The transposing device, in turn, is now becoming popular on player pianos, which are being increasingly used for accompaniment purposes. It is obviously a great advantage to be able to suit the requirements of any particular voice in this way and the means of doing so are easily provided. In the ordinary instrument on the other hand it is difficult to keep transposing devices in perfect order owing to the necessity for shifting the keys relative to the action, a movement which upsets the delicate regula tion of the repetition, and renders the device unsatisfactory.
Finally, the double keyboard, as invented by Emanuel Mo6r, represents a really important de velopment, extending the re sources of both performer and composer to an astonishing de gree. Such a revolutionary de parture will doubtless take time to become commercially possible, but the most weighty musical opinion is entirely in its favour. Briefly stated, the second key board lies just behind and above the normal standard notes, and operates those strings which are an octave higher. Consequently it is possible to play extended chords, arpeggios and double octaves with great facility. There is also an octave coupler which further increases the possibilities of the instrument from the point of view of volume. To what extent the principle will ever secure general adoption it would be rash to prophesy, but as to its ingenuity and musical value there is no room for doubt.
The principles discovered in the early actions (Erard 1821 and Robert Wornum 1826) still stand firm, and all subsequent im provements have been built thereon. The separate parts of the modern action are produced by automatic machinery, and as sembled by hand with great skill and accuracy. The pianoforte manufacturer has long recognized the advisability of allowing this important component to be made for him by specialists, the hammers and hammer shanks being fitted after the action has been installed.
Present-day development is towards a greater tonal volume without altering the weight or depth of touch, any increase in which is a serious handicap to the virtuoso. The sound-board is made as sensitive as possible, supported in a rigid frame-work which absorbs little or no energy from the board at its edges.
The modem souhd-board sus tains a continual down-pressure from the strings of nearly half a ton, whereas the early grand pianos had scarcely a hundred weight pressure thereon. The string tension has tripled (from 6o to i8o lb. per string in some instances) with the ability of the wire drawers to supply stronger and stronger wire, and the iron founder has had to devise cast ings which stand a total stress of 16 tons and upwards without occupying too much room, or covering too large a portion of the surface of the sound-board. Some early makers had the mis taken idea that an iron structure entailed the production of a "metallic" tone in the instrument ; but those who adhered to the use of the wooden frame were soon left behind, mainly owing to the extreme susceptibility of the pitch of such pianos to tempera ture and humidity changes, which rendered the tuning very unstable.
As regards the future, one of the most interesting of the possi ble further developments which have been mooted is the electrical agitation of the strings so as to secure a sustained tone instead of one which rapidly diminishes after the moment of impact. In Germany experiments are being made with quarter-tone scales, which may or may not develop a new technique for composers and performers, but the standard key-board of to-day has such a wide range of frequencies (from 27 to 4,176 vibrations per second) that it is unlikely that it will be superseded for many years to come. (A. J. H.; K. S.; S. A. H.)