Soon after the advent of the Hammond, another important typewriter issue arose--that of single versus double keyboard. The first double-keyboard machine was the Caligraph, placed on the market in 1883, an enterprise upon which Yost entered after it became evident that he could no longer retain his interest in the Remington. The Caligraph was devised under the direction of Yost, principally by a skilled German mechanic named Franz X. Wagner, who afterwards won prominence as the inventor of the Underwood Typewriter. Yost's aim was to construct a typewriter which would evade the Remington patents, but, failing in this, he was subsequently granted a license. In after years the Smith Premier became the leading double-keyboard machine. This machine, the invention of Alexander T. Brown, was placed on the market in 1890 by Lyman C. Smith, the gun manufacturer of Syracuse, and during the next few years attained a wide popularity. It was urged in behalf of the double-keyboard machine that the key for every character made its operation easier and simpler for the beginner. The construction, however, was more complicated, because it doubled the number of type bars and connecting parts, and there was a further disadvantage in the enlarged keyboard, which time made evident. The double keyboard would probably have yielded to the shift key sooner or later, but it was the advent of the touch method of typewriting which really settled the matter. For use in connection with the touch system, the compact keyboard of the shift-key machine proved so obvious an advantage that the double keyboard lost ground rapidly and machines with this keyboard began in time to disappear from the market. The present Smith Premier Typewriter, invented by Jacob Felbel, is a shift-key machine of standard design. Another early issue in typewriter construction concerned the relative merits of the ribbon and the inking pad. This brings us to the last enterprise of G. W. N. Yost, which he undertook after severing his connection with the Caligraph. In 1888 Yost brought out the machine, developed by Alexander Davidson, Andrew W. Steiger and Jacob Felbel, that ever since has borne his name. The most notable departure of the Yost Typewriter from the standard design was the elimination of the ribbon and the use instead of an inking pad, on which the face of the type rested. The first Yost was a double-keyboard machine, but later models embody the shift-key principle. Of late years this type of machine has been hardly known on the American market, although it has always enjoyed a considerable sale in Europe.