in an equity suit can be permitted to prove that the invention described in the prior patent, or the invention described in the printed publication, was made prior to the date of such patent or printed publication, for the reason that the patent or publication can only have the effect as evidence that is given to the same by the act of Congress. Unlike that, the presumption in respect to the invention described in the patent in suit, if it is accompanied by the application for the same, is that it was made at the time the application was filed; and the complainant or plaintiff may, if he can, introduce proof to show that it was made at a much earlier date.

Improvements, it seems, were made by the complainant in drilling and bolt-tapping machines, called in the introductory part of the specification a new and improved drilling and screw-cutting machine, for which he, on the 20th of January, 1863, received letters-patent in due form; and the record shows that on the 19th of February, four years later, he surrendered the same, and that a new patent, being the reissued patent in suit, was granted to him for the same invention.

Special reference is made in the specification to the figures given in the drawings for a description of the invention, and they show, beyond doubt, what the specification alleges, that the invention relates to a novel and improved arrangement of the parts of a machine constructed and designed for the purpose of drilling and cutting screws; nor is it doubted that the allegation of the patentee is true, that it affords to the operator engaged in cutting screws considerable advantages beyond what he would obtain by the use of the ordinary hand-machine.

Inventors, before they can receive a patent, are required to file in the Patent Office a written description of their invention, and of the manner and process of making and using the same, in such full, clear, concise, and exact terms as to enable any person skilled in the art to make, construct, and use the same.

Pursuant to that requirement, the patentee gave a particular and full description of all the operative devices of the machine, even to the minutest, and of the function performed by each, and of the mode of operation of the whole when the machine is put in motion, including the devices employed when the machine is operated by steam. The devices may be divided

into two classes: 1. Those employed to do the work. 2. Those employed to operate the machine, whether by steam or by hand.

Constituted, as the machine is, of numerous devices operat. ing as a whole, it is scarcely possible to define its operations without first taking into the account its separate parts. Of course it has a frame secured to some appropriate fixture, which constitutes, directly or indirectly, the support of all the parts of the machine. Operated, as the machine is, by power, which may be either steam or hand power, it follows almost necessarily that it has a shaft, which in this machine is fitted horizontally in the upper part of the frame, with a fly-wheel at one end and a bevel-pinion at the other, which latter device gears into the bevel-wheel shown in the drawings, the shaft of which is fitted in suitable bearings on the upper part of the frame and at right angles with the main shaft, as shown in the second figure of the drawings, the outer end of the last-named shaft being provided with a crank.

Besides the pinion already mentioned, there is another, called a bevel-pinion, which also gears into the same wheel, the statement being that it is fitted loosely on the shaft of the wheel in such a manner that the shaft may rise and fall independently of the wheel, and the latter be made at the same time to rotate the shaft, which is tubular at its lower end, and is provided with a set-screw, by which a drill or screw-cutting die may be secured in it.

In addition to that, there is a vertical screw, which works in a nut on the upper part of the frame, the lower end of the screw being connected by a swivel-joint with the upper end of the tubular shaft. On the screw above the nut there is placed a ratchet, fitted on the screw in such a manner that when turned it turns the screw, and at the same time admits the latter to rise and fall under the action of the nut.

Speaking of the ratchet, the patentee states that it is turned by means of a pawl which is connected by a pivot to the arm, the latter being attached to the frame of the machine by a pivot. Connected with the arm is a spring, which has a tendency to keep the outer or free end of the pawl in contact with the face of the wheel, which is of such a shape as to form a cam

and operate the pawl, so that the latter will turn the ratchet and cause the ratchet as it rotates to turn the screw, the ratchet causing the same to descend as it is turned, so that the tubular shaft will be forced down and the drill fed to its work.

Such is the described mode of operation of the working de vices when the motive power is steam; but the patentee states that it is easy to throw the pawl back so that it can no longer be operated by the cam, in which event the drill must be fed to its work by hand, which is done by turning the screw by means of the handle attached to the wheel on top of the screw.

Next follows the description of that feature of the machine which may be denominated the screw-cutting apparatus. Brief as the description is, it is obviously sufficient to justify the patentee in his claim that it is both new and useful. He commences by stating that the base of the frame has an oblong opening made through it vertically to receive the shanks of the jaws constituting the vice, one of which has the ends of the yoke, so called, bolted to it. Two screws are also described, one of which passes through the semicircular end of the yoke, and the other passes into the jaws of the vice. for the purpose of clamping or holding the

These jaws are rods on which

screws are to be cut. Such rods are clamped firmly between the jaws by turning the screw that passes through them which constitutes the vice, the screw-cutting die being screwed in the lower end of the tubular shaft, and the pawl being disengaged from the ratchet. No feed movement is required in the operation, as the jaws and rod rise and fall under the action of the die, the shanks of the jaws serving as guides. When more speed is required for either drilling or screw-cutting than can be obtained by turning the bevel-wheel, it is accomplished by applying additional power to the main shaft, which shows that the machine is adapted to both heavy and light work.

Service was made; and the respondents appeared and filed an answer setting up several defences, as follows: 1. That the complainant is not the original and first inventor of the alleged improvement. 2. That the alleged improvement, in all its parts, was fully described in the several patents, printed publications, and rejected applications for patents set forth in the

answer, prior to the alleged invention thereof by the complainant. 3. That the improvement secured by the reissued patent is not for the same invention as that embodied in the original patent. 4. That the alleged improvement was in public use and was known to divers persons in the United States prior to the alleged invention thereof by the patentee, more particularly set forth in the amended answer subsequently filed by leave of court. 5. That the respondents have not infringed the alleged invertion, and that if they have, the complainant has not suffered any damages by such infringement.

Proofs were taken, hearing had, and the court entered a decree in favor of the complainant, and sent the cause to a master to compute the gains and profits of the infringement made by the respondents. Prompt report was made by the master, to which both parties excepted; but it is wholly unnecessary tc notice the exceptions of the complainant, as he did not appeal; nor is it necessary to give much consideration to the exceptions filed by the respondents, as the assignment of errors varies materially from the exceptions taken to the master's report.

Both parties appeared, and were heard; and the court confirmed the report of the master as to the amount awarded, and entered a final decree that the complainant recover of the respondents the sum of $290 and costs; from which decree the respondents appealed to this court.

Since the appeal was entered here the respondents have filed the following assignment of errors: 1. That the Circuit Court erred in finding that the respondents had infringed the first claim of the reissued patent. 2. That the court erred in finding that the complainant was the original and first inventor of the improvement specified in the second claim of the patent. 3. That the court erred in finding that the respondents had infringed the second claim of the patent. 4. That the court erred in finding that the respondents had infringed the third claim of the patent. 5. That the court erred in finding that the complainant was the original and first inventor of the improvement specified in the fourth claim of the patent. 6. That the court erred in finding that the respondents had infringed the fourth claim of the patent. 7. That the court erred in adjudging that the reissued patent is a good and valid

patent. 8. That the court erred in confirming the fifth finding in the report of the master. 9. That the court erred in the construction given to the reissued patent.

Annexed to the specification are the claims of the patent, which are as follows: 1. The arrangement of the three bevelwheels in such a manner that the tubular shaft may be revolved with more or less speed and power for the different purposes to which the machine may be adapted. 2. The automatic feed arrangement, consisting of the ratchet, pawl, spring, and cam, whereby the drill is fed to its work, the arrangement being so made that it can be detached and the drill fed by hand. 3. He also claims the vice for holding the rods for making screws, in combination with the machine, the vice consisting of the described jaws and the described screw arranged in the base of the frame. 4. Finally, he claims the combination of the tubular shaft and the described vertical screw with the pinion and nut, whereby the rotary motion and the necessary feed is given to the drill, as described in the specifica tion.

Cases arise not unfrequently where the actual invention de scribed in the specification is larger than the claims of the patent; and in such cases it is undoubtedly true that the patentees in a suit for infringement must be limited to what is specified in the claims annexed to the specification, but it is equally true that the claims of the patent, like other provisions in writing, must be reasonably construed, and in case of doubt or ambiguity it is proper in all cases to refer back to the descriptive portions of the specification to aid in solving the doubt or in ascertaining the true intent and meaning of the language employed in the claims; nor is it incorrect to say that due reference may be had to the specifications, drawings, and claims of a patent, in order to ascertain its true legal construction. Brooks et al. v. Fisk et al., 15 How. 215.

Apply that rule to the case, and it follows that there is no substantial variance between the claims of the patent and the description of the invention or inventions described in the specification.

In construing patents, it is the province of the court to de termine what the subject-matter is upon the whole face of the