542 Count Schaffgotsch’s Acoustic Experiments. 
in size generally ; a larger quantity of gas therefore flowed out 
of the outer burner, which can only be explained by a diminu- 
tion of the stream of gas in the inner burner, that is, in the one 
surrounded by the glass tube. 
3. A burner, with an aperture of 1 millim. projecting from 
below into the D-tube, about 80 millims., yielded a gas-flame 
14 millims. in length. At 5°6 metres therefrom, the first treble 
E was sung; the flame was instantaneously extinguished. The 
same thing takes place at a distance of 7 metres, when the 
flame is only 10 millims. in height, and the first treble D sharp 
is sung. 
4. The last-mentioned flame is also extinguished by the note 
G sharp sounded close to it. Noises, such as the clapping of 
hands, pushing a chair, or shutting a book, do not produce this 
effect. 
5. A burner with an aperture of 0°5 millim., projecting from 
below 60 millims. into the D-tube, yielded a globular gas- 
flame 3 to 3°5 millims. m diameter. By gradually closing a 
stopcock, the passage of gas was more and more limited. The 
flame suddenly became much longer, but at the same time nar- 
rower, and nearly cylindrical, acquiring a bluish colour through- 
out, and from the tube a piercing second treble D was sounded ; 
this is the phenomenon of the so-called chemical harmonies, 
which has been known for eighty years. When the stopcock is 
still further closed, the tone becomes yet stronger, the flame 
longer, narrower, and nearly spindle-shaped; at last it dis- 
appears. 
An effect exactly similar to that caused by cutting off the gas, 
is produced upon the small gas-flame by a D, or the first treble 
D sung or sounded from instruments; and in this case it is to 
be observed that the flame generally becomes the more sensitive 
the smaller it is, and the further the burner projects into the 
glass tube. 
6. The flame in the D-tube was 2 or 3 millims. in length; at 
a distance of 16°3 metres (more than 51 feet) from it the first 
treble D was sounded. The flame immediately acquired the 
unusual form, and the second treble D sounded and continued 
to sound from the tube. — 
7. While the second treble D of the preceding experiment 
was sounding, the first treble D was sounded loudly close to the 
tube, when the flame became excessively elongated and then dis- 
appeared. 
8. The flame being only 1‘5 millim. in length, the first treble 
D was sounded. The flame gave out the second treble D (and 
perhaps sometimes also a higher D) only for a moment and dis- 
appeared. The flame is also affected by various Ds of an ad- 
