History of the Typewriter

— 15 — of the mainspring is very different when the carriage is in a position to write at i on the scale, to what it is when 65 or 70 is reached. This fact has been taken into consideration in many machines, and we shall find here- after that in the National, the Ideal, and so on, means have been taken for securing -a centre-driven carriage. The escapement was also re-modelled. Instead of having two dogs, one rigid and the other loose, playing in a single rack, the Caligraph introduced a single dog, Fig. 58 working between two racks, the one loose and the other rigid. The space-bars, also, were a novelty, and were pro- bably the first serious attempt to bring about an all-finger style of operation. Two such bars were provided, one at each side of the machine, and it was intended that these should be depressed by the little fingers. The type-bars were provided with adjustable nuts and bolts, for taking up wear and recovering alignment and in the later models an improved ribbon feed, per- mitting of a lateral as well as a sideways action was used. It is interesting, also, to note that the platen of the Caligraph was not round, as in the Remington, but was planed off into a series of facets. The object was to secure a flat surface for a perfectly flat faced type to strike upon. Later inventors got over this difficulty by hollowing out the type so as to make them conform to the curve of the platen. The Caligraph was made in several numbers, and an old No. i in our possession seems to justify the title being given to the machine of “ The machine that won’t wear out.” This machine used capitals only, but others incorporated full keyboards.