'ISO Intelligence and Miscellaneous Articles. 



'to 



Presents, curious specimens, and new machinery were laid upon 

 the library tables as usual. 



Feb. 15. — The subject of the evening was Resonance, or the reci- 

 procation of musical sounds. It was explained and illustrated by 

 Mr. Faraday ; but he stated that his information was obtained from 

 Mr. Wheatstone, to whom belonged also the new matter brought 

 forward. 



The vibration of one string when another in unison with it was 

 struck, was referred to as an illustration of the nature of reciproca- 

 tion. The honour of this discovery was given to Messrs. Noble and 

 Pigott, pupils of Dr. Wallace. Reciprocation by undulations com- 

 municated through the air, or through solid bodies, was then illus- 

 trated, and the nature of stringed instruments explained. 



After this, followed matter of a more original nature. It was stated 

 that columns of air could reciprocate to vibrating bodies, when their 

 vibrations could accord with those of the latter j in illustration of 

 which, a flute was made to speak, simply by approaching a vibrating 

 tuning-fork to its embouchoir. Other columns of air were also made 

 to produce intense sound by reciprocating with tuning-forks which 

 were themselves inaudible. An elementary model of an instrument 

 to be constructed upon this principle was also exhibited. 



Some musical instruments were then referred to, which had been 

 brought by Sir Stamford Raffles from Java, and which had been lent 

 to the Institution by Lady Raffles, for the evening's illustrations. 

 They consisted of plates of sonorous metal, suspended by their nodal 

 points over pipes of bamboo adjusted to reciprocate to the lowest 

 note produced when the plate was struck. When the apertures of 

 the tubes were covered, and the plates made to sound, the ordinary 

 tones were produced j but upon removing the cover, the air in the 

 tubes instantly reciprocated to the lower notes, and a series of fine 

 rich sounds were produced. This instrument is called the Gender. 



A further illustration of the reciprocation of sound was then given 

 on the guimbardor Jews-harp, the different tones of which are found 

 to depend upon the circumstance, that columns of air reciprocate not 

 only when they vibrate in equal times with the original phonic, but also 

 when their vibrations are any multiple of those of the phonic. This 

 fact was illustrated by a syringa, and also by the beautiful perfor- 

 mance of M. Eulenstein on the Jews-harp. 



Some illustrations of the resonance of the columns of air in the 

 cavities of the ear were then given, — and the subject concluded. 



In the library were several beautiful engravings, by Robinson, 

 Turrell, and others.- A new perspective instrument by Mr. Turrell, 

 called a Perspectograph, &c. Sec. 



XXXVIII. Intelligence and Miscellaneous Articles. 



ANALYSIS OF SOME ALLOYS OF BISMUTH. 



MLaugier has analysed several of these compounds. To analyse 

 • an alloy of bismuth and lead, he dissolves it completely in dilute 

 nitric acid, and then pours into the solution'one of carbonate of am- 

 monia, 



