TYPEWRITEKS. 596 TYPEWRITERS. In 1877 an improvement was introduced, wliereby eacli type-bar in the circle was made to carry two characters, adjusted to separate com- mon' centres. By depressing a shift key the car- riage is thrown backward to the second centre, which is adjusted to receive all the capital letters and many other characters placed in relation thereto. Tliis double-alpluibet machine measured fifteen inches along the side, twelve inches across the front, and about nine inches in height, and weiglied about twenty-three pounds. In 1894 an improved model, having a lighter and. stronger paper carriage, was placed upon the market. The shifting movement was accom- plished by a new mechanism, and improvements in the spacing mechanism, greatly increasing the speed of the machine, were also introduced. An automatic ribbon reverse was later included, and many minor points of improvement have been from time to time adopted by the manufacturers. The growing expertness of operators rendered the improvements in speed especially acceptable. This new model writes with seventy-six char- acters in a line seven and a half inches long. Special companion models subsequently intro- duced possess eight.y-four characters, and one can hold paper from standard width to twenty- seven inches for certain special requirements. The Remington may be regarded as the pioneer machine. Its first competitor was the Caligraph, largely promoted by George W. N. Yost, who had for a time obtained a small interest in the sale of the Remington machine in its early years. This machine, like the Remington, had a circular bas- ket of type-bars, and in many respects resembled its rival. In this machine the so-called shift from capital to small letters was done away with, and there was a separate lever and type-bar for each character. Horizontal levers, with which the keys were connected, were also hinged at the front, instead of the back. The carriage was sup- ported, and was adjusted much the same as in the Remington, but was actuated by a torsion spring about a rod extending from the front to the back of the machine frame, where a vertical arm connected with the carriage frame above. The cylinder had a polygonal surface, the impressions being received on the faces. This machine has in recent years been superseded by an entirely new model, known as the New Century, which in- volves in many cases a radical departure from the earlier construction. Mr. Yost retired from the company and introduced another machine, which liears liis name. The Yost does not em- ploy an inked ribbon, like most typewriters, but its type-bearing levers, when at rest, occupy a position in which the types are all arranged with- in and bear against a circular inking ring or pad, and when a key is struck, its lever leaves the inking pad, moves inward and backward toward the centre, and then rises and strikes an upward blow in the centre, and prints the letter on the paper. The first Hammond machine was invented by James B. Hammond in 1880-83. Its central principle was the type-wheel, a favorite device of .John Pratt, who labored for a long time, but unsuccessfully, to make his invention a practical success. The arrangement of the original key- board of the Hammond differed materially from that of the Remington, being almost semicircu- lar. In 1890, however, a new model, termed the Universal Hammond, was introduced, having a keyboard with three banks of keys, like other standard machines. Still later, a light rubber shell or shuttle, supported by a metal backing, was substituted for the wheel. In this latest ma- chine the ninety types are cast in true alignment upon a curved plate of vulcanite, called the 'shuttle.' in the form of an arc of a circle. The backing for the shuttle is a heavy cast-iron ring called ^anvil," and may be compared to a wheel having a slot in the centre of its face in which the steel web of the shuttle slides. This forms a guide for the shuttle in its horizontal move- ments. The anvil is stationary and firmly fixed to a vertical shaft by which it may be raised to bring cither of the three rows of type into the printing position. The depression of a key con- trolling the character to be printed brings that character on the shuttle into position by means of a shuttle arm and a series of index pins, each one of which corresponds to the angular distance of any character from the normal position. The impression of the hammer is at that moment re- ceived by means of a lever, which releases the hammer spring and the carriage and forces the paper against the type on the face of the shuttle. As these shuttles are interchangeable, it is pos- sible for the one machine to produce any num- ber of different alphabets or styles of type. In 1889 the Chicago typewriter was placed up- on the market and at once attracted attention on accovmt of the simplicity of its mechanism and its comparatively low price. It has a longi- tudinally placed steel type-wheel, arranged to be held both longitudinally and circumferentially by stop-pins engaging directly with notches in the ends of the type-wheel. Like the Hammond and other type-wheel machines, the type is inter- changeable and can readily be remoed and re- placed by type of another style or language. In 1889 the Smith-Premier was also placed up- on the market and rapidly assumed its rank among standard machines. This typewriter, like the Remington, is a type-bar machine, but has a separate key for each character, the keyboard be- ing rectangular, with seven banks of keys. A novel feature of the machine is the type-cleaner, a revolving brush, fitted with a threaded shaft which, upon being turned with a detacliable crank, is brought in contact with the type and brushes the entire set. In 1892 the Blickensderfer machine was intro- duced, and, like the Chicago, at once attained great popularity on account of its simplicity and low cost. With the exception of the Blickensder- fer, the machines described were all introduceil prior to 1890. During the closing decade of the century many new machines were brought upon the market, so that at its close there were over 100 dift'erent machines, on which nearly 1700 patents had been granted. Besides the so-called standard machines, there are a large number of 'try' nuichines in use. Typewriters for printing in books have also been invented and have proved very successful. The Elliot & Hatch book typewriter is a well- known example of this class of machines in which the whole carriage and system of type-levers move and the book remains stationary.
