express terms upon the assignee a right to future improvements on the invention, it cannot affect an independent invention; nor can a general conveyance of the interest of the assignor in all his patents previously obtained create a title in the assignee to a subsequent improvement upon any one of the assigned inventions.2 The invention transferred by the assignment to the assignee also remains in him distinct from any other invention which he may acquire. The meeting in a single person of the ownership of several patented inventions does not unite the inventions, nor confer upon their owner any rights which could not have been asserted by the several owners of the different patents.3 Thus where the elements

of a combination are separately patented the assignee of all these patents does not become thereby the owner of the combination, nor can he use the elements combined without a license under the patent for the combination. Nor can the assignee of several patents lap one upon the other, and in this manner cover features of the invention which the patents in the hands of separate owners would not protect.

§ 778. Assignment Transfers only the Monopoly Created by

American Patents: Its Effect on Foreign Patents.

But while the operation of an assignment is thus uniformly limited to the invention covered by the patent, the scope of the monopoly conveyed is not invariable. An inventor may secure for his invention one monopoly under his original American patent, another dependent on the first under each re-issue, a third still dependent on the first, but more distinct from it than a re-issue, under an extension, and others under foreign patents. In connection with the invention, he may assign any one or several of these concurrent or successive monopolies, and which will pass under a given conveyance depends upon the terms of the assignment and the presumptions of law. That an assignment of the invention carries one of these monopolies is evident, since the possession of prohibitory powers is essential to the effective ownership of the entire interest or any undivided part of the entire interest in a patented invention. Hence an assignment before patent creates an equitable title in the assignee to the original term of the future American patent, and if in due form and properly recorded it vests in him the legal title also when the patent is actually granted. Re-issues, being dependent on and superseding the original patent, likewise pass by such assignment unless the assignee prefers to hold his monopoly as created by the original patent.1 An assignment during

rights than the respective patents conferred on their patentees; so that the assignee claiming under both could, by lapping one over the other, or incorporating parts of one into the other, obtain a right, unpatented, which neither of the assignors could separately maintain.

No such doctrine can be accepted. Each patent must rest on its own merits alone. Munson v. Gilbert & Barker Mfg. Co., 3 Bann. & A. 595." 16 Fed. Rep. 669 (671).

§ 778. That as far as an assignment of a patent is concerned, the re

the original term has the same effect on the monopoly arising from the original or re-issued patent, the legal title thereto always vesting in the assignee. The monopolies created by foreign patents, having no legal existence in the United States and being controlled entirely as to their operation and assignment by foreign laws, are not affected by any transfer of the patented invention, or of the invention before patent, which can be recognized and sustained in this country as the conveyance of a monopoly. For this reason an assignment of an invention, whether before or after the issue of an American patent, does not transfer the monopoly created by a foreign patent, nor does the existence of a foreign patent at the date of the assignment preclude the assignee from claiming title to the monopoly arising under the patent granted by the United States. An express provision in such assignment transferring foreign patents would at best be but a contract which equity could enforce against the assignor by compelling him to execute such instruments as, under the foreign law, would operate as a conveyance of the monopoly within the country for which it was granted.

§ 779. Effect of Assignment upon an Extension.

It being certain that in every case an assignment operates upon the original term of the American patent and upon its reissues, and that it never operates upon a foreign patent except by virtue of the laws of the country where the patent is in force, the only doubt which can arise in reference to the effect of an assignment upon the monopoly relates to an extension. An extension, when allowed by law, is intended for the benefit of the inventor.1 It is permitted to him only on the

ground that his inventive skill has not received a sufficient reward during the original term, and that this insufficiency is not due to his own fault or neglect. It was not provided as a recompense to the assignees for the devotion of their capital or their business energies to the development of the invention and the distribution of its practical results among the public.3 Thus an extension can be obtained by the inventor alone, if living, or by his administrator or executor after his death.* At the same time, the possibility of an extension adds to the value of the invention even before the original patent has been issued; and if he then is able to transfer it, and obtain a higher price on that account, he indirectly receives the recompense which the extension was intended to bestow. Hence the law recognizes his right to transfer this monopoly as well as any other, only requiring that, as a simple assignment of the invention is satisfied by the passage of the original term, an instrument which is to operate upon the extension must expressly and unequivocally include it. The presumption as to any given assignment is that it does not refer to the extension; and therefore, if its words can be construed to relate only to the original term and the re-issues, the assignment will be limited to these monopolies. Thus an assignment of all the assignor's right, title, and interest "during the term for which a patent may be granted;" or a conveyance of "all the patents which the grantor now has, or has in contemplation to obtain;" or a transfer of "all my right and title to the patent and the invention thereby secured;" or the assignment before patent of all the rights "I

benefit, see Ex parte Munger (1873), 3 O. G. 323; Ex parte Baker (1872), 1 O. G. 632.

See also § 836 and notes, post. 2 See Sec. 18, act of 1836.

That the extension of a patent does not enure to the benefit of an assignee of the original term, see Wilson v. Rousseau (1846), 4 How. 646; 2 Robb, 372.

5 See § 770 and cases cited, ante.

6 That the assignment of a patent during the original term, or before the patent issues, does not carry the extension unless there are express words to that effect, see Hendrie v. Sayles (1878), 98 U. S. 546; Gibson v. Cook (1850), 2 Blatch. 144; Case v. Redfield (1849), 4 McLean, 526; 2 Robb, 741; Phelps v. Comstock (1848), 4 McLean, 353; Brooks v. Bicknell (1845), 4 McLean, 64; Woodworth v. Sherman (1844), 3 Story, 171; 2 Robb, 257.

4 See Sec. 18, act of 1836; also Woodworth v. Wilson (1846), 4 How. 712; 2 Robb, 473; Woodworth v. Sherman (1844), 3 Story, 171; 2 Robb, 257.

now have, or by letters-patent should be entitled to have," to the invention "to the full extent to which the same could be enjoyed by me but for this assignment," and providing for the issue of the patent to the assignee "as the owner of the whole right and title" to the invention; or a conveyance of "the patent" or of the "invention " after the patent has been granted, — have all alike been held to operate upon the original term and the re-issues only, for want of words which necessarily included the extension. On the other hand it has been said that an assignment before patent of "the invention" without any restrictions, or an assignment of "the invention and of all rights that may from time to time be

That a conveyance, during the original term, of all right, title, and interest during "the term for which letters-patent are or may be granted" does not carry an extension, see Gear v. Grosvenor (1873), 3 O. G. 380; Holmes, 215; 6 Fisher, 314.

That an assignment of the "right, title, and interest" in letters-patent about to be issued does not carry an extension, see Johnson v. Wilcox & Gibbs Sewing Mach. Co. (1886), 23 Blatch. 531; 27 Fed. Rep. 689.

That the grant of all patents which the grantor now has or has in con. templation to obtain," does not carry an extension, see Wetherell v. Passaic Zinc Co. (1872), 2 O. G. 471; 6 Fisher, 50; 9 Phila. 385.

That an assignment by the patentee of all his right and title to the patent and to the invention thereby secured does not cover the extension, see Waterman v. Wallace (1875), 13 Blatch. 128; 2 Bann. & A. 126.

That an assignment, before a patent is granted, of all the right "I now have or by letters-patent would be entitled to have" in the invention, "to the full extent to which the same could be enjoyed by me but for this assignment," and providing for the issue of the patent to the assignee, "as the owner of the whole right and title"

to the invention, does not cover an extension, for want of words showing an intention to convey a future interest, see Mowry v. Grand St. & Newtown R. R. Co. (1872), 10 Blatch. 89; 5 Fisher, 586.

That an assignment of the "patent" does not carry the extension, see Ex parte Holmes (1873), 4 O. G. 581.

That the assignment of an "invention" after a patent issues is the grant only of the current term, see Waterman v. Wallace (1875), 13 Blatch. 128; 2 Bann. & A. 126.

That an assignment of the "invention" does not carry the extension, unless expressly so stated, see Ex parte Holmes (1873), 4 O. G. 581.

That the term for which letterspatent may be granted" in the habendum is to be construed by the rest of the deed, and usually includes nothing except re-issues, see Jenkins v. Nicholson Pavement Co. (1870), 4 Fisher, 201; 1 Abbott, 567.

That a contract by the patentee in 1829 that his assignee shall have the benefit of all renewals, covers only reissues, and not extensions, in the hands of the administrator, extensions being unknown to the law at the date of the contract, see Wilson v. Rousseau (1846), 4 How. 646; 2 Robb, 372.