46 BULLETIN OF THE 



their intensity has been extinguished, we may find iu this fact an 

 explanation of the statement made by Reynolds, that " on all oc- 

 casions the effect of wind seems to be rather against distance than 

 distinctness." * 



10. As sounds may be inaudible at certain distances and eleva- 

 tions without being wholly extinguished, it follows that the com- 

 parative inaudibility of sounds at different times cannot always be 

 cited as an evidence of their relative intensities. The comparative 

 inaudibility may be a function of variable refraction rather than of 

 variable intensity. Hence the law of inverse squares, though per- 

 fectly true in its theoretical application to the measurement of the 

 intensity of all sounds, cannot always be legitimately used to cal- 

 culate backwards from the audibility of a sound, as empirically 

 ascertained at a given point and elevation, to its relative intensity 

 as previously heard at the same point and elevation. 



11. The hypothesis of Stokes, as applied by Henry, does not 

 exclude the hypothesis of Humboldt, but reduces the latter to a 

 very subordinate and inappreciable place in interpreting the ab- 

 normal phenomena of sound. 



12. The hypothesis of Stokes, as applied by Henry, does not ex- 

 clude the reasoning or the experimental proofs by which Prof. Rey- 

 nolds demonstrates that differences in temperature exert a refracting 

 power in sound, but finds in that refraction an influence which may 

 sometimes accelerate and sometimes retard the refraction produced 

 by wind.f 



The next communication was by Mr. C. H. Koyl, Fellow of the 

 Johns Hopkins University, on 



THE STORAGE OF ELECTRIC ENERGY. 



After discussing the subject from an historical point of view, con- 

 cluding with a description of the improved form of secondary bat- 

 tery lately invented by M. Faure, the author proceeded to state the 



*Lon., Ed., and Dub. Ph. Mag. for 1875, Vol. 50, p. 63. 

 fRep. Light-House Board 1875, p. 125, cf. Reynolds; Lon., Ed., and Dub. 

 Ph. Mag. for 1875, Vo1 - 5°> P- 7 1 - 



