Mr. A. J. Hipkins. On the Harmonics of a String. 363 



November 20, 1884. 

 MR. J. EVANS, Yice- President and Treasurer, in the Chair. 



In pursuance of the Statutes, notice of the ensuing Anniversary 

 Meeting was given from the Chair. 



Professor Walter Noel Hartley and Professor Wilfrid H. Hudleston 

 were admitted into the Society. 



Mr. J. Ball, General Boileau, Sir James Cockle, Dr. Rae, and 

 Mr. G. J. Symons, having been nominated by the Chairman, were by 

 ballot elected Auditors of the Treasurer's Accounts on the part of the 

 Society. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : 



I. " Observations on the Harmonics of a String struck at 

 one-eighth of its Length." By ALFRED JAMES HIPKINS 

 (of John Broadwood and Sons). Communicated by 

 ALEXANDER J. ELLIS, F.R.S. Received October 1, 1884. 



The string observed was a steel pianoforte wire, gauge number 

 19^, diameter 1'17 mm. = '07 inch, of exactly 45 inches vibrating 

 length, stretched by a tension of 71 kilogrammes = 156'63 Ibs., and 

 forming the note C of 135 - 2 vibrations, in the second space of the bass 

 staff, in one of Broad wood's concert grand pianofortes accurately 

 adjusted to be struck by the hammer at one-eighth the length of the 

 string from the wrestplank end, or 39'375 inches from the belly- 

 bridge. Actually three such strings, forming the usual trichord of 

 a grand pianoforte accurately tuned in unison, were used to augment 

 the volume of tone. The positions of all the nodes less than 

 t)9 - 4 inches from the belly-bridge for the first 20 harmonics, were 

 previously calculated. All three strings were stopped at the same 

 distance from the belly-bridge with the edge of a piece of felt glued 

 to a piece of wood by Mr. Hartan, the foreman of the tuners, while 

 I struck the note. A considerable weight and steadiness of blow 

 was necessary to excite the harmonic. The sound at first was dull 



VOL. xxxvn. 2 B 



