164 



ANNUAL OF SCIENTIFIC DISCOVERY. 



The precision with which the laws of vibration may be verifiocl 

 bv the use ot" this instrnment is in the hiirhestdej^ree satisfactory. 

 However numerous the repetitions (jf au exj^eriuient may be, the 

 registry varies only Ijy a siugle dot. Moreover, it makes the law 

 rest upon no comparison of sounds produced by the vibrations, 

 nor upon any other eflect of the motion, but upon the vibrations 

 themselves, whose numerical relations are directly shown. Vi- 

 brations, sonorous or otherwise, are thus equally the subject of ex- 

 perimental investigation. 



Prof. Cooley gives this table of vibrations, which differs from all 

 others relating to music; first, in being the result of a direct res- 

 ist nj ; and, second, in that it shows all tlie intervals of the scale. 

 Tile piano upon which the registry is based was tuned to the 

 standard pitch of the Boston Music Hall oi'gau. 



Tlie octave above A= 208.5 is the la usually referred to in de- 

 scribing the pitch of the orchestra; it is thus produced by 417 com- 

 plete vibrations i^er second. 



In the time of Louis XIV., the pitch of this A was, according 

 to Sauveur, 405 vibrations per second, while b}' the action of the 

 congress called together by the Society of Art^, at London, in ISOO, 

 it was 440. The same note sounded by Handel's tuning-fork 

 (1740) is said to have been made by 41G vibrations per second. It 

 will be thus seen that while the present jntch is nearly one-half of a 

 tone higher than that referred to by Sauveur, and considerably 

 more than that interval lower than that of the London Congress, 

 it agrees with the pitch adopted l)y Handel, to within a single 

 vibration. — Prof. Cooley, -Journal Fran/din Institute. 



CONDUCTING POWERS OF MATERIALS. 



According to the experiments of Mr. AI. G. Farmer, made some 

 years since, the relative electrical resistance of ditferent metals 



