un -DTCiss vvina insirumems as ixesonawrs. llv 



thinner wires, and, probably owing to the high tension of the 

 former, faint sounds were more readily transmitted : thus the 

 accidental or intentional touching of the tuning-fork with the 

 rim of the mouth-piece, causing a slight clicking sound, was 

 distinctly heard through the ear-piece at a distance of 150 

 yards — and this, even although the two attachments of copper 

 wire were practically at right angles to the main wire, whereby 

 part of the sound would pass away onwards up and down the 

 line. 



6. The great delicacy of the action may be inferred from the 

 fact that fine sand strewn upon the disk of the ear-piece is 

 unaffected by conversation through lengths of about 7 yards. 

 The sensitiveness also of the mouth-piece was shown by sounds 

 not spoken into it being readily transmitted, such as coughing, 

 laughing, or remarks made by persons standing beside the in- 

 strument. Indeed, in some cases an advantage is obtained by 

 keeping back from the mouth- or ear-pieces; and the author 

 has sometimes thought an improvement was obtained by hold- 

 ing the ear-piece slightly inclined to the ear. 



In all cases the individual voice could easily be distinguished 

 though modified more or less by the structure and material of 

 the mouth- and ear-pieces. 



The mouth- and ear-pieces were usually of the same form 

 and material, and were therefore used for either speaking or 

 hearing. Some forms, however, do better as ear-pieces, others 

 as mouth-pieces. 



In conclusion, the author believes that many interesting 

 physical questions may be studied by means of these arrange- 

 ments, and that practical application may be made where com- 

 munication of this nature is required. 



XVI. On Brass Wind Instruments as Resonators. 

 By D. J. Blaikley*. 



[Plate I.] 



IN bringing before the Physical Society a few notes and 

 experiments on this subject, I would desire to say that 

 they are the result of an attempt to carry somewhat more into 

 detail than, as far as I am aware, has hitherto been done, some 

 acoustical investigations of the late Sir C. Wheatstone. A 

 most interesting paper on Wheatstone's work in this field was 

 brought before the Musical Association by Professor W. Gr. 



* Communicated by the Physical Society, having been read May 25, 



1878. 



