12 J. LOUDON ON STANDAED OP PITCH. 



are based. Accordingly whilst with this standard, the C's of the different systems 

 agree, with the musical standard (A) the C's are different. Thus if A is SIO, the C of the 

 natural scale is 522, whilst the C of the equally tempered scale is SlY'S. These 

 considerations go to show the importance of retaining imchanged the time-honoured 

 acoustical standard. The existence of two standards is not a source of incouyeuieuce, inas- 

 much as they are used for entirely different purposes ; and so long as the designations of 

 notes by musicians and acousticians practically agree, no difficulty can arise. 



(3.) With regard to the realization of absolutely correct standards, there were insur- 

 mountable difficulties until 18*78, when Koenig solved the problem by his device of the 

 clock-fork comparator. By this contrivance an auxiliary standard of low pitch is estab- 

 lished, and the actual standard determined by the usual optical method. Thus, for the 

 musical standard, the auxiliary fork is regulated to give 145 single vibrations per second 

 at the normal temperature, and the actual standard (870) is correct when the optical test 

 for 1 : 6 is satisfied. Standards have so far been constructed on this plan for Austria and 

 Italy, and the Physical Institute, Berlin ; whilst the original French standard, which was 

 constructed under the superintendence of Lissajous, has been shown to be in error by 

 TTfths of a vibration.' In the same way the acoustical standard (512) is determined when 

 the optical test for 1 : 4 is satisfied, the auxiliary fork making 128 vibrations per second at 

 20'' C. This method of establishing a standard possesses accordingly the great merit 

 that the accuracy of the standard may be tested at any time by the aid of the auxiliary 

 comparator. 



(4.) From the foregoing facts and comments on the two standards the considerations 

 which should guide us in the selection of a musical standard will be evident. Whilst the 

 standard note should be C, as it is in the acoustical system, it should agree with that 

 which is already so largely in use by musicians and instrument makers abroad. As the 

 standard A corresponding to 870 gives a C of 517'3, the agreement may be sectired for all 

 practical purposes by selecting a C of 517 or 518. Accordingly it is proposed that the 

 musical standard be the C which corresponds to 517 or 518 single vibrations per second 

 at 20° C, whilst the acoustical standard shall remain intact. It is to be hoped that 

 Canadian musicians and physicists will take some action in this matter, and by their 

 cooperation help on a movement which is calculated to put an end to confusion in the 

 musical world, and to secure the important advantages to be derived from adopting a 

 truly universal standard of musical pitch. 



' Koenig's Quelques expériences d'acoustique, p. 190. 



