Page:Federal Reporter, 1st Series, Volume 4.djvu/344

 330 FEDERAL REPORTER, �"Third. The metliod herein deseribed of feeding a lubricant hy means of hydrostatio pressure operating through devices substantially as herein shown and explained." �The second and third claims only are said to have been infringed. �The defendant's device bas a vertical instead of a horizon- tal cylinder, bas no piston, but the oil and water are sepa- rated by the difference of their specifie gravities. I assume, what is denied by the defendants, that the principle of its device is solely that of hydrostatic pressure. It may also be assumed that Siebert first introduced this principle in an automatio oiler of steam-engines. The important question in the case seems to me to be the validity of the second and third claims of the re-issue, if those claims are to receive the construction which would naturally be given to the language which is used, �When Siebert applied for his original patent in 1869 he was manifestly ignorant that the principle of hydrostatic pressure was contained in his device. This is manifest from the entire specification, which attributes the action of the piston, in forcing the oil through the delivery cock, entirely to the pressure of the steam admitted through the cock at tLe base of the verticle pipe. For example, the patentee says : "A cock admits steam behind the piston, and forces it slowly forward, while another cock, at the opposite end of the cylinder, allows the taUow to pass to its destination. At the back of the cylinder is the cock. G, which admits the steam, by the pressure of which the piston is forced along." There is no mention in the claim of the vertical pipe, or of hydrostatic pressure. Indeed, the vertical pipe did not appear in the drawings, though it was shown in the model. Subsequent investigations having led Siebert to discover, in May, 1879, the value of hydrostatio pressure, "he caused to be made a new arrangement, by which the lubricant reservoir was made to stand vertically, instead of horizontally, as in his first invention, and hydrostatic pressure was applied near its base, at. the bottom of the lubricant. For this arrange- ment he took out his patent of February, 1871. The princi- ����