CROSS. — MUSICAL PITCH. 467 



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

 range ones, running from C 3 to C 4 . No. 5 is a 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 A 3 and C 4 forks. It will be seen that the 

 error is in some cases very considerable, amounting for some of the A 3 

 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. 



