The type-printing telegraph was coeval with the dial, and originated with Morse and Vail as early as 1837. The printing of the characters is effected in various ways; sometimes by clockwork mechanism and sometimes by the direct action of an electromagnet. Wheatstone exhibited one in 1841. House of Vermont invented in 1845-1846 the first printing telegraph that was brought into any extensive use in the United States. Then followed that of David E. Hughes of Kentucky in 1855, aided by his co-inventor George M. Phelps of Troy, New York, and which was subsequently adopted by the French government, by the United Kingdom Telegraph Co. of Great Britain, and by the American Telegraph Co in the United States. The system was subsequently greatly improved by Hughes and others. Alexander Bain of Edinburgh in 1845-46 originated the modern automatic chemical telegraph. In this system a kind of punch was used to perforate two rows of holes grouped to represent letters on a strip of paper conducted over a metal cylinder and arranged so as to permit spring levers to drop through the perforations and touch the cylinder, thus forming an electrical contact; and a recording apparatus consisting of a strip of paper carried through a chemical solution of an acid and potash and over a metal roller, and underneath one or two styles, or pens, which pens were connected by live wires with the poles of two batteries at the sending station. The operation is such that colored marks upon the paper were made by the pens corresponding precisely to the perforations in the strip at the sending station. Siemens, Wheatstone and others also improved this system; but none of these systems have as yet replaced or equalled in extensive use the Morse key and sounder system, and its great acoustic advantage of reading the messages by the click of the instrument. The type-printing system, however, has been recently greatly improved by the inventions of Howe, C. L. Buckingham, Fiske and others in the United States. Special contrivances and adaptations of the telegraph for printing stock reports and for transmitting fire alarm, police, and emergency calls, have been invented. The erection of tall office and other buildings, some to the height of more than twenty stories, made practicable by the invention of the elevator system, has in turn brought out most ingenious devices for operating and controlling the elevators to insure safety and at the same time produce economy in the motive power.