Page:Federal Reporter, 1st Series, Volume 1.djvu/327

 PAGE V. HOLMES BDBGLAR ALAEM TELEGBAPH 00. 319 �Tiack or retracted to make the circuit again, by a weight attached to an ann, and adjustable thereon. Such weight overbalances the weight of the armature, and draws it away from the magnet whan the circuit is broken. The adjust- ment of the weight or retractUe force is made by moving the weight on a screw thread eut on the arm. In the defendant's apparatus, the retractile force which acts on the armature, to draw it away from the magnet, is a spiral spring, the tension of which spring is made adjustable, by minute adjustments, which can be made while the apparatus is working and with- out stopping it. The weight in the plaiatiffs' patent bas the same extent of adjustable capacity. The defendant's appa- ratus bas the combination of an electro-magnet, an armature, and an adjustable retractor. It also has a set-screw, against which the armature strikes when it is withdrawn from the magnet by the retractile force, such set-serew being adjusta- ble and regulating the length of the vibration of the armature. It is quite clear that the defendant's apparatus infringes the eleventh, twelfth and tlairteenth claims of the plaintiffs' patent, and the plaintiffs' expert so testifies. �It is contended, for the defendant, that the eleventh daim is not infringed, beeause the plaintiffs' weight and the defend- ant's spring are not mechanical equivalents. In the place in which the two are nsed, and in view of the service they perform, it is manifest that they are mechanical equivalents. It is also contended, that the object of making the spring adjustable is to ascertain, by nsing the adjustable functions of the spring, whether the apparatus is in working order originally, and that then the spring is left at the tension fixed upon. But the defendant makes the apparatus adjustable for some purpose, as to the retractile force, and such adjust- ability is confessedly availed of, in setting the apparatus for use originally. The words, "the adjustment," in the eleventh claim, are to be read as meaning the mechanical means of making the adjustment. �It is not really seriously contended that the twelfth daim is not infringed. �In regard to the thirteenth claim, it is contended that, in ��� �