2. SAME-INVENTOR-PRESUMPTION AS TO STATE OF ART.
It is a legal presumption that mechanics interested in upholding or defeating a patent were fully acquainted with the state of the art when they took out their patents. Each is assumed to have borrowed from the other what was first invented or used by the other.
3. SAME COMBINATION OF OLD DEVICES-FORMULA OF "KNOWN SUBSTITUTE."
Where the combination of horizontal fingers and jacks, and the combination of vertical fingers positively attached to jacks, were old, and the complainant claims horizontal fingers positively attached to jacks, the formnla of known substitutes will not apply. .
4. SAME INFRINGEMENT.
The true test of infringement is whether the defendant uses anything invented by the complainant.
5. SAME SAME
In a patent on harness mechanism, for looms, the complainant's device, in which the heddle levers are actuated by horizontal reciprocating bars engaging with hooked levers, held, not infringed by defendants' device, in which they are actuated by a cranked wheel pivoted to a finger connected with them, and engaging with horizontal rotating cylinders.
In Equity.
Causten Browne, for complainant.
Chauncey Smith and B. F. Thurston, for defendants,
LOWELL, C. J. The parties to this suit hold patents for the harness mechanism of looms. That of the complainant was granted to him in 1866 and re-issued in 1874, No. 5,718; and that of the defendants, No. 37,760, was issued to Lucius J. Knowles in 1863. In the plaintiff's loom, the levers which raise and depress the threads of the warp by means of the heddles, are, themselves, moved backward and forward by reciprocating bars placed at right angles to the heddle levers, and engaging with them through small levers, which are pivoted to the heddle levers, and provided with hooks at each end. A pattern chain determines which end of the small lever shall engage with the bar, and, consequently, which way the heddle lever shall be moved. In the defendants' machine, as they now use it, each heddle lever is provided with a rod which is pivoted to it, and is connected by a crank-pin with a toothed wheel; and this wheel is pivoted to an arm, or "finger" as
