190 



SCIENTIFIC AMUSEMENTS. 



in blasting for mining and quarrying, &c., the sudden pressure 

 rends and tears the rock asunder, a result which sometimes 

 happens to a gun if the metal is not strong enough to resist the 

 force and prevent its bursting. 



Expt. 209. To produce Musical Sounds by means of a 



Hydrogen Flame. Arrange a 

 hydrogen generator with an upright 

 jet so as to burn the gas experi- 

 mented with, as in fig. 81. Hold 

 over the flame and surrounding it 

 like a lamp chimney a glass tube 

 half an inch internal diameter and 

 a foot long ; if the size of the flame 

 is properly proportioned, the flame 

 will be thrown into a state of 

 vibration by the current of hot air 

 and steam passing up the tube, so 

 that the hydrogen issues from the 

 jet in a series of pulsations, instead 

 of a perfectly uniform stream. 

 The effect of this is that the 

 column of air in the glass tube is 

 thrown into vibration too, like 

 that in an organ pipe, and a musical 

 sound produced, the tone of which 

 depends on the length and dia- 

 meter of the tube used, being 

 generally the shriller the shorter 

 the tube. A musical instrument, 

 called the hydrogen harmonicon, has been constructed on this 

 principle, furnished with a keyboard like a piano, so arranged 

 that when a key is pressed down a current of hydrogen is 

 turned on to a jet in a suitable pipe, and at the same time is 

 lighted by means of an electric spark, so as to develop sound ; a 

 separate jet and properly tuned pipe is of course required for each 

 note. As yet, however, this instrument has not found its way 

 into musical orchestras, the reason for which will doubtless be 

 appreciated by the experimenter whilst trying different sizes of 

 tube, some of which are pretty sure to produce most doleful wails 

 and squeaks, reminding one of the effect of a "cat concert," where 

 each performer takes a cat in his or her arms, eliciting a note by 

 judiciously pinching the tail gently, or otherwise coaxing pussy to 

 emit a yell or a growl as the case may be. Fig. 82 represents a 

 series of four tubes, any of which can be used simultaneously, 



Fig. 81. Singing Tube. 



