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Scientific American Supplement, No. 385, May 19, 1883 by Various
page 64 of 130 (49%)
was, in a great measure, thrown upon the tubes. The tubes were a
mistake; they were of iron over the steel strings, and brass over the
brass and spun strings, the idea being that of the compensation of
tuning when affected by atmospheric change, also a mistake. However,
the tubes were guaranteed by stout wooden bars crossing them at right
angles. At once a great advance was made in the possibility of using
heavier strings, and the great merit of the invention was everywhere
recognized.

James Broadwood was one of the first to see the importance of the
invention, if it were transformed into a stable principle. He had tried
iron tension bars in past years, but without success. It was now due to
his firm to introduce a fixed stringed plate, instead of plates intended
to shift, and in a few years to combine this plate with four solid
tension bars, for which combination he, in 1827, took out a patent,
claiming as the motive for the patent the string-plate; the manner of
fixing the hitch-pins upon it, the fourth tension bar, which crossed the
instrument about the middle of the scale, and the fastening of that bar
to the wooden brace below, now abutting against the belly-rail, the
attachment being effected by a bolt passing through a hole cut in the
sound-board.

This construction of grand pianoforte soon became generally adopted in
England and France. Messrs. Erard, who appear to have had their own
adaptation of tension bars, introduced the harmonic bar in 1838. This,
a short bar of gun metal, was placed upon the wrest-plank immediately
above the bearings of the treble, and consolidated the plank by screws
tapped into it of alternate pressure and drawing power. In the original
invention a third screw pressed upon the bridge. By this bar a very
light, ringing treble tone was gained. This was followed by a long
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