patents, is of itself an offence, no matter at what time such improvement was devised or made, whether the word "devise," which has been a good deal criticised, is synonymous with make as one of the plaintiff's council seemed to think, or means to invent, a mere act of the mind, à construction, which whether it be to make or contrive, to plan, form or design, it is unnecessary in this case to decide, because the charge against the defendant is the using of the plaintiff's improvement unconnected with the making and devising it.

But it is objected to this construction, that it would render the law ex post facto in its operation, in respect to one who has erected his improvement prior to the granting of the patent of the plaintiff.

It must be confessed that cases of great hardship may occur, if after a man shall have gone to the expense of erecting a machine for which the inventor has not then, and never may obtain a patent, he shall be prevented from using it by the grant of a subsequent patent, and its relation back to the patentee's prior invention. But the law, in this case cannot be termed ex post facto, or even retrospective in its operation, because the general law declares before hand that the right to the

patent belongs to him who is the first inventor, even before the patent is granted; and therefore, any person, who, knowing that another is the first inventor, yet doubting whether that other will ever apply for a patent, proceeds to construct a machine, of which it may afterwards appear that he is not the first inventor, acts at his peril, and with full knowledge of the law, that by relation back to the first invention, a subsequent patent may cut him out of the machine thus erected.

Not only may individuals be injured by a liberal construction of the words in the law, but the public may suffer, if an obstinate or negligent inventor should decline obtaining a patent, and at the same time keep others at arm's length, so as to prevent them from profiting by the invention for a length of time; during which the fourteen years are not running on. But these hardships must rest with Congress to correct. It is beyond our power to apply a remedy. No such hardships exist in the present case, where the defendant erected the improvement with a knowledge not only that the plaintiff was the first inventor, but had absolutely obtained a patent, although it was afterwards declared invalid.

The intent of the statute was to guard against defeating patents, by the setting up of a prior invention, which had never been reduced to practice. If it were the mere speculation of a philosopher or a mechanician, which had never been tried by the test of experience, and never put into actual operation by him, the law would not deprive a subsequent inventor, who had employed his la bour and his talents in putting it into practice, of the reward due to his ingenuity and enterprise. But if the first inventor reduce his theory to practice, and put his machine or other invention into use, the law never could intend, that the greater or less use, in which it might be, or the more or less widely the knowledge of its existence might circulate, should constitute the criterion, by which to decide upon the validity of any subsequent patent for the same invention. I hold it, therefore, to be the true interpretation of this part of the statute, that any patent may be defeated by shewing, that the thing secured by the patent, had been discovered and put in actual use, prior to the discovery of the patentee, however limited the use or the knowledge of the prior discovery might have been.*

Bedford vs. Hunt. 1 Mason, 305

The principles enforced by Mr. Justice Story, in the above case, are recognised in the case of Evans vs. Eaton; 3. Wheaton, 513-514, where Mr. Chief Justice Marshal observed, that without a critical inquiry into the accuracy, with which the term invention or discovery may be applied to any other than the first inventor, the court considers this question as completely decided by the 6th section of the general patent act. That declares that if the thing was not originally discovered by the patentee, but had been in use, or had been described in some public work, anterior to the supposed discovery of the patentee, judgment shall be rendered for the defendant, and the patent declared void.

Admitting the words "originally discovered," to be explained or limited by the subsequent words, still if the thing had been in use, or had been described in a public work, anterior to the supposed discovery, the patent is void. It may be that the patentee had no knowledge of this previous use, or previous description; still his patent is void: the law supposes he may have known it.

An invention which can entitle a man to a patent, must be "useful," as well as "new." But by "useful" is meant, not an invention in

all cases superior to the modes now in use for the same purpose, but "useful" in contradistinction to frivolous and mischievous inventions. This point was determined in the case of Francis C. Lowell vs. Winslow Lewis.*

This was an action on the case for the infringement of a patent right. In the year 1813, Mr. Jacob Perkins obtained a patent for a new and useful invention in the construction of pumps; and afterwards assigned his interest therein to the plaintiff. The defendant became the assignee of a similar patent, taken out in 1817, by a Mr. James Baker; and it was for the constructing and vending pumps under this second patent, that the action was brought. The principal object of both the inventions, was, by dispensing with the box used in the common pumps, to obtain a larger water way. To effect this, Perkins so constructed the valves of his pump, that they completely filled the area of the shaft, and fell upon its sides, in the same manner, as by the old construction, they did upon the box; thus leaving the whole of the area, excepting that occupied by the valves themselves, for a water way. The valves were

* 1 Mason's Rep. 182.