the patent of the complainant, or ever invaded any of his rights, as alleged in the bill of complaint.

Proofs were taken, the parties heard, and the Circuit Court having overruled both defences, sent the cause to a master to ascertain what amount the complainant was entitled to recover. Hearing was had before the master, and he made a report, as required by the decretal order. Exceptions were filed by the respondents, who were again heard before the Circuit Court in support of their motion to set aside the master's report. Modifications of an important character were made by the Circuit Court in the report of the master, both in respect to the amount adjudged to the complainant and in respect to the portions to be paid by the respective respondents, the decree being that the complainant do recover of the three respondents the sum of $1,961; and also against the first two in the sum of $3,748.28, with interest and costs, as therein specified.

Seasonable appeal was taken by the first-named respondent, and since the appeal was entered here he has filed the following assignment of errors: 1. That the Circuit Court erred in holding that the patent of the complainant is good and valid. 2. That the Circuit Court erred in holding that the respondents have infringed the claims of the complainant's patent.

Patented time detectors for watchmen were known in the art prior to the date of the patent described in the bill of complaint, and it appears that the complainant, at a certain period anterior to that date, became the owner of such a patent, and that he surrendered the same, and that it was reissued in his name for the then unexpired portion of the term. Certain alterations were made in the specification of the reissue, and, as there described, the invention provided a watch for the watchman, which he carried with him in his rounds, so constructed that, by the insertion of a key kept at each of the stations he was required to visit, he could make a record within the watch indicating the several stations visited, with the precise time of each visit, and the order in which the respective visits were made. Each watch was provided with a lock, so that the watchman had no access to its interior, and as the record of each station could only be made by the peculiar key that belonged to such station, which was there made fast, the

watchman could not deceive his employers by making a false record.

All these several functions were effected by using a watch or small portable clock movement enclosed in a strong case, the lid of which could be locked and the key kept by the employer. Like a watch it had an arbor upon which the hour-hand was placed, and a drum was attached so as to revolve as the hourhand revolved, the purpose of which was to carry the roll of paper to receive the marks indicating the time of each visit. By marks on the paper it was divided into spaces corresponding in their position, relatively as respects the centre of the watch, to the hours and minutes of the watch dial, and by lines drawn lengthwise it was also divided into spaces corresponding in number to the number of markers to be used in effecting the patented result.

Exterior to the watch-movement, but within the case, there were placed small steel bars or springs, terminating each in a point bent at right angles, while the other end was fixed firmly to the circular plate or frame of the watch-movement. These springs were placed and held in a gang, one above another, so that the points were in a row perpendicular to the watch face, at and exterior to the point on the dial of the watch indicating the hour of twelve, and each point was directly opposite one of the longitudinal spaces in the strip of paper around the circumference of the drum.

What the inventor desired to accomplish was to show the exact time of each visit of the watchman, and it is obvious that if the point of one of the springs is pressed inward upon the revolving drum it will perforate the paper within its proper longitudinal division, and that the perforation will show the hour and minute at which it was made; and in order to permit such perforation without injuring the steel point the periphery of the drum was channelled by narrow longitudinal grooves beneath each of the spaces in the paper placed around the drum to receive the marks. Keys were also provided varying from each other in the location and width of the bit and in the number of the bits, so that when one was inserted in the keyhole contiguous to the steel spring, and turned, it would press one of the springs inward upon the paper and make the required

perforation, while another would press two springs and make two perforations, another three, and so on, as more fully set forth in the specification. Buerk v. Valentine, 9 Blatchf. 479.

Since the term of that patent expired, the complainant has obtained a patent for the invention in controversy in this case, which, as he admits, is for the same purpose as the other, but which he insists is a valuable improvement in accomplishing the purpose for which both inventions were made. In its main features the new improvement consists in dispensing with the drum entirely and the paper wound around its circumference. Instead of that it attaches a circular disk to the arbor of the hour-hand to revolve therewith, and attaches thereto a circular flat paper dial of larger diameter divided by vertical lines, corresponding with the hours and minutes of a watch dial, and having a portion of its exterior divided into spaces by circular lines drawn at uniform distances, and corresponding to the location of certain steel points as the paper disk is revolved. Beneath the circular plate forming the support or frame of the watch-movement the gang of steel bars or springs is firmly attached to the plate in such position that the points are in a straight line radial to the centre, and over each point is a hole in the plate so that each can be pushed upward, the point thereof passing through the hole sufficiently to perforate the paper dial in the space corresponding to the point of the spring. Over the row of holes is placed a small strip of metal, called a fixed index, which is fastened to the circular plate or frame of the watch, and extends towards the centre of the disk, and is raised sufficiently above the revolving disk to permit the paper dial to revolve freely under it and over the holes through which the spring-points are to rise, and to prevent injury to these points holes are made in its under surface opposite each point, into which the points as they rise may enter, and then by the power of the spring be withdrawn to their respective positions below the plate. Devices, called keys, of a like character to those used in the prior invention, are provided, to be inserted in a key-hole so located that the bit of the keys when turned will force the springs upwards instead of inwards, as in the other apparatus previously explained. Perforations are made by the combination in the exterior portion of the revolving

paper dial, which indicate the precise hour and minute when it was made, and the particular key that was employed, with all the variations accomplished by the devices described in the specification of the prior patent.

Attempt is made in argument to support the first assignment of error chiefly by reference to three exhibits introduced in evidence by the respondents, which were known and used by the public prior to the date of the patent described in the bill of complaint. They are the patent of Schwilgue, the patent of Rowbotham, and the patent of Nolet.

Before entering upon a separate examination of these several patents, it is proper to remark that it is not pretended that any one of them embodies the entire invention secured to the complainant in his letters-patent. Nothing of the kind is pretended, but it is insisted that each contains some feature, device, or partial mode of operation corresponding in that particular to the corresponding feature, device, or partial mode of operation exhibited in the complainant's patent.

Suppose that is so, still it is clear that such a concession cannot benefit the respondent, it being conceded that neither of the exhibits given in evidence embodies the complainant's invention or the substance of the apparatus described and claimed in his specification. Where the thing patented is an entirety, consisting of a single device or combination of old elements incapable of division or separate use, the respondent cannot escape the charge of infringement by alleging or proving that a part of the entire invention is found in one prior patent, printed publication, or machine, and another part in another prior exhibit, and still another part in a third exhibit, and from the three or any greater number of such exhibits draw the conclusion that the patentee is not the original and first inventor of the patented improvement. Bates v. Coe, 98 U. S. 31, 48.

Authority is given to a defendant in an action at law or to a respondent in an equity suit to plead or set up in the answer that the patentee is not the original or first inventor of the improvement; but if the plaintiff or complainant introduces his patent in evidence, the burden is cast upon the defending party to prove his defence, which he may do by showing that the

thing patented had been invented or discovered by some other person in this country prior to the alleged invention in the pending suit, or that it had been patented or described in some printed publication in this or any foreign country. Rev. Stat., sect. 4920.

Apply that rule to the facts of the case, and it is clear to a demonstration that neither of the exhibits given in evidence by the respondents constitutes any defence to the charge contained in the bill of complaint. Curtis, Patents (4th ed.), sect. 98.

Similarities may doubtless be shown between certain features of the apparatus invented by Schwilgue and the apparatus patented to the complainant, as contended by the respondents; but they utterly fail to point out the differences, except in one or two particulars. They differ not only in construction, but in the mode of operation, and in almost every particular which gives value to the device as a time detector for watchmen, the foreign patent being much more cumbrous and inconvenient than that of the complainant. Stationary detectors were employed at an early period to secure fidelity in watchmen in making the rounds of their beat in factories or other business establishments. Detectors of the kind were soon followed by portable watch-movements which were carried by the watchman, on which he stamped with ink or other coloring matter the proof of his visit to the several rooms within his beat. Enough appears to show that the patent of Rowbotham was nothing more than an improved apparatus of that class, being evidently so unlike that of the complainant as not to deserve much examination.

Nor is it necessary to enter much into detail in disposing of the other exhibit introduced by the respondents, as it evidently belongs to the same class of detectors as the preceding, and bears little or no relation to the apparatus of the complainant.

Argument to show that the present apparatus of the complainant is substantially different from that described in the expired patent cannot be required, as the comparison already given is amply sufficient to prove that difference to every one not blinded by self-interest or prejudice. Tested by these considerations, it is plain that nothing remains for re-examination but the question of infringement.