446 ^ FEDERAL REPORTER. �right, title, and interest of the assignors in and to the said two patents, proceeds thus : "Together with the right to mod- ifications, improvements, or re-issues thereof, and ail other and similar patents in the United States which maybeissued to us or any one of us, directly or indirectty, in aid of the improvements above specified. * ♦ * And we do hereby covenant and agree to and with the said Stebbins Hydraulic Eleyator Machine Manufacturing Company, each for himself and not one for the other, to make, execute, and deliver to it, the said Stebbins Hydraulic Elevator Machine Manufacturing Company, such other and further assurances, deeds, and transfers as may be necessary or proper for the more effectuai accomplishment of the true intent and purpose of these presents." On the first of February, 1876, letters patent No. 172,896 were issued to the defendant for "improvements in hydraulic elevators," and on the fifteenth of August, 1876, letters patent No. 181,113 vrere issued to him for "improve- ments in hydraulic elevators." �This suit is brought to recover for infringements of patents Nos. 132,111 and 132,112, and to compel the defendant to execute to the plaintiff corporation an assignment of patenta Nos. 172,896 and 181,113. The specification of No. 132,- 111 says: "My invention relates to improvements in that olass of hydraulic elevators which are used for elevating per- Bons and things from one floor of a building to another. My improvement consista of an arrangement whereby the power. of either one or two upright cylinders can be employed for elevating the load according to the weight which it is desired to lift. Heretof ore, when two cylinders have been used for this purpose, the arrangement has been such that the pressure in both cylinders was applied in ail cases, whereas, frequently and in most cases, the power of a single cylinder is sufficient, thua causing a waste of water, which, especially in cities where water is paid for by the gallon, is a heavy and unnecessary expanse. In the foUowing description my invention is fuUy described, reference being had to the accompanying drawing forming a part of this specification, in which figure 1 is a ����
