ATMOSPHERE AND THE ACOUSTIC EFFICIENCY OF FOG-SIGNAL MACHINERY. 2 79 
Table 8. —Long Range Acoustic Survey, September 9, 1913. 
Father Point Meteorological Observations. 
Wind : velocity, 10-11 a.m., 14 miles per hour from E.; 11-12 a.m., 14 miles per hour from E. 
Weather partly clear. Clouds moving from N. Sky 80 per cent, clouded over. 
Phonohetee Readings. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
1 
7 
13 
1 2 
19 
25 
o -o 
2 
— 
8 
o -o 
14 
1 *2 
20 
— 
26 
0*2 
3 
— 
9 
0 *0 
15 
0 '4 
21 
— 
27 
0'6 
4 
— 
10 
0 -2 
16 
0*2 
22 
— 
28 
0 *5 
5 
— 
11 
0 -7 
17 
0*0 
23 
— 
29 
0 *1 
6 
12 
2 3 
18 
— 
24 
— 
30 
o -o 
Remarks. 
10.15 a.m. Left Rimouski wharf. Sea moderate ; waves breaking. Sky overcast by light clouds. Air temperature, 52° F. 
4. Signal distinctly heard from bridge but not from deck. 5-6. Inaudible from deck. 7. Signal distinctly heard from bridge 
but not from deck. 8. Signal first heard from deck. 9. Audible. 12. Time, 10.56 a.m.; ship turning back along same 
course. 13-14. Phonometer in acoustic shadow of deck house. 17-19. Inaudible. 20. Barely audible. 21. Inaudible. 
22. Time, 11.06 a.m.; course back to fog-signal; signal barely audible. 23-24. Just audible. 25. Audible. 27. Time, 
11.11 a.m.; course outwards from fog-signal. 30. Signal just audible. 31. Signal not heard. 32. Time, 11.17 a.m., course 
changed; signal not heard. 33-34. Inaudible. 35. Barely audible. 36. Time, 11*21 a.m.; course changed towards 
fog-signal; signal inaudible. 37. Inaudible. 38. Barely audible. 39-40. Just audible. 41. Time, 11.26 a.m.; air 
temperature, 53° F. 
• Control Observations. 
End of Father Point wharf. —Mean of six phonometer readings, 2*5. No echoes heard. 
Control station. —Mean of four phonometer readings, 7*5. 
Mean air pressure operating diaphone, 18*3 lbs./sq. in. above atmospheric. 
