HOFFMAN V. TOTJNa. 75 �Hearing on bill, ans-wer and proofa. �This was a bill in equity to restrain the alleged infringe- ment of a patent. The facts are sufficiently stated m the opinion. �Allen H. Gangewer, for complainant. �G. Morgan Eldridge and Wm. Ernst, for respondent. �BuTLEE, D. J. On November 20, 1877, letters patent No. 197,369, for an "improvement in tripod heads for surveyors' instruments," were issued to the complainant, the claims in which are as follows : "First, the combination with the plate A, having central opening a, and the plate G, having the Bocket c, extending through said opening of the bail D, hav- ing threaded neck d, the levelling screw-plate E, having bail g, and the instrument-plate F, having neck c and eocket h, Bubstantially as specified. Second, the combination with the base-plate A, having central opening a, and the socket-plate c, having neck c, of the carrying-plate B, having aperture b, fitting said neck, and the levelling mechanism of a tripod head, substantially as specified. Third, a tripod head, hav- ing a bail and socket-joint for the base plate, in combination with the instrument-plate F, having a spherical bearing g h, concentric with said bail and socket-joint, and levelling-plate E, substantially as specified." �The object of the invention, as stated in the patent, was "to devise a tripod head of such construction that it may be levelled with absolute accuracy and expedition, and may be adjusted horizontally for bringing the center of the instru- ment over a fixed point on the ground, whatever be the na- ture of the same or its inclination." �The bill charges the respondent with infringing this patent. The answer, as originallyfiled, (virtually admitting the valid- ity of the patent,) denies the allegation of infringment; alleges that the respondent's tripod heads are made in pursuance of letters issued to himself on April 20, 1878 ; and, also, that he bas a license from the complainant. By amendment, the validity of complainant's patent is attacked, and his instru- ment declared to be a combination, simply, of those of William ����
