140. The Caligraph uses a separate type lever and key for each letter,

and by a system of compound key levers the touch is rendered easy, even, and elastic, and perfect alignment and freedom from noise are among the objects sought in its mechanical construction. [Illustration: FIG. 140.--NEW CENTURY CALIGRAPH.] Next among the earlier typewriters is to be mentioned the “Hammond,” made under the patents to J. B. Hammond, No. 224,088, Feb. 8, 1880, and 290,419, Dec. 18, 1883. A distinguishing feature of the machine is that the printed work is in full view, so that the operator can see what he is doing. The impression is made by an oscillating type wheel, to which a variable throw is imparted by the key letters to bring any desired letter into printing position. When the letter is brought into printing position a hammer, arranged in the rear of the sheet of paper, is made to force the latter against the type to produce the impression by the same movement of the key that brought the type wheel into printing position. [Illustration: FIG. 141.--SMITH-PREMIER TYPE BAR RING.] Of later machines, none has met with more popular favor than the Smith-Premier, manufactured under the patent to A. T. Brown, No. 465,451, Dec. 22, 1891, and others. A leading feature of this is the type-bar ring of its printing mechanism. In all typewriters accurate location of the impression is essential to proper alignment of the letters, and proper alignment is the _sine qua non_ of typewriting. The old pivoted type bars were liable to wear at the joint, and the slightest looseness at this point would so multiply the lateral play at the end carrying the type that the letters would soon become irregularly placed and out of alignment. In the Smith-Premier this is reduced to a minimum by making a short type bar, and arranging each upon an oscillating rock shaft, the bearings at whose ends are so widely separated as to permit little or no lateral play in the type bar. A view of this type bar ring with tangentially arranged rock shafts disposed in circular series is seen in Fig. 141, while the full machine is given in Fig. 142. In this latter view there is also shown the cleaning brush for quickly cleaning at one operation all of the types of the outer ring. It is simply a circular brush mounted upon the end of a tool resembling a carpenter’s brace, and is a useful and convenient adjunct to the machine. [Illustration: FIG. 142.--SMITH-PREMIER AND CLEANING BRUSH.] In 1891 the “Densmore” typewriter first made its appearance before the public. It was named after James and Amos Densmore, who had been connected with typewriting interests from the time of Sholes’ first practical machine. The Densmore is made under patents to A. Densmore, No. 507,726 and 507,727, of Oct. 31, 1893. It has ball-bearing type bar joints, giving accurate alignment and light key action, the platen rolls to show the work, and the carriage locks at the end of the line, protecting the writing. Noted for its clear, sharp print, the “Yost” typewriter comes in for its share of praise. It is made under the patent to Felbel and Steiger, March 26, 1889, No. 400,200. It does not employ an inked ribbon interposed between the type and the paper, as do most typewriters, but its type-bearing levers, when at rest, occupy a position in which the type are all arranged within and bear against a circular inking ring or pad, and when a key is struck, its lever, by a peculiar and ingenious movement, leaves the inking pad, moves inward and backward toward the center, and then rises and strikes an upwardly directed blow in the center, and prints the letter on the paper. As the printing is done directly from the type, the letters are formed with sharp and clear outlines that give beauty and neatness to the print. Alignment is insured by a center guide hole through which the type end of the lever passes in striking the paper. Among machines of simple organization may be mentioned the Blickensderfer, which is a wonderfully simple and effective little machine, first made under the patent to Blickensderfer, No. 472,692, April 12, 1892. Like the Hammond, it belongs to the class of typewriters which employ a rotary type wheel, which is given a variable throw, from the depression of the keys, to bring the proper letter into printing position; but unlike the Hammond, its type wheel advances to contact with the paper, a little felt ink-roller being brought into contact with the type wheel to ink it as the latter moves. The printed work is in full view, the line spacing may be varied to any fractional adjustment, and the action is quite free from noise. With its mechanism reduced to the fewest and simplest parts, the whole machine weighs only six pounds, and it differs in many respects from the ordinary typewriter. Since its