My opinion is, that the master has drawn the time conclusions from the facts, which are stated in his report; and I have not the slightest hesitation in adopting them as the basis of my own opinion. The objections, which have been taken at the argument to the present patent granted to the plaintiff by the act of congress of 6th day of February, 1839, c. 14 [6 Stat. 748], I shall now proceed to dispose of, in as few words as may be practicable. In the first place, as to the point, whether, the plaintiff has sufficiently expressed in his specification the true nature, character and extent of the invention, which he claims. I am of opinion that he has.
Formerly, in England, courts of law were disposed to indulge in a very close and strict construction of the specifications, accompanying patents, and expressing the nature and extent of the invention. This construction seems to have been adopted upon the notion, that patent rights were in the nature *650of monopolies, and, therefore, were to be narrowly watched, and construed with a rigid adherence to their terms, as being in derogation of the general rights of the community. At present a far more liberal and expanded view of the subject is taken. Patents for inventions are now treated as a just reward to ingenious men, and as highly beneficial to the public, not only by holding out suitable encouragements to genius and talents and enterprise; but as ultimately securing to the whc#e community great advantages from the free communication of secrets, and processes, and machinery, which may be most important to all the great interests of society, to agriculture, to commerce and to manufactures, as well as to the cause of science and art.
In America this liberal view of the subject has always been taken; and, indeed, it is a natural, if not a necessary result, from the very language and intent of the power given to congress by the constitution [1 Stat. 14] on this subject. “Congress (says the constitution) shall have power to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right of their respective writings and discoveries.” Patents, then, are clearly entitled to a liberal construction, since they are not granted as restrictions upon the rights of the community, but are granted “to promote science and useful arts.”
Looking at the present specification, and construing all its terms together, I am clearly of opinion, that it is not a patent claimed for a function, but it is claimed for the machine specially described in the specification; that is, not for a mere function, but for a function as embodied in a particular machine, whose mode of operation and general structure are pointed out. In the close of his si>eeification the patentee explicitly states, that his “invention is described and expláin-ed in the second article of his specification, to which reference is made for information of that which constitutes the principle or character of his machine or invention, and distinguishes it, as he verily believes, from all other machines, discoveries, or inventions, known or used before.” Now, when we turn to the second article, we find there described, not a mere function, but a machine of a particular structure, whose modes of operation are pointed out, to accomplish a particular purpose, function, or end. This seems to me sufficiently expressive to define and ascertain what his invention is. It is a particular machine, constituted in the way pointed out, for the accomplishment of a particular end or object. The patent is for a machine, and not for a principle or function detached from machinery.
Then it is objected, that the description of the mode of constructing the machine is so defective, that it is not practicable for persons skilled in the art or science to which it belongs or relates, to construct the machine. This objection is put an end to by the master’s report, and the facts there stated by intelligent witnesses.
Then, it is suggested, that the grant of the patent by the act of congress of 1839, c. 14 [6 Stat. 748], is not constitutional; for it operates retrospectively to give a patent for an invention, which, though made by the pat-entee, was in public use and enjoyed by the community at the time of the passage of the act. But this objection is fairly put at rest by the decision of the supreme court in the case of the patent of Oliver Evans. Evans v. Eaton, 3 Wheat. [16 U. S.] 454.* For myself, I never have entertained any doubt of the constitutional authority of congress to make such a grant. The power is general, to grant to inventors; and it rests in the sound discretion of congress to say, when and for what length of time and under what circumstances the patent for an invention shall be granted. There is no restriction, which limits the power of congress to enact, where the invention has not been known or used by the public. All that is required is, that the patentee should be the inventor.2
The only remaining objection is, that the act is unconstitutional, because it makes the use of a machine constructed and used between the time of the passage of the act of 1834, c. 213 [6 Stat. 589], and the grant of the patent under the act of 1839, c. 14, unlawful, although it has been formerly decided, that under act of 1834 the plaintiff had no valid patent; and so the defendant, if he constructed and used thfe machine during that period, did lawful acts, and cannot now be retrospectively made a wrong-doer. If this were the true result of the language of the act it might require a good deal of consideration. But I do not understand, that the act gives the patentee any damages for the construction or use of the machine, except after the grant of the patent under the act of 1S39, c. 14. If the language of the act were ambiguous, the court would give it this construction, so that it might not be deemed to create torts retrospectively, or to make men liable for damages for acts, lawful at the time when they were done. The act of congress passed in general terms ought to be so construed, if it may, as to be deemed a just exercise of constitutional authority. And not only so; but it ought to be construed not to operate retrospectively, or ex post facto, unless that construction is unavoidable; for even if a retrospective act is, or may be constitutional, I think I may say, that according to the theory of our jurisprudence, that interpretation is never adopted without absolute necessity; and coruts of justice always lean to a more benign construction. But, in the present case, there is no claim for any damages, but such as have accrued to the patentee from a use of his *651machine since the grant of the patent under the act of 1839, c. 14.
[NOTE. For other cases involving this patent, see note at end of Blanchard v. Reeves, Case No. 1,515, and note at end of Blanchard’s Gun-Stock Turning Factory v. Warner, Id. 1,521.1I am, therefore, of opinion that there ought to be judgment for the plaintiff for the damages, agreed by the parties. Judgment accordingly.
See, also, Evans v. Eaton, 7 Wheat. [20 U. S.] 356; Evans v. Hettich, 7 Wheat. [20 U. S.) 453.