The immense sale of the pianola led piano makers generally to seek to incorporate its prin ciples into their machines, and hence arose the player-piano, which type of instrument has so taken the market, that the demand for an old-style hand-played upright is rapidly reduc ing. Each of the leading manufacturers brought out some form of player-piano that would play music furnished in the roll, and at first each gave a special name to his product. But as there was little difference in the mechanisms, the public came to pay less attention to the i trade names, and all these instruments have come to be classed as player-pianos. After a time it became obvious that it was to the in terest of the trade to have a standard width of music roll, so that music could be run on any player-piano, and a trade agreement was entered into to that effect between leading manufacturers. The typical player-piano has a bellows, operated usually by foot-pedals like those of parlor-organs; also a compensating or equalizing device to govern the air-pressure, which is very necessary; a series of air-tubes to which a current is admitted when a perfora tion of the traveling music-roll uncovers the desired valve; a motor (which may be based on the bellows-power) for moving the paper roll, and a tracker-mechanism for utilizing the air-pressure or vacuum, to strike the keys of the piano itself. There are also controlling levers for regulating the time, by allowing the roll to move slower or faster; also for re winding and for producing the expression. Large player-pianos are made on this prin ciple and fitted with electric motors for use in furnishing automatic music in "movie" theatres, on shipboard, etc., these being com monly called automatic pianos.
In 1914 there were manufactured in the United States 183,368 pianos, of the total value of $62,775,000, this being a slight reduction as compared with the production in 1909, though a gain of over 30 per cent as compared with 1904. The production of player-pianos in 1914
attained two-fifths of the total value, and in 1918 it is estimated that the majority of the pianos are made either with a player embodied in the design or with such attachment. The annual production of music rolls for such pianos in 1918 was over $1,000,000. During the period between 1909 and 1914 the number of upright pianos made in the United States for or with player attachments increased from 34,495 to 88,078, or by 154.6 per cent, and their value increased from $9,275,001 to $20,892,514, or by 118.5 per cent. The number of grand pianos made for or with player attachments increased from 21 in 1909 to 831 in 1914, and their value increased from $28,900 to $413,665. The output of player-pianos in 1914 included 3,352 automatic pianos, valued at $1,373,206.
There were 255 piano factories in the United States in 1914, giving employment to 24,000 persons and paying out nearly $16,000,000 in wages. They purchased that year nearly $30, 000,000 of materials, adding $33,000,000 value in process of manufacture. The leading States in the piano manufacturing industry are Illinois, Indiana, New York, Massachusetts, New Jersey and Michigan.
For further modern in formation consult Spillane, 'History of the American Pianoforte' (New York 1890) • Hip kins, 'History of the Pianoforte' (London 1896) ; Rimbault, 'History of the Pianoforte' (London 1860) ; Paul, 'Geschichte des Klaviers' (Leipzig 1868) ; Bie, 'History of the Piano forte and Pianoforte Players' (London 1899) ; Bluethner and Gretschel,