A bill was filed by the appellant in this case against the appellee, complaining that the latter had infringed, and continued to infringe, certain letters patent granted to one John J. Schillinger, and which had been assigned for the state of California to the complainant. The patent was for an improvement in concrete pavement, and was originally issued July 19, 1870, and reissued May 2, 1871. The improvement, as described in the reissued patent, consisted in laying the pavement i detached blocks, separated from each other by strips of tar paper, or other suitable material, so as to prevent the blocks from adhering to each other. As stated in the specification, 'the paper constitutes a tight water-proof joint, but it allows the several blocks to heave separately from the effects of frost, or to be raised or removed separately, whenever occasion may require, without injury to the adjacent blocks.' Prior to this invention, it seems, from the statement of facts made by the court, that concrete pavements had been made in one continuous sheet, without being divided into blocks, whence it was liable to crack in irregular directions, and to break up in such a manner as to render it useless. The specification of the reissued patent contained the following clause: 'In such cases, however, where cheapness is an object, the tar paper may be omitted, and the blocks formed without interposing anything between their joints as previously described. In this latter case the joints soon fill up with sand or dust, and the pavement is rendered sufficiently tight for many purposes, while the blocks are detached from each other, and can be taken up and relaid, each independent of the adjoining blocks;' but this clause had been disclaimed by filing a disclaimer in the patent-office. The patent had two claims, as follows: '(1) A concrete pavement laid in detached blocks or sections, substantially in the manner shown and described; (2) the arrangement of tar paper, or its equivalent, between adjoining blocks of concrete, substantially as and for the purposes set forth.'
The defendant answered the bill, denying the validity of the patent and denying infringement, and declaring that the concrete pavements made by him were made under and in accordance with certain letters patent granted to one J. B. Hurlburt, April 20, 1875, the process of which is described in the answer, as follows:
'The said Hurlburt invention is a novel method of forming blocks of artificial stone or cement pavement, whereby they are prevented from becoming uneven by sinking below or rising above a common plane, and consists in beveling the edges of the blocks so that they will measure more across their under side in one direction and less across their upper side than across their under side in the other or opposite direction; and also consists in the novel construction of a forming frame, whereby the blocks are beveled as devised by using the different sides of the frame alternately; and also in the novel construction of a parting strip, whereby the colors are kept separate, showing a straight line between the blocks and while forming their edges in actual contact, the same strip being of great service to rest a straight edge upon while beveling the block in process of formation, and that by said invention the process of laying cement pavements saves from 10 to 15 per cent. in cost of labor over any other known process, entirely dispenses with tar paper or any equivalent, and all other expensive superfluities, and makes a close-beveled joint; it being impossible to raise, or attempt to raise, any separate piece of work without chiseling and digging and materially unjuring adjacent work.'