PEA OMENTS OF SCIENCE. 



and removing the sensitive flame to/', some distance be- 

 hind the reed, it burned there tranquilly, though the reed 

 was sounding. Again lighting the gas as it issued from 

 the brass tubes, the sound reflected from the heterogeneous 



FIG. 9. 



air threw the sensitive flame into violent agitation. Here 

 we had imitated the aerial echoes heard when standing 

 behind the syren-trumpet at the South Foreland. The 

 experiment is extremely simple, and in the highest degree 

 impressive. 



The explosive rapidity of dynamite marks it as a sub- 

 stance specially suitable for the production of sound. At 

 the suggestion of Professor Dewar, Mr. McRoberts has 

 carried out a series of experiments on dynamite, with 

 extremely promising results. Immediately after the 

 delivery of the foregoing lecture I was informed that Mr. 

 Brock proposed the employment of dynamite in the 

 Collinson rocket, 



