In Cheetham v. Nuthall (i), it was provided that the licence should determine if the patent was declared invalid; in an action · brought by the licensor against a third party for infringement, the patent was held to be invalid, but this judgment was reversed by consent; the defendant after due notice continued to work under his licence, and it was held that he was still liable to pay royalties for the use of the invention.

An assignee of a share of the profits is entitled to an account of the profit from the person by whom they are payable; but the account should be taken once for all in the presence of all the persons interested (j).

Sect. 23 of the Act provides :-" (1) There shall be kept at the Patent Office a book called the Register of Patents, wherein shall be entered the names and addresses of grantees of patents, notifications of assignments and of transmissions of patents, of licences under patents and of amendments, extensions and revocations of patents, and such other matters affecting the validity or proprietorship of patents as may from time to time be prescribed; (2) the register of patents shall be primâ facie evidence of any matters by this Act directed or authorized to be inserted therein; (3) copies of deeds, licences and any other documents affecting the proprietorship in any letters patent or in any licence thereunder, must be supplied to the comptroller in the prescribed manner for filing in the Patent Office."

By sect. 85, "There shall not be entered in any register kept under this Act, or be receivable by the comptroller, any notice of any trust, express, implied, or constructive." Sect. 87, as amended by sect. 21 of the Patents, &c., Act, 1888, provides for the entry in the register, at the request of the person becoming entitled, of any assignment or transmission of interest. The person registered shall have power to deal with such interest as he has registered, absolutely: "Provided that any equities in respect of such patent, &c., may be enforced in like manner, as in respect of any other personal property." Sect. 88, as amended by sect. 22 of the Patents, &c., Act, 1888, deals with the inspection of registers, and the

(i) 10 P. O. R. 321.

(j) Bergmann v. Macmillan, L. R.,

17 Ch. D. 423.

obtaining of certified copies. By sect. 89 sealed copies are to be received in evidence.

The effect of these sections is to prohibit the entry upon the register of simple notices of trusts, but any other documents affecting the proprietorship of the patent, whether by creating trusts or otherwise, are not to be excluded (); it has been already noticed that an assignment of a patent should be by deed, but an agreement to assign is an equitable assignment, and consequently may be entered on the register under section 23 (1), but the documents containing the agreement and entered on the register must be complete, and upon which specific performance of the agreement could be enforced, since otherwise no legal or equitable interest in the patent or proprietorship thereof would pass (m).

Sect. 90, as amended by sect. 23 of the Patents, &c., Act, 1888, empowers the Court (High Court of Justice) to order the alteration of the registers, upon the application of persons aggrieved, and upon sufficient cause shown. The comptroller may himself correct errors in registers which are merely of a clerical nature, sect. 91.

The comptroller may refuse to enter upon the register of patents a document dated before the patent, upon the ground that it does not contain a sufficient proof of title (n).

The regulations affecting registration under the above sections are contained in Patents Rules, 1890, rules 67-79.

Sect. 35 of the Act of 1852, after providing for the registration of proprietors, assignments, &c., of patents, proceeded: "Provided always, that, until such entries shall have been made, the grantee or grantees of letters patent shall be deemed and taken to be the sole and exclusive proprietor or proprietors of such letters patent, and of all licences and privileges thereby given or granted."

It will be observed that the Act of 1883, quoted above,

(k) Stewart v. Casey, 9 P. O. R. 9, 11, 15.

(7) Ibid., at p. 15; see also In re Fletcher's Patent, 10 P. O. R. 252. (m) In

re Fletcher's Patent, 10

P. O. R. 252, 255; Haslett v. Hutchinson, 8 P. O. R. 457, 466.

(n) In re Parnell's Patent, 5 P. O. R.

126.

materially differs from this enactment. Hence Chollett v. Hoffman (o), and Hassall v. Wright (p), will not now apply.

Prior to the Act of 1883, the High Court of Justice exercised jurisdiction to alter and amend the register of patents (9).

The register should be amended whenever a fraudulent entry has been made. A patentee assigned half a patent to A., and afterwards he assigned the whole to B. by deed, reciting that he had already granted a licence to work and use to A. B.'s assignment was first registered :-Held, that B. had constructive notice of A.'s rights, and an entry was ordered to be made in the register that the licence referred to in B.'s assignment was the deed of assignment to A. subsequently entered (r).

Registration does not amount to notice to the whole world, so where the grant of an exclusive licence for a district had been entered on the register, it was held that this did not amount to notice so as to affect an innocent purchaser outside of that district bringing his purchase within the district in violation of the rights of the licensee (s).

A co-owner of a patent has no right to cause an entry to be made in the register, which purports to affect or prejudice the rights of the other, and should he do so, the entry will be expunged at the instance of the injured party (†).

(0) 7 Ell. & B. 686.

(p) L. R., 10 Eq. 509; 40 L. J., Ch. 145.

(q) In re Morgan's Patent, 24 W. R.

245.

(r) In re Mosey's Patent, 25 Beav.

581.

(s) Heap v. Hartley, 5 P. O. R. 603; 6 P. O. R. 495.

(t) In re Horsley & Knighton's Patent, L. R., 8 Eq. 475.

CHAPTER XIII.

ESTOPPEL.

HAVING assigned a patent, the original patentee cannot manufacture the patented article; should he do so and an action for infringement be brought against him by his assignee, he may not set up the defence that the patent is invalid; he is estopped by his deed (a), that is, by the deed of assignment, but when the assignment is by operation of law there is no such estoppel. In Cropper v. Smith (b), in 1873, letters patent for improvements in lace machines were granted to H., who in 1877 went into liquidation and the patent was sold by the trustee to the plaintiffs. H. afterwards entered into partnership with S., and this action was brought against S. and H. to restrain them from infringing the patent; held that H. was not estopped from disputing the validity of the patent either by matter of record, on the ground that the letters patent were of record; or by deed, by reason of the specification being under his seal; or by matter in pais, on the ground of the statements in his petition to the Crown, there being nothing to show that the plaintiffs bought on the faith of those statements. (But see Bankruptcy Act, 1883, sect. 50, sub-sect. 5.) It is probable that there is estoppel by record between the Crown and the grantee of letters patent (c), but this would only be against the subject, since no estoppel operates against the Crown. In an action brought by the assignor to enforce an agreement for an assignment of letters patent, it is

(a) Oldham v. Langmead, cit. in Hayne v. Maltby, 3 T. R. 438; Lainson v. Tremere, 1 A. & E. 792; Chambers v. Crichley, 33 Beav. 374.

(b) L. R., 26 Ch. D. 700; L. R., 10

App. Cas. 249; 1 P. O. R. 81; 2 P.
O. R. 17.

(c) Per Fry, L.J., L. R., 26 Ch. D at p. 712.

not open to the assignee to challenge the validity of the patent (d).

An assignment of patent rights in a partnership dissolution. deed will estop the retiring partner from subsequently setting up the invalidity of the patent by way of defence to an action brought by his late partners (e). But where the plaintiff and defendant had been partners, and had worked as such the defendant's patent, there being no deed between the plaintiff and defendant which inferred the validity of the patent, held that plaintiff was not estopped from denying the validity of the patent (f). And where partners are joined as defendants in an action for infringement, and one is assignor of the patent, the other is not debarred from setting up the pleas of invalidity (g).

In Bowman v. Taylor and others (h) the plaintiff sued the defendants for the non-payment of certain royalties due from the defendants to the plaintiff under a licence under seal for the use of the plaintiff's patent. The defendants defended on the grounds (1) that the invention was not a new invention, (2) that the plaintiff was not the first and true inventor, (3) that the specification was not sufficient-pleas which in effect endeavoured to put in issue the validity of the plaintiff's title. Upon demurrer, Taunton, J., said, "The law of estoppel is not so unjust or absurd as it has been too much the custom to represent. The principle is, that where a man has entered into a solemn engagement by deed under his hand and seal as to certain facts, he shall not be permitted to deny any matter which he has so asserted. The question here is, whether there is a matter so asserted by the defendant under his hand and seal that he shall not be permitted to deny it in pleading. It is said that the allegation in the deed is made by way of recital, but I do not see that a statement such as this is the less positive because it is introduced by a 'whereas.' Then the defendant has pleaded

(d) Smith v. Buckingham, 21 L. T. 819; 18 W. R. 314; Liardet v. Hammond Electric Light Co., 31 W. R. 710; Hall v. Conder, 26 L. J., C. P., 138; 3 Jur. N. S. 366; 2 C. B., N. S. 22.

(e) Chambers v. Crichley, 33 Beav.

374.

(f) Axmann v. Lund, L. R., 18 Eq. 330; 22 W. R. 789.

(g) Heugh v. Chamberlain, 25 W. R. 742.

(h) 2 A. & E. 278.