I 
1895-96.] Prof. M‘Kendrick on a Sensitive Flame. 45 
Note on a Sensitive Flame. By John G. M ‘Kendrick, 
M.D., Professor of Physiology in the University of Glasgow. 
(Read February 17, 1896.) 
Dr M‘Kendrick showed an extremely sensitive flame made by 
Dr R. Koenig. It is constructed on the type of the sensitive 
flame apparatus devised by Barrett* and improved by Govi. 
A Lecomte f burner directs the gas towards a fine wire gauze screen, 
and when the gas is lit above the screen the flame is very sensitive 
at ordinary pressures. The special part of the apparatus now 
shown consisted of a funnel or resonator placed at right angles to 
the Lecomte gas-jet and opening into the space below the gauze 
screen. To ensure success a fine stop-cock or clip must be used for 
the regulation of the quantity of gas. Dr M ‘Kendrick showed 
also that by placing a glass tube 460 mm. in length by 40 mm. 
in diameter over the flame, and about 4 mm. above the level of 
the gauze, as first suggested by Geyer,| a musical note was heard 
which was disturbed by vibrations acting on the flame. The 
apparatus not only showed the ticking of a watch, placed in the 
resonator, by the movements of the flame, but with each “ tic ” the 
tube sounded slightly. The slightest movement in the vicinity 
of the apparatus agitated the flame ; and as the latter was arranged 
so as to be near the point when it evoked the tone of the tube, now 
and again the tube gave forth a strong tone as a vibration acted 
on the mass of gas below the gauze. 
* Barrett, Phil. Mag., 1867. 
t Lecomte, Phil. Mag., 1856. 
J Described at p. 65 of Sound, by Alfred M. Mayer. London, 1879. 
