in the manufacture; for he might thereby secure a longer monopoly than the fourteen years allowed by statute. So, too, if he commercially use the invention as a trade secret before he applies for a patent the same result would follow.1 Prior secret commercial (as distinguished from experimental) user of the invention by the inventor himself has been considered a ground for holding a patent to be invalid. But an inventor may keep the invention secret but unused for a long period before he applies for his patent without invalidating it.2

Illustrations.

A new process of manufacturing an old product was invented. The inventor sold considerable quantities of the product made by his new but undisclosed method. He subsequently took out a patent for the process. The patent was invalid. Wood v. Zimmer,3 Holt, N. P. 58. Manufacture by the patentee and his servants, without publication, of a patented article made by the patented method, for the purpose of having a large stock on hand ready for sale when the patent is obtained, is not prior user. Betts v. Menzies, 28 L. J. Q. B. 365. Racquets were made in November, 1883, for sale, but not sold nor exhibited till May, 1884. The patent was dated the 1st of January, 1884. It was a valid patent. Moss v. Malings, 3 R. P. C. 378.

Utility.

Another question connected with sufficiency of directions in the specification is that of " Utility." This condition of utility is not imposed in so many words by the Statute of Monopolies, but rests on it and other grounds. A patent may be held void for want of utility on the grounds of—

I. Public policy. This is implied by the statute.

II. False suggestion to the Crown.

III. Insufficiency of invention, i.e. the invention as made and described being useless for the purpose described.

The first ground rests on the common law. As the object of the

1 Betts v. Menzies (Lord Campbell), 28 L. J. Q. B. 365.

2 Bentley v. Fleming, 1 C. & K. 588.

This case was decided on two grounds, that here mentioned and insufficiency (ante, p. 74) Each ground may be regarded as the basis of the decision and the other a dictum, according as the necessity of the argument requires. Hence the point has recently been regarded as an open one. See Miller's Patent, 15 R. P. C. 213; see also Webster on Subject Matter (1841),

monopoly is to benefit trade and the industries of the country,' it will not be granted for an invention that is useless. Were this not the rule an inventor of a useless method or process might exact royalties from the users of subsequent inventions which, although coming within his patent, owe their utility and success to some subsequent improvement invented by another; 2 or might, on the other hand, prevent such useful improvements from being made. In such a case the earlier monopoly would come within the terms of the 6th section of the Statute of Monopolies (ante, p. 1), as being "mischievous to the State . . . or generally inconvenient." 3

As to the second ground, if the invention be represented as useful when it is of no use at all, the patent will be invalid because of the false representation made to the Crown; but in the absence of such false suggestion the uselessness of only a part of the invention claimed is no objection."

There are some dicta to the effect that utility must include some useful advance on what was known to the trade, i.e. that an invention fails for want of utility unless it is in some way more useful than that which is already known." But the majority of dicta are to the contrary effect."

8

Neither comparative nor commercial utility is to be taken as the test of validity.

Illustrations.

See Lewis v. Marling, ante, p. 76, as to an unnecessary part.

For an example of small utility see Neilson's Patent, post, pp. 187, 190. An electric glow-lamp was patented. Some were made, and lasted for

a considerable time. Very soon improvements were made in the mode of manufacture by which the lamps were "standardized"

1 Case of Monopolies, Noy, 182; Edgebury v. Stephens, 1 Webs. 35; 1 Hawk Pl. Cr. Ch. 79, sect. 20; R. v. Wheeler, 2 B. & Ald. 349.

2 Morgan v. Seaward (per Parke, B.), 2 M. & W. 562; 1 Webs. 197; Crossley v. Potter, Mac. 240 (per Pollock, C.B. 245); Walton v. Bateman, 1 Webs. 623.

The rule is put on this ground by Alderson, B., in Morgan v. Seaward, 1 Webs. 197. Bac. Abr. Prer. F. 2 (7th ed. vol. vi. p. 514), and notes to R. v. Mussary; Gordon on Monopolies, p. 268.

5 Morgan v. Seaward, 1 Webs. 197; Lewis v. Marling, 1 Webs. 495, 7.

• Cornish v. Keene, 1 Webs. 506; Losh v. Hague, 1 Webs. 203, 204; Young v. Rosenthal, 1 R. P. C. 29.

1 Lewis v. Marling, 1 Webs. 497; Morgan v. Seaward, 1 Webs. 172; Otto v. Linford, 46 L. T. 41; Plimpton v. Malcomson, 3 Ch. D. 582; Tetley v. Easton, Mac. P. C. 63; Philpott v. Hanbury, 2 R. P. C. 37; Pirrie v. York Street Flax Co., 10 R. P. C. 39.

Fawcett v. Homan, 13 R. P. C. 411.

• Badische Anilin u. Soda Fabrik v. Levinstein, post, pp. 312, 314.

G

and otherwise improved. None were sold on a commercial scale except those made with the improvements. Held, there was utility at the date of the patent, which was therefore valid. Edison &Swan v. Holland, 6 R. P. C. 277, 283 (post, p. 319), 285.

A patent was obtained for producing dyes from certain substances. Out of a series of colours the dye for one colour only had a sale. The other dyes were not therefore useless. Badische Anilin, &c. v. Levinstein, post, p. 311.

The third ground for the rule is the most important in practice. If the invention be not fully developed so as to obtain the result intended by the patentee, then the invention is entirely useless for that purpose when made as described, and the patent will be invalid. Much more so if the invention be useless for every purpose; or if, in addition to its failure to accomplish the intended purpose, it be dangerous to the public.

There is no case reported of a patent being held invalid for the want of utility alone in an invention that produced the result, or accomplished the object, described by the patentee. Patents that have been held invalid for want of utility were either also invalid on other grounds, or failed to work as described, or were impracticable 1 or "useless for the avowed purpose."

Utility as a test for, or as evidence of, ingenuity or novelty has been dealt with, ante, pp. 38, 39.

Illustrations.

An invention consisted in an alleged improvement in the construction of fowling-pieces and small arms. It consisted of a hole so perforated as to let the air and not the powder pass out from the barrel to the pan. The specification contained the following passage:-"Now the intention of this improvement in perforating the hammer, grooving or hollowing out the seat, is to let the air out of the barrel and pan; in putting down the wadding the powder in the barrel, by the air being allowed to pass, is forced into the perforated receiver A, so that the touch-hole is always full of powder, and by these means firearms of all kinds are prevented from flashing or hanging fire." So far from preventing "hanging fire," the gun, with this improvement, would not fire at all; but by enlarging the hole, so as to allow powder out as well as air, it would work well. Held that the patent was invalid because the utility of the

1 United Horsenail Co. v. Stewart, 2 R. P. C. г32.

2 United Horsenail Co. v. Swedish Horsenail Co., 6 R. P. C. 8.

invention and purpose of the patent wholly failed. Manton v. Parker, Dav. P. C. 327. [This is the first case (1814) of want of utility since the Statute of Monopolies.]

A process, in which heating was necessary and was not so stated, was held a useless invention. Simpson v. Holliday, post, p. 244. An invention consisted of a system for signalling on railways. The ultimate object was to secure the safety of the travelling public. According to the specification this was secured, “it being impossible to set the points and signals antagonistic to each other." It was proved, however, that it was quite possible for signalmen using the system to turn several trains on one line without difficulty. The patent was invalid for want of utility. Easterbrook v. G. W. Ry. Co., 2 R. P. C. 207. In a system of distribution of electricity Planté cells were used for the purpose of automatically keeping the pressure in the mains at a certain amount. Owing to the cells discharging at a potential difference less than that required to charge them, this effect, as intended by the patentee, could not be produced. But the cells were useful when a switch was used to add extra cells to compensate for the change in the potential difference of the cells. The patent was invalid. Lane Fox v. Kensington, &c., post, p. 345. The last case and the first (Manton v. Parker) are very similar. Neither invention would work when made as described and claimed, but a slight alteration made each workable and useful. Cases of patents being held invalid for want of utility alone are very rare.

Utility, as essential to validity, is therefore utility for the purpose indicated by the patentee. Want of utility to defeat a patent must be want of utility in the invention as claimed, and not that of auxiliary or alternative things mentioned in the specification. The existence of utility does not depend on whether the invention is practically used in the form in which it is specified, or is superseded by improvements. It may exist in cases where, owing to commercial reasons, the manufacture cannot be successfully worked.5 As with other grounds for invalidating a patent, if the claim to one monopoly fail for want of utility, the whole patent fails."

This case is also an illustration of a patent being invalid as being, in the words of the Statute, " generally inconvenient," i.e. dangerous to the public.

2 Lane Fox v. Kensington (per Lindley, L.J.), post, p. 350.

Cornish v. Keene, 1 Webs. 506.

Edison v. Holland, 6 R. P. C. 277, 283, 285.

Badische Anilin, &c. v. Levinstein, 4 R. P. C. 462, 466.

• United Horsenail Co. v. Swedish Horsenail Co., 6 R. P. C. 8, following Templeton v. Macfarlane, 1 H. L. Ca. 595. As to subsidiary claims, see ante, pp. 58, 63; Lewis v. Marling, ante, p. 76.

CHAPTER VI.

CONSTRUCTION OF SPECIFICATIONS.

General Principles-Proportions, p. 88-Claims, p. 89-Benevolent Construction, p. 93-Doctrine of Equivalents, p. 96—Amended Specifi

cations, P. 99.

General Principles.

IF a patent be granted, members of the public (who are interested, as provided in sect. 26 of the Act of 1883, post, p. 494) or the law officers may present a petition for revocation on grounds on which formerly a patent might be repealed by scire facias.

When a patentee sues in an action for infringement of his patent, the defendant may plead that the patent is invalid on the same The validity of a patent is therefore, in the majority of grounds. tested when a petition for revocation is presented or an action brought for infringement.

cases,

Hence, logically, in an action for infringement, the extent of the monopoly claimed should be ascertained before the alleged infringement is considered.1

Again, with regard to novelty, a question frequently arises as to whether the claim includes what has been published before. As it is quite possible for a patentee, through ignorance, to claim what is old, the meaning and extent of his claim should be ascertained without regard to the allegation of anticipation. The importance of a correct construction or interpretation of the specification is therefore manifest, for on the extent of the claim the validity of the patent very often depends, and also, on the other hand, the question whether a certain manufacture be an infringement or not. As earlier specifications and other publications have to be looked to as part of the

1 See Seed v. Higgins (as explained in Potter v. Parr), post, p. 216.

: Per Blackburn, J., in Betts v. Menzies, 31 L. J. Q. B. 237, and post, p. 219.