We will now proceed to treat of some. of the detaila of our present law on this subject.
5. Of the subjecknatter of a patent The' act of July 4, 1836, provides' for the granting of a patent to the first inventor or diseeverer, Of any new and useful art, machine, raanu-' facture, or composition of 'natter, or of any new and useful improvement • thereon, The distinction between a process and'a machine is discussed in. 15 How, 252. There are with us, according to the phraseology of the sta tute, four classes of inventions which 'may be the subjects of patents: first, an art; second, a machine; third, a Manufacture; and, fourth,' a composition of 'natter. In Great' Britain, as We have seen, . letters patent granting exclusive privileges can be issued only to the inventors of a " new manufacture." But the courts, in defining the meaning of the term, have construed the word' " manufacture" to be coextensive in signification with the whole of the four classes of inteeritions thus re cognized by our law. An art or process, a machine, and a composition of matter are a!I regarded there as noanufactures. The field of invention in Great Britain is, there fore; cnincident with that provided by our law, and the legal subject-matter of patents is the same in each country. 2 Barnew. 8a Ald. 349 ; 8 Term, 99 : 2 H. Blackst. 492' 2 Mees. & W. Exch. 544; Webster, Pat. Cas. 237, 393, 459.
6. But, inasmuch as we have three other classes of inventions, the term " manufac ture" has a more limited aignification here than it receives in Great Britain. In this country it is understood to mean a new article of merchandise which has required the exercise of something more than ordinary mechanical skill and ingenuity in its con trivance: no new principle or combination of parts is necessary to render a patent of this kind valid. All that is requisite is that a substantially new oommodity shall have been produced for the public use and con venience. A mere change in the form of a well-known article may sometimes justify the granting of a patent for the same, where such change adapts it to an essentially new use, and where something beyond the range of ordinary skill and ingenuity must have been called into exercise in its contrivance. See 11 How. 248.
The general rule, then, is that wherever invention has been exercised there will be found the subject-matter of a patent. 1 Mc
All. C. C. 48. And as the law looks to the fact, and not to the result by which it was accomplished, it is inimaterial what amount of thought was involved in making the in vention. 4 Mas. C. C. 6.
I. Although the word "discoveir" is used in our statute as entitling the discoverer to a patent, still, every discovery is not a patent able invention. The discovery of a mere philosophical principle, or abstract theory, or elementary truth of science, cannot obtain a patent for the same, unless he applies it to some directly useful purpose. The patent can only be for such a principle, theory., or truth reduced to practice and embodied in a particular structure or combination of parts. 1 Stor. C. C. 285 ; 1 Mas. C. C. 187; 4 id. 1; 1 Pet. C. C. 342. Nor can there be a patent for a function or for an effect only, but for an effect produced in a given manner or by a peculiar operation. 1 Gall. C. C. 480 ; 1 Mas. C. C. 476 ; 1 Stor. C. C. 270 ; 2 id. 164; 1 Pet. C. C. 394 ; 5 McLean, C. C. 76 ; .15 How. 62.
An invention, to be patentable, must not only be new, but must also be useful. But by this it is not meant that it must be more use ful than any thing of the kind previously known, but that it is capable of use for a beneficial purpose. The word " useful" is also to be understood in contradistinction to "prnicious." or "frivolous." A contrivance directly a,nd mainly calculated to aid the counterfeiter, the.piokpocket, or the assassin, or which would in any way be directly cal culated to be injurious to the morals, the health, or the good order of society, would not be patentable. Neither would a new con trivance which was of too trivial a character to be worthy of serious consideration. 1 Mas. C. C. 186, 303 ; 4 Wash- C. C. 9 ; 1 Paine, C. C. 203 ; 1 Blatchf. C. C. 372, 488 ; 2 id. 132 ; 1 Woodb. & M. C. C. 290 ; 2 Lean, C. C. 35 : 5 Ill. 44 ; 1 Baldw. C. C. 303 ; 13 N. 11. 311 ; 14 Pick. Mass. 217 ; 16 Vt. 226. But it has been said that a court cannot pronounce a patent worthless, merely frorn the specification, without et idence of any experiments. 1 N. H. 347. In the trial of an action for infringement, evidence of the comparative utility of the plaintifra machine and the ilefendant's is inadmissible, except for the purpose of showing a substantial differ ence between the two machines. 1 Stor. C. C. 336.