MECHANICS AND USEFUL ARTS. 107 



torn A wooden sound post passes from the bottom to the sounding board, 

 so that the slightest vibration on either sensitive surface is instantly commu- 

 nicated to the other. 



One other point, and the two modes of manufacture are contrasted. 



To produce a clear, pure tone a tone which will remain clear and pure 

 when forced with the utmost power, there should be no impediment to dis- 

 turb the direct vibration of the strings. In the general system of manufacture, 

 when the string reaches the bridge, its straight line is diverted by two pins 

 which receive it to the right of one, and to the left of the other, thus forming 

 a zig-zag, which was thought to be necessary to keep the string in its place, 

 and prevent rattling at the bridge. This produces what is called a side 

 bearing ; that is, the direct up-and-down vibration is stopped at the bridge, a 

 side motion given, and the struggle of the two motions resulting eventually 

 in a disturbed rotary vibration, which is more impure the more it is enforced, 

 and producing much loud sound, but no true note. 



In Mr. Driggs's piano all this disturbing influence is obviated by means of 

 saddles placed over the bridge, and fastened at each end to the sounding 

 board. These saddles have two ridges ; the foremost one is drilled, and the 

 string passes through this, and over the other, thus preserving the tension, 

 obviating all rattle, and allowing the string a direct unbroken run from end 

 to end. The result of this invention is, that the blow of the hammer pro- 

 duces a clear, pure, and undisturbed vibration, and, no matter how hard the 

 blow received by the string, it is not possible to knock out noise ; and increased 

 power will be obtained in proportion to the blow, but it will be tone, pure 

 tone, rich, deep, and sonorous. 



In this connection, we would also notice an improvement claimed in Eng- 

 land for the construction of .the sounding board, which is described as follows : 



One of the greatest improvements in the construction of pianofortes has 

 been the efficient support of the sounding board, without impairing its powers 

 of vibration. Being a large thin piece of wood, it is peculiarly liable to be 

 acted upon by the weather ; moreover, the bridge, over which the strings are 

 strained, exercises an enormous pressure, requiring adequate resistance to 

 prevent starting. But every endeavor to support the sounding board against 

 this pressure, and to keep it flat in all weathers, has hitherto interfered with 

 its vibratory power, and injured the tone and touch of the instrument. It has 

 been reserved for Mr. Dreaper, of Liverpool, to overcome the difficulty, and to 

 discover a means of supporting and regulating every portion of the sounding 

 board, in such a manner as greatly to increase the vibratory power, and, in 

 consequence, to improve the tone throughout, and to obtain other correlative 

 advantages. He has taken out a patent for it, and we have no doubt he will 

 reap from his discovery as great benefit, pecuniarily, as he has conferred on 

 the lovers of music by his improvement of that soul of private harmony the 

 pianoforte. Like most real improvements, it is so simple as to make eveiy 

 one wonder that it should not have not been discovered before. The supports, 

 instead of being solid, as hitherto applied, are hollow, and in themselves vibra- 

 tory. Mr. Dreaper calls them "harmonic chambers" and "compensating bars," 

 which are elastic, and are so contrived as to force them against the sounding 



