868 FEDERAL REPORTBB. �filled with fluid tamping more than the entire depth of the ■well, as they were in 1864, �Now any operator with common sense, having knowledge of oil wells and having Eoberts' patent before him, and thus being informed of the object which it seeksto secure bywater tamping, cannot fail to see that he accomplishes ail the patent proposes, securea ail the tamping needed by a column of fluid wholly below the casing, and that a column permit- ted to corne up to the surface of the ground would be not merely useless but positively hurtful. He would be no skil- ful operator if he did not perceive that Eoberts intended no unnecessary filling, when his avowed purpose was to use the water only for the purpose of confining the efïect of the explosion to the vicinity of the point at which the torpedo was placed. We must hold, therefore, that the averment of the bill that the patent has been infringed by the defendant, and that he has been using the process which belongs exclusively to the complainants, is sustained, and we shall decree accord- ingly. �We pass next to the charge made in the bill that the de- fendant has infringed patent No. 47,458, granted on the twenty-fifth of April, 1865, to Edward A. L. Eoberts, and assigned to the complainants. That patent was, as we have heretofore stated, for a new and useful improvement in apparatus for exploding gunpowder, or other explosive ma- terial, in artesian or other similar wells. To understand the device it is neeessary to notice both the object sought to be accomplished and the manner contrived for obtaining it. The evil sought to be overcome is thus described in the specifica- tion. It has always been found difficult to explode gun- powder in a vessel in the water several hundred feet below the surface, and at any given point above the bottom of an artesian well, for two reasons — First, that the powder is lia- ble to become dampened from exposure to the water about the place where it is eonnected with the machinery for igniting it; and, second, such machinery, being usually eonnected with the top of the vessel containing the powder, which is usually ����
