384 FEDERAL REPORTER. �movement. There is a series of holes ail around the dial near its circumference. A pin is inserted into one of these holes and projects from the back of the dial, so that it is brought into contact with the long arm of the lever by the revolution of the dial. The whole lever being rigid, the pin, acting on the long arm, pushes it one side, and so unlatches the cross-bars, which immediately swing out of the sockets, and the door is unlooked. By putting the pin in different holes, the time when it is brought in contact with the lever, and hence the hour for unlocking, inay be varied." �This device was intended merely for unlocking, but Mr. Shepard, one of the defendants' experts, says that "if it was desired to hold this lever out of its locking position for a cer- tain number of hours, and at the same time have it under Buch condition that it would be released and fall into place after a certain number of hours, without returning to the safe to manipulate it, then duplicate pins might be employed and placed in several of the successive holes." The witness is aware that there is no mention in the patent of more than one pin for the disk, but does not think that there is inven- tion in the addition of duplicate pins, and thereafter much strength was spent in the investigation of the earnestly-dis- puted question whether the alterations necessary to make a locking device were compatible with the construction of the Derby mechanism, as shown in the patent and drawings. It is manifest that the patent which was issued in 1858 shows no conception of a locking device; that to add one which shall be efficient, alterations must be made in his mechanism, and that nobody produced a loek of this kind until Little's invention came into being in 1874. Assertions by ingenions and able experts in the year 1880, after invention in safes has been greatly stimulated, of what could have been done by mechanical skill prier to ISTe, do not press with great weight upon my mind. �There is a class of improvements which are plainly and obviously mechanical in their origin. An instance of this class wiU be noticed hereafter. But when the subject of in- vestigation is an alleged invention of complex mechanism, ��� �
