SENSITIVE FLAMES. 
155 
marking that he was at an evening party in which there was a 
performance on musical instruments, and that the room was 
lighted by the so-called fish-tail gas flames. Dr. Leconte says : — 
u Soon after the music commenced, I observed that the flame of 
the burner exhibited pulsations in height which were exactly 
synchronous with the audible beats. This phenomenon was very 
striking to every one in the room, and especially so when the 
strong notes of the violoncello came in. It was exceedingly 
interesting to observe how perfectly even the trills of this 
instrument were reflected on the sheet of flame. A deaf man 
might have seen the harmony. As the evening advanced, and 
the diminished consumption of gas in the city increased the 
pressure, the phenomenon became more conspicuous. The 
jumping of the flame gradually increased, became somewhat 
irregular, and finally it began to flare continuously, emitting 
the characteristic sound indicating the escape of a greater 
amount of gas than could be properly consumed. I then as- 
certained, by experiment, that the phenomenon did not take 
place unless the discharge of gas was so regulated that the flame 
approximated to flaring. I likewise determined that the effects 
were not produced by jarring or shaking the floor and walls of 
the room by means of repeated concussions. Hence it is obvious 
that the pulsations of the flame were not owing to indirect vi- 
brations propagated through the medium of the walls of the 
room to the burning apparatus, but must have been produced 
by the direct influence of aerial sonorous pulses on the burning 
jet,” 
The paper from which this extract is taken was published in 
Silliman’s American Journal for January 1858, and in the 
Philosophical Magazine for March 1858 ; but though thus an- 
nounced nine years ago in America and England, Dr. Leconte’s 
observation does not appear to be generally known in either 
country. It will be noticed that it is the converse of mine ; 
differing from it, however, in some respects. Thus, as regards 
change of appearance and the amount of visible motion, the 
shrinking of the tall flame far exceeds the spasmodic jumping 
of the fish-tail: and further, although at first both flames 
were only affected by the prolonged action of a musical sound, 
yet subsequently the upright flame was caused to shrink at 
any noise ; whilst Dr. Leconte remarks the fish-tail flame was 
uninfluenced by noises of any kind, but always required the 
energetic and sustained vibration of a musical note. Dr. Le- 
conte, however, made the happy and important observation, 
that his flame did not jump until the pressure of the gas caused 
it to be near flaring. This, as will be seen in the sequel, is the 
key-note to the whole phenomena. 
Professor Tyndall next took up the subject, and increasing the 
