484 Scientific Intelligence. 
other capsule with the lowest, and by means of the other two 
pipes I connected both capsules with the middle burner. If I now 
2. 
sound the tuning forks, both branches being of equal length, os 
three flames in the revolving mirror appear as three sert 
flames cloven to an equal depth one above the other. On ‘engi 
ening one branch half a wave-length of the note, the middle one 
alone becomes a simple band of light, while the other two com 
tinue to vibrate with uncha i intensity. Here we observe at 
the same time the effect produced by waves of sound coming 
through each arm separately and oahen they are reunited. 
a. in these experiments we use an open organ pipe, instead of a 
uning fork with resonator, the vibrations of the octave appear 
aids during the interference “sl oe waves of the > fandamental 
note; provided the organ pipe is not of too great diameter. In 
the same manner as the feb hte note we can also remove any 
24 sgn rd a note by means of interference. This can be shown 
very ni by means of a closed pipe. I introduce its sound 
into the ata by connecting it to the latter by means 0 
m tube attached to its termin are capsule, after removing 
the gas burner. If I then pull out the tube so far that im 
terference is produced for the ate 3, the middle. flame in the 
