-partnership, or a corporation, but not allowing him to multiply the number of those who are relieved from the monopoly without the consent of his co-owners. This rule also has its hardship, since it compels the joint-owner to practise the invention, or to sell his interest to a single purchaser or to such a group of purchasers as are acceptable to his co-owners, or to remain without the enjoyment of his property; but it is a rule conservative, not destructive, of the value of the patented invention as a whole, and entails on him no greater disadvantage than now rests upon the joint proprietors of a common, or a wharfing privilege, or any other incorporeal right, an increase in the number of whose occupants is forbidden by the law unless it be with the express or implied permission of all the existing owners.2 §797. Joint-Owners cannot Practise Infringing Inventions. Although the courts have recognized the right of one jointowner to multiply indefinitely the number of those who can lawfully practise the patented invention without reference to 2 Although no exact similitude exists between a patent privilege and any other property, yet the resemblance which it bears to a common of pasture is sufficient to suggest a possible solution of the present question. Both the patent privilege and the common of pasture are to be exercised within definite territory by specified means of enjoyment, and with a limited and determinable amount of profit. In both, the appropriation to himself, by one owner, of more than his just share of such profit is an unjust invasion of the rights of the others, whether, in the one case, by the introduction of an excessive number of commonable beasts, or, in the other, by distributing the patent privilege to an increased number of proprie. tors or licensees. Any assignment of either right which does not impose a greater burden on the common property, and any use of either by the owner which does not curtail its proper use by his co-owners, is fair and equitable although the ultimate result to him may far exceed any advantage which his co-owners may actually at tain. Now the law finds no difficulty in regulating the rights and duties of commoners of pasture. It recognizes the fact that the profit is limited in amount and, therefore, prevents its distribution among a greater number of cattle than the owners have the right to introduce. But it does not measure the keenness of their appetites, nor the capacity of their stomachs, nor the benefit derived by one owner over another on account of his choicer breed of animals or the higher value to him of the food obtained. So far as analogy may be taken as a guide at all in such cases, does not this suggest that the joint-owners of a patent privilege enjoy all the rights to which they are entitled, as against each other, when each is allowed to practise the invention without accountability to his co-owners for any benefit which his superior skill or larger capital may enable him to realize, and to assign his interest to one other person, natural or artificial, for what price he pleases, with the same power to use and to assign; but that, as in the case of a commoner, he should not be allowed to introduce into the common property a greater number of those agencies by which its profits are to be absorbed, to the inevitable diminution of the advantage which his co-owners would otherwise have rightfully enjoyed? This suggestion, based on the nature of the property in the invention, takes no notice of the injury done to one owner of a patent by another when the latter prevents the former from exercising the prohibitory powers of the monopoly in his own defence, as under the present rules of law often occurs. But under this suggestion, that injury would also be avoided, since each owner could still enforce his rights against every person except the coowner or the single individual to whom his interests had been assigned. its effect on his co-owners, it has been held that neither a joint-owner nor his alienees can lawfully practise an infringing invention. This limitation may appear inconsistent with § 797. In Herring v. Gas Consumers' Association (1878), 3 McCrary, 206, Treat, J. (206) "The direct question presented is whether an infringer of a patent can escape liability for his infringement because he is a joint-owner of the original patent upon which the infringement occurs. The cases cited do not reach the precise point raised by the bill. It is evident that if a stranger was guilty of the infringement he would be compelled to respond in damages. Can a part-owner infringe the common patent and escape all liability? If he can, it is obvious that, however small his aliquot part, he can make the enjoyment of the patent valueless to his jointowner. He has, by virtue of the jointownership, a right to use the patent, but he has no right, more than a stranger, to infringe the same. If there is an infringement, the right of recovery is in the party wronged. All the joint-owners should ordinarily be parties plaintiff, but if the wrong-doer is one who is guilty to the damage of the other joint owner, the other should not be left remediless. As to such infringement they are strangers. All the joint-own ers are on the record, and the amount of the recovery determines their respect ive interests. The infringer cannot escape the consequences of his wrong to his joint-owner by averring that he was by his infringement injuring not his joint-owner alone, but himself also. In other words, he cannot, under cover of his interest in the common patent, shield every wrong-doer who may infringe that patent. He can, as to the other part owners, by infringing, become liable to them for the wrong done. The amount of recovery will be in pro portion to their respective interests. Were this not so, the door would be open to the grossest frauds by one jointowner against all other joint-owners. The case of Pitts v. Hall, 3 Blatchf. 204, and the comments thereon in Curtis, Pat. § 108 et seq., do not cover this case. The question there discussed pertains to the use by one joint-owner of the common property. The difficulties in maintaining an action for an infringement against a joint-owner who merely uses the common patent may be insurmountable. As to that no opinion is expressed. In this case an entirely new and distinct proposition is presented, viz.: one of the several joint-owners is not using the common patent, but an infringing patent. His defence is that inasmuch as he had a right to use the original patent without question from his joint-owners, under the decision in Pitts v. Hall, supra, he has a right also to use any infringing patents, on the ground that his right to use the original being vested in him, his use of other and infringing patents did not cause any wrong or injury to himself as joint-owner. In other words, the defendant contends that as one jointowner he could use the common patent without being liable to account to the other joint-owners; that he could not be sued as an infringer for using what he had a right to use by virtue of his proprietary interest; and, therefore, if he used an infringing device, he was only injuring himself in what he had a proprietary right to forbid. This would be correct if no interest except his own were involved, for a man may do what he pleases with his own, and “volenti non fit injuria” would be, a fortiori, applicable in such a case. If a stranger were using the infringing patent, this action would unquestionably lie against him; and the question before us is the latitude allowed him under the preceding rule, but it is sound in principle. The powers included in his ownership of the invention are only such as can be exercised within the scope of the patent, by making, using, or selling the invention therein described and claimed; and his ownership of the monopoly, which exists only for the protection of his interest in the invention, does not entitle him to perform acts which would be an infringement in a stranger, unless they are the precise acts involved in the practice of the patented invention. The use by him of an infringing art or instrument is neither the practice of the patented invention nor the employment of prohibitory powers in its defence. It is an act entirely outside of the enjoyment of his rights as the owner either of the invention or of the monopoly. Acts of the same character on the part of licensees are equally beyond the privileges conferred upon them by their license, and are not affected by the estoppel which prevents the enforcement of the monopoly against their practice of the patented invention.2 Joint-owners and their licensees are, therefore, as to such acts of infringement regarded as strangers to the patented invention, and are liable in damages to the other owners according to the proportion of their respective interests therein. §798. Reciprocal Relations of Joint-Owners Variable by Con tract: Their Relations to Third Parties. While these general rules govern the relations of jointowners in the absence of any special contract between them, whether it will lie against a joint-owner, or, in the language of the bill, whether he, under cover of his joint ownership, can infringe and escape liability. So far as he acts outside of his interests or rights or powers as a joint-owner, there is no adequate reason for treating him, quoad hoc, otherwise than as a stranger. If this be not so, then one joint-owner may destroy, without remedy, the rights of the other joint owners." 21 O. G. 203 (203); 3 Bann. & A. 253 (254); 9 Fed. Rep. 556 (556). That one joint-owner can enjoin an other in certain cases, see Duke v. Graham (1884), 19 Fed. Rep. 647. That one co-owner is not estopped from denying the validity of the patent as against the others, see Marston v. Swett (1875), 4 Hun, 153; 6 Thomp. & C. 534. 2 That a licensee is liable for infringement if he uses any other inven tion substantially identical with the one covered by his license, see Miller's Falls Co. v. Ives (1877), 14 O. G. 203; 14 Blatch. 169; 2 Bann. & A. 574. |