CROSS. — MUSICAL PITCH. 467 



forks referred to. With the exception of No. 5, the tonometers are long 

 range ones, running from C3 to C4. No. 5 is 11 short range tonometer 

 of 12 forks, from 512 to 544 vibrations, purchased by the Massachusetts 

 Institute of Technology, in 1882. No. 1 belonged to Mr. Levi K. Fuller 

 and was purchased by him in 1892. No. 2 was made for the Massachu- 

 setts Institute of Technology in 1882. No. 3 refers to the same tono- 

 meter. The values under (2) were obtained by comparison of the forks 

 with those of (1). The values under (3) were obtained by direct com- 

 parison with Koenig's forks, as were all the results in Table V. except 

 those under (2). No. 4 is a tonometer belonging to Harvard University, 

 and which was purchased by Professor Lovering about 1883. The forks 

 taken for comparison were A3 and C4 forks. It will be seen that the 

 error is in some cases very considerable, amounting for some of the A3 

 forks to several vibrations. 



The small tonometer forks of Koenig are usually closely in accord with 

 his large standard and tonometer forks, not often deviating from the num- 

 bers stamped upon them by as much as one tenth of a double vibration. 



In all the measurements referred to in the present paper time-intervals 

 were measured by the use of an accurate stop-watch reading to one-fifth 

 of a second. 



Rogers Laboratory of Physics, 



March, 1900. 



