Polytechnic Association. 713 



room, we could not discover that the distance of the sound had any 

 effect upon the result. 



Dr. J. W. Richards — The statement that the vowel O did not 

 affect the flame coincides with the statement of Prof. Thurston that 

 sharp sounds do affect it. 



Dr. P. H. Van der Weyde — I experimented on the subject ten 

 years ago, and took out a patent for a gas alarm on the same principle, 

 but it would not always act, and its unreliability made it useless. 

 Take an Argand burner, and put it over a disc of* wire gauze, and it 

 will have the effects of a Bunsen burner. Put over that a tube of 

 the proper length, and you will get a sound. With a stove-pipe it 

 will roar like a lion. Above this was a very small flame always burn- 

 ing, so as to light the other when the gas was turned on by opening 

 a door or window. In Philadelphia, we made an organ on the same 

 principle, taking pipes of different sizes. Unfortunately, as the pipe 

 was heated the pitch kept rising, and the discord was horrible. 



The President — This invention of Mr. Barry's is only a modifica- 

 tion of that of Dr. Yan der Weyde. 



VI. Sounds from the Aurora. 



At a recent meeting of the French Academy of Sciences, Becquirel 

 expressed the opinion that the aurora does produce sound, and in 

 confirmation of this view cites the observation of Paul Rollier, aero- 

 naut, who started from Paris, in December last, and descended 

 fourteen hours after in Norway, on Mount Ida, at an elevation of 

 4,000 feet. " I saw, through a thin fog, the moving of the brilliant 

 rays of an aurora borealis, spreading all around its strange light. 

 Soon after, an incomprehensible and loud roaring was heard, which, 

 when it ceased completely was followed by a strong smell of sulphur, 

 almost suffocating." Professor Loomis and other meteorologists have 

 seen no satisfactory evidence that the aurora ever emits any audible 

 sound, believing that the noises ascribed to the aurora are due to 

 other causes such as the wind, or to that low temperature of snow 

 and ice which sometimes produces sudden movement. 



Dr. Van der Weyde — The aurora acts upon the needle like an 

 electric current, and must be electric. It cannot be the reflection of 

 the sun's light, for we find the solar lines in everything the sun shines 

 on ; but the aurora, when we turn the spectroscope upon it, does not 

 give us the solar lines, but those of the corona. If the aurora is elec- 

 tric, it is probable that tliere will be sound. 



Dr. Feuchtwanger — In cold climates, electricity is more developed 



