This was a bill in equity filed by Wallick, the appellee, to restrain the infringement by Cantrell & Petty, the appellants, of letters patent granted to Wallick, dated May 25, 1875, for an 'improvement in apparatus for enameling mouldings,' on an application filed October 16, 1874. The specification stated the object of the invention to be 'a rapid and economical production of enameled mouldings.' It appears from the record that the mouldings referred to are those which, after being enameled, are gilded and used for picture and mirror frames, and other like purposes. In order to prepare the moulding to receive and retain the gilding, it is necessary to enamel the surface to be gilded with a composition made of glue and whiting. Long before the date of the plaintiff's application the method of doing this was by passing the moulding through a vessel containing the enameling material, the vessel having, at its opposite sides and in the same line, apertures of the shape of a section of the moulding, and large enough to permit the moulding to pass through, and leave a proper quantity of the enamel to pass out with and adhere to it. As early as October, 1851, a patent had been granted to Robert Marcher for an improvement in machinery for enameling mouldings. In Marcher's contrivance the bottom of the box or hopper which contained the enameling composition was left open. The opposite sides of the box were made with apertures of suitable size and shape for receiving the end of the moulding, and when the end of the moulding was thrust through both the apertures the moulding formed the bottom of the box. The result was that on passing a moulding through the box its face was enameled, but its back, which did not come in contact with the composition in the box, was not. The means used to drive the mouldings through the box were not covered by this patent; but this was done sometimes by hand and sometimes by passing them between revolving feed-rollers. The latter became the more common method. In order to give a good enamel it was necessary to pass the moulding through the box several times. According to the contention of the plaintiff, this was the state of the art when he invented the device covered by his patent.
The specification of the plaintiff's patent stated that in enameling certain forms of moulding, for instance, the mouldings shown in Figs. 2 and 3 of the drawings, feed-rollers could not be used for passing the mouldings through the Marcher box without disturbing the coats of enamel on which the upper feed-roller must bear. It then proceeded thus: