26 M. Dvorék—Acoustic Repulsion. 
passes from the node to the ventines at least in Kundt’s tube, in 
which the air waves are very powerful. This principal current 
lasts as long as the air vibrates. Sonic the same experiments 
show a continuous secondary current, close to the walls of the 
tube and in a direction contrary to that of the principal current, 
so that the whole air in the tube is in circulation. The cross 
section of the principal current is nearly as great as that of the 
tube, while that of the secondary current is a very narrow ring. 
The excess of pressure as shown by a manometer at the 
node is always less than the chisobetionl pals because in the 
latter the air is not supposed to move from the node and to 
equalize the pressure. Of course the excess of pressure at the 
ventre is not equal to zero, as theory requires. Probably the 
tube, is probably neutralized by a ottiats. and contrary ie 
"The exit of the air can easily be proved, as follows: a spher- 
ical glass resonator is placed before the resonant base of a tun- 
ing fork, the resonator is filled with tobacco smoke, strong 
vibrations are given to the fork, eheb the smoke will be seen 
to rush pom the resonator. 
I have succeeded in ard chazersticsly strong currents 
of air in still another va ae I ety not yet “found an 
explanation of these complicated 
A cone made of stiff paper was aid wi with i its large end oppo- 
site the opening of a rads napa tube. The size of this cone 
may vary, but its effect is greatest when it vibrates to the 
same note as the Kundt’ s tabe, ned so forms a resonator ope 
