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THE ROYAL SOCIETY OF CANADA 



quency 348 seems to carry better as far as 9,400 feet, and the sixth 

 partial of frequency 1,044 carries well as far as 8,300 feet; while these 

 observations favor the master- tone, they are not sufficient to show 

 that any other tone having a frequency of less than 1,000 may not be 

 equally efficient. The energy is distributed over many partial tones 

 in very capricious proportions, and there is yet much to be desired 

 in the control of the output of energy of the diaphone. 



860 1560 /If 3250 4890 5900 6300 9*0 J0500 13500 



Fig. 1. — Variation of Loudness of Fog Signals with Distance 



The information contained in Table II. may be represented by 

 the diagram. Fig. 1. If a sound passing outward has the loudness 

 10,000 at the station distant 860 feet from the horn, and if the sound 

 is transmitted according to the simple inverse-square law without 

 absorption or dissipation, its curve of loudness would be the smooth, 

 heav>' line h. This curve crosses the ordinate for the distance of 860 

 feet at a point above the base line equal to three times the height of 

 the portion of the diagram here shown. It would be interesting to 

 compare with this curve the transmission curves for each partial 

 tone, but since so few observations are available, the averages of the 

 energies of the four lower partial tones, numbers 1, 2, 3 and 4, and of 

 the four higher partials, numbers 7, 8, 9, 10, for each sound at each 



