which had been cut up to subserve the necessities of its occupants, all engaged in dealing in gold and stocks. It had one main entrance from the street to a hallway, from which entrance to the offices of two prominent broker firms was obtained. Each firm had its own army of boys, numbering from twelve to fifteen, whose duties were to ascertain the latest quotations from the different exchanges. Each boy devoted his attention to some particularly active stock. Pushing each other to get into these narrow quarters, yelling out the prices at the door, and pushing back for later ones, the hustle made this doorway to me a most undesirable refuge from an April shower. I was simply whirled into the street. I naturally thought that much of this noise and confusion might be dispensed with, and that the prices might be furnished through some system of telegraphy which would not require the employment of skilled operators. The conception of the stock ticker dates from this incident." Mr. Callahan's first idea was to distribute gold quotations, and to this end he devised an "indicator." It consisted of two dials mounted separately, each revolved by an electromagnet, so that the desired figures were brought to an aperture in the case enclosing the apparatus, as in the Laws system. Each shaft with its dial was provided with two ratchet wheels, one the reverse of the other. One was used in connection with the propelling lever, which was provided with a pawl to fit into the teeth of the reversed ratchet wheel on its forward movement. It was thus made impossible for either dial to go by momentum beyond its limit. Learning that Doctor Laws, with the skilful aid of F. L. Pope, was already active in the same direction, Mr. Callahan, with ready wit, transformed his indicator into a "ticker" that would make a printed record. The name of the "ticker" came through the casual remark of an observer to whom the noise was the most striking feature of the mechanism. Mr. Callahan removed the two dials, and, substituting type wheels, turned the movements face to face, so that each type wheel could imprint its characters upon a paper tape in two lines. Three wires stranded together ran from the central office to each instrument. Of these one furnished the current for the alphabet wheel, one for the figure wheel, and one for the mechanism that took care of the inking and printing on the tape. Callahan made the further innovation of insulating his circuit wires, although the cost was then forty times as great as that of bare wire. It will be understood that electromagnets were the ticker's actuating agency. The ticker apparatus was placed under a neat glass shade and mounted on a shelf. Twenty-five instruments were energized from one circuit, and the quotations were supplied from a "central" at 18 New Street. The Gold & Stock Telegraph Company was promptly organized to supply to brokers the system, which was very