Velocity of Sound, ]8§ 



the supposed case would require, be made the basis of mathe* 

 matical investigation. The great Euler, to whose sagacity we 

 owe so much, was of opinion that the motion of sound is 

 affected by its intensity. Lagrange, however, thought it easy 

 to show, from theory, that this could not be the case. But, 

 besides the particulars noticed in the present article, the cir- 

 cumstance, which I formerly mentioned, of wind exercising 

 such an absolute control over the intensity of sound, and which 

 our refined theories do not recognise, sufficiently shows how 

 little confidence is due to theory in any such matters. The 

 excess of the velocity of sound, aided by a very faint breeze, 

 while passing from Montlhery to Villejuif, on the 22d June, 

 1822, over its motion on the preceding day, rather favours the 

 opinion that wind adds more than its own motion to that of 

 sound. Further experiments are, however, wanted to decide 

 this point. 



Description of a Regulating Valve for a Gas Establishment, 



10] t Mount- Street , Grosvenor- Square, 

 Sir, August 2dth,] 828. 



The continued and increasing employment of gas, as a 

 source of artificial light, confers a value upon every means 

 which renders its distribution more convenient and economical. 

 As the consumption of gas, during the night is variable, it is 

 desirable that the pressure at the gas-station should be regu- 

 lated according to the demand. I have obtained from Mr. 

 Eastwick (the very intelligent engineer of the Bath gas works) 

 a description of a valve which enables him to adjust the flow of 

 gas into the " main," so as to ensure an economical, yet suffi- 

 cient, supply to the burners at the different periods of the night. 

 If you think it deserving a place in your Journal of Science, 

 it is much at your service : I therefore enclose it for your ap- 

 provaL 



I am, Sir, yours, truly, 



R. Addams. 

 To IF, T. Brande, Esq. 



« Sir, " Gas Works, Bath, June 1st, 1828. 



'• Agreeably with your request, I send you a drawing of 

 the index of a regulating valve, which I placed on the eight- 



