29. Harmful inventions not patent- 43. Prior foreign patent.

able.

30. Art.

44. Unity or diversity of invention. 45. Division of the application.

17. WHAT MAY BE PATENTED.-Any person who has invented or discovered any new and useful art, machine, manufacture, or composition of matter, or any new and useful improvement thereof, not known or used by others in this country, and not patented or described in any printed publication in this or any foreign country before his invention or discovery thereof, and not in public use or on sale for more than two years prior to his application, unless the same is proved to have been abandoned, may, upon payment of the duty required by law and other due proceedings had, obtain a patent therefor. (Act of July 8, 1870, § 24.)

18. INVENTIONS FIRST PATENTED ABROAD MAY BE PATENTED IN THE UNITED STATES. -No person shall be debarred from receiving a patent for his invention or discovery, nor shall any patent be declared invalid by

reason of its having been first patented or caused to be patented in a foreign country, provided the same shall not have been introduced into public use in the United States for more than two years prior to the application, and that the patent shall expire at the same time with the foreign patent, or, if there be more than one, at the same time with the one having the shortest term; but in no case shall it be in force more than seventeen years. (Ib., § 25.)

19. AN ABSTRACT PRINCIPLE NOT PATENTABLE UNLESS REDUCED TO PRACTICE.-A discovery of some new principle, theory, or elementary truth, abstracted from its application, is not a new invention, and cannot be protected by a patent. To entitle himself to a patent the applicant must reduce it to practice, must embody it in some practical machine or method of rendering it available or useful. (Whitney v. Emmett, Bald., 311; Evans v. Eaton, Pet. C. C., 341, 342.)

And when the discovery is reduced to practice by any means, old or new, resulting usefully, it is patentable, independent of the machinery by which the application is made. (Foote v. Silsby, 2 Blatchf., 265.)

20. APPLICATION OF A LAW OF NATURE.-He who first discovers that a law of nature can be applied, and, having devised machinery to make it operative, introduces it in practical form to his fellow-men, is the inventor not merely of the mechanism, but of the force which operrates through the mechanical medium. He may assert and establish his property not only in the formal device for which mechanical ingenuity can at once, as soon as the principle is known, imagine a thousand substitutes, but in the essential principle which his machine was the first

to embody and announce to mankind. (Parker v. Hulme, 1 Fish., 44.)

Thus, where a patentee claimed the application of the expansive and contractive power of a metallic rod, by different degrees of heat, to open and close a damper which governs the admission of air into a stove, it was held, that it was a valid claim, not being for a principle, and that the patent was good. (Silsby v. Foote, 20 How.,

385.)

21. A PATENT CAN IN NO CASE be for an Effect only, but for an effect produced in a given manner or by a peculiar operation. No patent can be obtained for the admeasurement of time or the expansive operations of steam, but only for a new mode or new application of machinery to produce these effects; and therefore if new effects are produced by an old machine in its unaltered state, no patent can be legally supported, for it is a patent for an effect only. (Whittemore v. Cutter, 1 Gall., 480.)

The application of ether to surgical purposes was an effect produced by old agents, operating by old means upon old subjects. The effect alone was new, and was a mere discovery, which, however novel and important, is not patentable. (Morton v. New York Eye Infirmary, 2 Fish., 320.)

An end to be accomplished is not the subject of a patent; only the new and useful means to accomplish it. (Carver v. Hyde, 16 Pet., 519.)

But the discovery of the application of some property in nature never before known or in use, by which is produced a new and useful result, is the subject of a patent, independently of any peculiar or new arrangement of

machinery for the purpose of applying such new property. (Foote v. Silsby, 2 Blatchf., 264.)

And the inventor has the right to use any means, new or old, in the application of the new property to produce the new and useful result, to the exclusion of all other means. (Ib.)

Where a result is in a greatly improved manufacture, it may become the test of invention, and from which invention may be inferred. (Treadwell v. Fox, MS. Appeal

Cases, D. C., 1859.)

22. NEW APPLICATION; DOUBLE USE.-The application of an old thing to a new purpose is not patentable. The thing itself which is patented must be new, and not a mere application of it to a new purpose or object. (Bean v. Smallwood, 2 Story, 411.)

The inventor of a machine has made it for all the uses to which it is applicable, and no one can obtain a second patent for the machine by applying it to a new use. (Woodman v. Simpson, 3 Fish., 98.)

But a new adaptation and arrangement of applying and using old articles for a certain purpose-for example, using old parts of a caster adapted to furniture in a manner before unknown-may be the subject of letters patent. (Blake v. Sperry, 2 N. Y. Legal Obs., 251.)

And though a combination of machinery is not new in the abstract, yet it is patentable if used and applied in connection with the practical development of a newly discovered principle producing a new and useful result. (Tatham v. Le Roy, MS. N. Y., 1849.)

Where the principle of the alleged invention has been discovered and applied before, the new application will

be what is called a double use. (Blandy ex parte, MS. Appeal Cases, D. C., 1858.)

The application of a thing already known to a new and useful purpose may be the subject of a patent, provided the new use is not analogous to the old, and requires the exercise of inventive faculties. (Winans v. Schenectady and Troy Railroad, 2 Blatchf., 293.)

If the patentee was the first and original inventor of the application and use of plaster of Paris to the filling of fire-proof safes, and this application produced a new and useful result, it cannot be doubted that it is a proper subject of a patent. (Rich v. Lippincott, 2 Fish., 1.)

An invention or arrangement of parts, though already used for a particular purpose, is patentable, if in the new use it performs any new function, or an old function in a better manner, or makes a better or cheaper manufacture. (Newman ex parte, MS. Appeal Cases, D. C., 1859.)

The substitution of a jewel in place of glass in a sewing machine to prevent friction in the passage of the thread is not patentable; it is but the double use of an old contrivance, with no new effect or result. (Berry ex parte, MS. Appeal Cases, D. C., 1859.)

The making of an instrument of india rubber and silver, if a useful effect is secured thereby, may be the subject of a patent, though such article may have before been made entirely of metal and also entirely of rubber. Such an invention is not a double use. (Adams ex parte, MS. Appeal Cases, D. C., 1860.)

23. MECHANICAL EQUIVALENTS.-The substitution of a known mechanical equivalent is not an invention within the patent law. (Blanchard's Gun-Stock Turning Company v. Warner, 1 Blatchf., 278.)