118 



now before us, include all these lunar variations during more than 

 the Metonic period of 6940 days. 



Mr. Luke Howard says in his summary — " It is to be inferred 

 from these, that the barometrical mean is depressed by the moon's 

 position in south declination — the depression is gradual — but upon 

 the planet quitting her south position to return north, an elevation in- 

 dicates a return of the pressure to its former position." 



Prof. Frazer described an attempt which had been made by- 

 Prof. J. C. Cresson and himself, to repeat Biot's celebrated 

 experiments upon the transmission of sound through iron 

 pipes. 



The pipe upon which they experimented was a gas main just laid 

 in South street, from Broad to Ashton, and up Ashton, from South to 

 Lombard. It was 4300 feet long and 8 inches in diameter, and had 

 one turn, at right angles, at the corner of South and Ashton. This 

 turn was made by a piece of pipe with four branches — two of which 

 (the south and west) were plugged— the other two making the com- 

 munication. 



As the pipe was laid in the ground, with a mass of moist earth 

 lying upon it, it was, perhaps, not to be expected that the vibrations 

 excited in the iron would be propagated to any great distance, but 

 the experimenters found, to their surprise, that even the heavy blows 

 of the sledge upon the inner part of the pipe were not communicated 

 through the air. They had provided themselves with hammers and 

 bells for the purpose of making the signals, but in consequence of 

 the very strong language used by M. Biot in describing his experi- 

 ments, they had not taken the precaution to provide pistols for ex- 

 plosions. It appears, that in the French experiments there were two 

 bends in the pipe, but at what angle is not mentioned in any account 

 which we have been able to obtain, (as it appears that the Memoires 

 de la Societe d'Arceuil, in which the original account of the experi- 

 ments is contained, is not in any library in this city). 



As it was necessary to connect the pipe under experiment with the 

 other mains without delay, it was not possible to pursue the experi- 

 ments any farther, but Profs. C. and F. hope to have, during the ap- 

 proaching summer, an opportunity of repeating them upon another 

 pipe, and under more favourable circumstances, so as to detect, if 

 possible, the cause of their present failure. 



The annual report of the Publication Committee was pre- 

 sented by Mr. Lea. 



