S% INFLUEN^CE ©r LICHtOK THE PPvOrAGATIOW OrSOl-ND.-- 



feet. feet Eng.* 



In atmospheric air ..mi.. 59 •••• 98'8B 



carbonic acid gas 48-4 ••• • 8l'll 



oxigen gas 66*5 . • • • 11 1*45 



nitrogen gaa • • • » the same 



hidrogen gas 13 .... 21*79 



Oxigen best The results of this experiment seem to prove, that of the 



&dai)ted to its (Jiflfgreiit gaseous substances oxigen is best adapted for trans- 

 trausmisbion. ..*?.,. ,. , t i , ,• 



mitting the vibrations ot sonorous bodies; and the equanty 



of eftect obtained with nitrous gas, which contains 0*56 of 

 oxigen, gives reason to think, that the increase of the pro- 

 pagation of sound has a determinate measure, and that a 

 given quantity of oxigen gas diffused in the atmosphere is 

 sufticient, to carry it to its uiaximumf. 

 Isthi^the This reasoning appears to me the more satisfactory, as it 



cause of the connect the results obtained by Mr. Perolle with those 



effect of day- -^ . . , , • - , , 



liglu? of my experiments. It is certain, that during the day, and 



under the influence of the light, the atmospheric air is more 

 saturated with oxigen than during the night ; but it remain^ 

 to be proved whether this surplus of oxigen, which from 

 the nicest eudiometrical researches cannot exceed a few hun- 

 dredths, can be capable of producing such a remarkable 

 change. 

 Or rather, is it ^^ the other hand, when it is proved, that the density of 

 not lij^ht that gasses is not the only reason of the acceleration of the pro- 

 'l^i'd ni'tryus '^'^ K^^^^ of sound ; and my experiments appear to demonstrate 

 gisi a certain influence in light; may we not consider the latter 



as the true cause of the increased propagation of sound in 

 oxigen and nitrous gas; since we know, that oxigen has a 

 great capacity for light, aiul that nitrous gas cannot be form-* 

 ed without the concurrence of this substance? Whatever 

 may be the opinion of natural philosophers on this subject, 

 it is certain, that the hypothesis reconciles my experiments 



♦ I suppose the feet in the preceding column to be those of Turin. C. 



Light has con- | q-^e illustrious Dr. Bonvcisin, wlio, in bis Elements of Chemistry, 



tn crenTicd'^'^ '^^^ ^^*^^^ ^""^^^ opportunity of pointing out to his pupils the influence, 



... \ji. that light exerts on u number of chon-.ical actions, particularly notices 



the necessity of the concurrence of light in all the combinations of ni- 



rrft^.-^u -nith o.-^ig'-n. See vol. l,art. Acide, nilrique. 



witk 



