is most nearly connected, to make, construct, compound, and use the same. And in case of any machine, he shall fully explain the principle, and the several modes in which he has contemplated the application of that principle or character, by which it may be distinguished from other inventions; "and shall particularly specify and point out the part, improvement or combination, which he claims as his own invention or discovery."

Sec. III.-KNOWN PROCESSES, METHODS AND MACHINERY NEED NOT BE DESCRIBED. SURPLUSAGE

Though the specification must be full, it need not describe in detail, processes, methods, and machinery, that are well known and in ordinary use among those skilled in the art, science, or business to which the invention relates, or with which it is most nearly connected. A specification of an improved gas apparatus did not give any directions respecting a condenser. It was held that this did not invalidate the patent, it being well known to persons capable of constructing a gas apparatus, that a condenser was an

3

3 Kneass v. Schuylkill Bank, C. C. U. S. Penn. Oct. 1820, Coxe's Dig. 532.

essential part of it. To introduce such descriptions. may not merely be superfluous; it may have the effect of rendering the specification defective by involving the description of the invention with a multitude of immaterial details, whereby it might be rendered obscure, and perplex those who should attempt to learn from it what the patentee claimed, that they might avoid an infringement, or who should resort to it after the expiration of the monopoly, to learn how to make the article.

Where superfluous details and erroneous statements are apparently introduced for the purpose of throwing obscurity upon the invention, and disguising it, and evidently having that tendency, the patent will thereby be rendered void, as we shall see more particularly below."

It may be necessary to give a partial description of a well known, or patented process or machine, in order to give a clear description of an improvement; any thing further than this will at best be immaterial and superfluous, if it does not vitiate the patent."

Crossley v. Beverly, 3 Car. & Payne, 513. See also The King v. Arkwright. Dav. Pat. Cas. 135; Hubbart v. Grimshaw, Dav. Pat. Cas. 297; Hill v. Thompson, 2 J. B. Moore, 450. 5 Sec. 5. Savory v. Price, 1 R. & M. 1.

• See below, Sec. 4, 2 H. Bl. 497.

Watt's specification was an instance where mere superfluity was held not to vitiate the patent; for in addition to the description of his steam-engine, he intimated new projects of invention, concerning which, Eyre C. J. said, "If there be a specification to be found in that paper which goes to the subject of the invention as described in the patent, I think the rest may well be rejected as superfluous."

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Sec. IV. THE SPECIFICATION IS ADDRESSED ΤΟ ARTISTS. TECHNICAL TERMS.

The patentee is allowed, in his specification, to address himself only to persons of competent skill in the matter to which the patent relates. It is not necessary, that the specification should contain an explanation level with the capacity of every person, which often would be impossible." Suppose," says Eyre C. J. "a new invented chemical process, and the specification should direct that some particular chemical substance should be poured upon gold in a

7 Boulton v. Bull, 2 H. Bl. 498.

8 Per. Abbott C. J. The King v. Wheeler, 2 Barnw. & Ald. 354; Per Lord Loughborough, Arkwright v. Nightingale, Dav. Pat. Cas. 56.

Per. Story, Lowell v. Lewis, 1 Mason, 182.

state of fusion, it would be necessary in order to this operation, that the gold should be put into a crucible, and should be melted in that crucible, but it would be hardly necessary to state, in the specification, the manner in which, or the utensils with which the operation of putting gold into a state of fusion was to be performed. They are mere incidents with which every man, acquainted with the subject, is familiar."'10 Mr. Justice Washington, speaking of the provisions of the act of Congress of 1793, relating to specifications, remarks, that the expressions are very strong, and seem intended to accommodate the description, which the patentee is required to give, to the comprehension of any practical mechanic, skilled in the art of which the machine is a branch, without taxing his genius or his inventive powers." The provisions of the act of 1836, s. 6, are substantially the same on this subject as those of the former statute.

As the specification is addressed to artists acquainted with the subject of the patent, it is no ground of objection that it contains technical terms. It would be quite impracticable to give a description of many inventions without the use of such terms, and the de

10 2 H. Bl. 497.

11 Gray & Osgood v. James, and others, 1 Pet. C. C. R. 376,

scription is often rendered much more clear by the use of them, even where others might, by circumlocution, be used instead of them. It was objected to a specification, in one case, that it contained French terms; but this was considered by Abbott C. J. to be no ground of objection.12

Sec. V.-THE SPECIFICATION MUST BE TRUE, AND

MUST NOT MISLEAD.

That the specification must be true in all its material parts, cannot be doubted, for the wrong statement of what is material, will render the specification de-fective, either as a notice of what the invention is, or as a direction for practising it. If the patent and specification state an invention which has not been made by the patentee, the patent is no doubt void. "If," says Abbott C. J. "the patentee has not invented the matter or thing of which he represents himself to be the inventor, the consideration of the royal grant fails, and the grant consequently becomes void. And this will not be the less true, if it should happen, that the patentee has invented some other matter or thing,

12 Bloxam v. Elsee, 1 Car. & P. 558.