THE MODERN PIANO-FORTE. 695 



not have been fully realized. The softer tissues still remained of 

 wood of various kinds, and other such essential materials. With the 

 acquisition of an iron frame or vertebra equal to the tensile strain of 

 thirty tons without danger of fractures, came the temptation to em- 

 ploy strings of greater thickness, with a tension of from eleven to six- 

 teen tons. These sti'ings, stretched as near as possible to the limit of 

 elasticity, that they might give forth the most vigorous vibrations, 

 required to be set in motion by blows from hammers specially adapted 

 for the purpose. (Voices similarly strained on the liighest notes 

 within their compass also have the most brilliant quality, as for in- 

 stance the "G" of Mr. Santley and the chest "C" of Tamberlik.) 

 Then, again, the increased powers of the instrument made greater de- 

 mands on the sound-board. 



If we compare the vibrations of the violin, set up by the com- 

 paratively gentle friction of the bow, with those of a piano-forte 

 sound-board, violently trembling in response to strong percussive 

 accents, and the multitudinous and continuous vibrations of long, 

 thick metallic strings, it is at once evident that they are of a more 

 extraordinary nature. Great discrimination was used in the selec- 

 tion of the wood from the spruce-trees of the Northern forests ; many 

 experiments were made to discover which way the grain of the wood 

 should be disposed, and. in what manner the sound-board should be 

 compelled to receive and transmit impressions without fear of such 

 derangements as should lead to a state of paralysis. To make it act 

 most energetically the fibres were permanently compressed longitu- 

 dinally, as in a vise, up to a certain point, similar to the strings, which, 

 as we have just now seen, give forth tones of most satisfactory quality 

 when stretched to the verge of breaking. There is a readily-found 

 precise limit to this compression, after which the tones become hard 

 and thin in quality. The sound-board is now also slightly curved, 

 forced upward or made convex that it may resist tlie downward press- 

 ure of the bridge that holds the strings slightly elevated from their 

 level, to secure a complete and intimate communion for the transmis- 

 sion of vibrations. It is clear that, if, from any cause, a sound-board 

 should become concave, or loose at any of the sides, serious conse- 

 quences would ensue. Considerations such as these sufficiently prove 

 that the attainment of a perfect harmony among the parts, to resist 

 successfully external influences, was no slight undertaking. 



The American piano-forte has, however, attained a constitution 

 that will endure dryness, cold, and even furnace-heat, but succumbs 

 to excessive dampness. A good instrument, dried to the utmost, 

 rapidly absorbs moisture. The well-fitted parts, having no room to 

 swell, then become rigidly bound together, and thus the action is de- 

 stroyed. It would therefore suffer if placed in a room having no sub- 

 cellai', under which water-courses might be formed after rains. An 

 inferior instrument made with damp materials and kept damp by 



