A method of fastening the strings on the string-plate de pending upon friction, and thus dispensing with "eyes," was a contribution of the Collards, who had retained James Stewart, a man of considerable inventive power, who had been in America with Chickering. This invention was introduced in 1827. Be tween 1847 and 1849 Mr. Henry Fowler Broadwood, grandson of John Broadwood, invented a grand pianoforte to depend practically upon iron, in which, to avoid the conspicuous inequalities caused by the breaking of the scale with resistance bars, there should be no bar parallel to the strings except a bass bar, while another flanged resistance bar, as an entirely novel feature, crossed over the strings from the bass corner of the wrest-plank to a point upon the string-plate where the greatest accumulation of tension strain was found. After the Great Exhibition of 1851 he employed an ordinary straight bar in the middle of his concert grand scale, his smaller grands having frequently two such as well as the long bass bar. After 1862 he covered his wrest-plank with a thick plate of iron into which the tuning pins screw as well as into the wood beneath, thus avoiding the crushing of the wood by the constant pressure of the pin across the pull of the string.
The introduction of iron into pianoforte structure was differ ently and independently effected in America, the fundamental idea there being to use a single casting for the metal plate and bars, instead of forging or casting them in separate pieces. Alphaeus Babcock was the pioneer of this kind of metal construction. He also cast an iron ring for a square piano in 1825, which, although not a success, gave the clue to a single casting resistance framing, successfully accomplished by Conrad Meyer, in Philadelphia, in 1833, in a square piano which still exists, and was shown in the Paris Exhibition of 1878. Meyer's idea was improved upon by Jonas Chickering (1797-1853) of Boston, who applied it to the grand piano as well as to the square, since which time this prin ciple has been universally adopted.
We have now to consider over- or cross-stringing, by which the bass division of the strings is made to cross over the tenor part of the scale—the object being in the first instance to get longer bass strings than are attainable in a parallel scale, and in the next to open out the scale and extend the area of bridge pressure on the sound-board. In the i8th century clavichords were sometimes overstrung in the lowest octave to get a clearer tone in that very indistinct part of the instrument (strings tuned an octave higher being employed). The first sug gestion for the overstringing in the piano was made by the cele brated flute-player and inventor Theobald Boehm, who carried it beyond theory in London, in 1831, by employing a small firm located in Cheapside, Gerock & Wolf, to make some overstrung pianos for him. Boehm expected to gain in tone ; Pape, an ingen ious mechanician in Paris, tried a like experiment to gain econo my in dimensions, his notion be ing to supply the best piano possible with the least outlay of means. Tomkinson in London continued Pape's model, but neither Boehm's nor Pape's took permanent root. The Great Exhi
bition of 1851 contained a grand piano, made by Lichtenthal of St.
Petersburg, overstrung in order to gain symmetry by two angle sides to the case. It was regarded as a curiosity only. Later, in 1855, Henry Engelhard Steinway (originally Steinweg; 1871), who had emigrated from Brunswick to New York in 1849, and had established the firm of Steinway & Sons in 1853 in that city, effected the combination of an overstrung scale with the American iron frame, which exhibited in grand and square in struments shown in London in the International Exhibition of 1862, excited the attention of European pianoforte makers, leading to important results.
It would be inaccurate to say that no outstanding developments have taken place in pianoforte construction during the last fifty years, but few new principles have been discovered, and im provement has taken place almost entirely in the direction of apply ing in greater and greater meas ure scientific knowledge to meth ods and practices previously empirical (see PIANOFORTE MAN UFACTURE) thus resulting in im provement in tonal volume and purity.
Summing up matters it may be said that the modern pianoforte retains six important characteristics of the clavichord, in that it has an independent sound-board (i.e., the ends of the strings are not fastened to it), dampers to prevent vibration of the strings not in use, "listing" cloth to deaden the vibration from the ends of the strings beyond the bridges, groups of three strings tuned in unison and a tone production which depends upon a blow instead of a plucking (as in the spinet and harpsichord).
Five of the ideas developed in the harpsichord have also sur vived or have been revived from time to time, namely, the sus taining pedal, the celeste felt for soft playing, the transposing key board, the soft stop for practising very quietly, and the double manual (viz., as recently introduced by Emanuel Moor).
As regards the sustaining pedal the importance of this cannot be over-estimated, for not only does it allow of harmonies being maintained when necessary without holding the keys down, but it also modifies the tone quality by allowing all strings to take part simultaneously by means of their resonance. Moreover the sound board is encouraged to increase its ampli tude of vibration, thus increasing the tonal volume, which in skilful hands can be made to reach a maximum intensity of over twenty times that of the most pow erful harpsichord. Contrariwise, the tone can be attenuated and diminished by means of the soft pedal, which brings the hammers nearer the strings, or (as in the case of grand pianos) shifts the hammers so that they strike two instead of three strings. The "celeste" pedal and "soft stop" devices both involve the introduc tion of a strip of felt between the strings and the hammers at the point of contact, thus reducing the force of the blow. For school pianos, used for practising almost continuously throughout the day, the soft stop is a most useful adjunct and when properly designed need not interfere un duly with the touch of the instrument.