Page:Popular Science Monthly Volume 11.djvu/718

698 Cheaply-made piano-fortes are mostly sold to ignorant persons, living far from the great centres of civilization.

It will be found interesting to notice some of the facts learned by those who have conducted experiments in the hope of improving the piano-forte, for many of these are somewhat peculiar, and contrary to general anticipation. Thus: Chladni's figures are not formed by sand strewed on the sounding-board; nor does the sand travel from the point where the shocks or impulses are imparted to this vibrating body, but collects at this very point, namely, close to the bridge. Again, no difficulty is experienced by "interference," when two or three strings tuned in perfect unison vibrate side by side; nor from overstringing the bass wires. The fitting together of trough and crest of sound-waves—the coincidence of the "swing" and the "swang," which cancels both, and forms the hyperbolic curve of silence on the outer broad side of each prong of a tuning-fork, is a phenomenon that does not appear in any portion of the scale. Nor does that which is termed "sympathy," that occurs when two organ-pipes stand too near each other, require consideration from the designer of a piano-forte. The addition of a second string, far from destroying the vibrations of the first, or even interfering with them, more than doubles the power of the tone. A single string gives forth a comparatively insignificant and feeble note. When three strings are used, the third does not add half as much again, a fourth string adds still less in proportion, and, judging from the quality of the tone produced, seems to require an entirely new design.

In the final adjustments of the piano-forte by men of extremely keen sensibilities, certain defects, limitations, and peculiarities of the human ear, have been discovered that are noteworthy. The Greek architects well knew that long horizontal lines, if straight, would not appear to be straight when viewed from below, and therefore in the Parthenon they executed exceedingly delicate curves. Their columns were not exactly cylindrical, and many similar and most subtile deviations from geometrical truth were employed that remain as evidences of their consummate skill. In music, also, certain nuances—deviations from rigid accuracy or mathematical truth—are constantly made by which the powers of true artists are manifested. These minute shades of difference—these slight variations or modifications of quality of tone, power of tone, pitch, speed, etc.—when not exaggerated, but determined with an art-concealing art, are found to be true to Nature, and find their justification, not as exceptions to general rules, but as exemplifications of the highest principles. The refined perceptions of piano-forte finishers have led them to the fact that the highest notes of the instrument should be tuned slightly sharper than perfect, or each note will appear to be flat, when compared with the octave below. If these notes are tuned perfectly, and proved to be so by various tests, there still remain a secret dissatisfaction and