116 



Mr.W. J. Millar on the Tram 



s mission 



disks with low rims to the ends of the wire: the transmission 

 of vocal sounds was then found to be easily effected, conversa- 

 tion being readily carried on through this length of wire. 



Since that time the author has made many experiments with 

 various combinations and under various circumstances. The 

 principle upon which they all more or less appear to depend, 

 so far as the rendering audible of the sounds, is that of the 

 tuning-fork and sounding-box, in which the sound from the 

 vibratory movements of a metal body is considerably intensi- 

 fied when the body is placed upon a sonorous substance affect- 

 ing the air in its vicinity. 



3. JN~otes of some of the more important Experiments. 



(1) No. 23 copper wire was stretched between windows out- 

 side of house, and attachments at right angles made to rooms 

 through the windows. Speaking in one room was then heard 

 in the other; the distance was about 20 yards. Pianoforte 

 music was easily transmitted by placing an ear-piece inside 

 the instrument and carrying the other end of the wire outside 

 the house. 



(2) No. 40 copper wire fitted up in a building, passing 

 from room to room as per diagram below. Six attachments and 

 angles. 



\ 



\ 











\ 



\ 



Hull. 





























I 



\ 



33 ~^v 



Room. . 





Pass.upe, 







