ATMOSPHERE AND THE ACOUSTIC EFFICIENCY OF FOG-SIGNAL MACHINERY. 
281 
Table 10.—Long Range Acoustic Survey, September 12, 1913. 
Father Point Meteorological Observations. 
Wind : velocity, 10-11 a.m., 10 miles per hour from W.; 11-12 a.m., 9 miles per hour from W. 
Weather, cloudy. Clouds almost stationary. Shy completely overcast. 
Phonometee Readings. 
Position 
No. 
Phono¬ 
meter. 
1 
2 
o -o 
3 
o -o 
4 
0 0 
5 
0 0 
6 
o -o 
7 
o -o 
8 
— 
9 
— 
10 
0 -0 
11 
0 -1 
12 
0 7 
13 
3 3 
14 
1 5 
15 
2 1 
Position 
No. 
Phono¬ 
meter. 
16 
0 7 
17 
0-3 
18 
0 9 
19 
0-6 
20 
0-3 
21 
0-4 
22 
0-3 
23 
0-3 
24 
0-2 
25 
o-i 
26 
0 '2 
27 
0 2 
28 
0-2 
29 
0-2 
30 
0 1 
Position 
No. 
Phono¬ 
meter. 
31 
0 '2 
32 
0 1 
33 
O'l 
34 
0 -05 
35 
0-2 
36 
0 '3 
37 
o-i 
38 
0'05 
39 
01 
40 
0-0 
41 
0-0 
42 
0-0 
43 
o-o 
44 
0 T 
45 
01 
Position 
No. 
Phono¬ 
meter. 
46 
0 0 
47 
0 T 
48 
0 1 
49 
01 
50 
0 -2 
51 
01 
52 
0 T 
53 
0 -15 
54 
0-2 
55 
01 
56 
0 T5 
57 
0-3 
58 
0-3 
59 
0 '2 
60 
0-15 
Position 
No. 
Phono¬ 
meter. j 
61 
0 -2 
62 
0 2 
63 
0T5 
64 
0-2 
65 
0-3 
66 
0*3 
67 
0-4 
68 
0-4 
69 
0-6 
70 
0-8 
71 
1 0 
72 
1 '4 
73 
2-0 
Remarks. 
10.42 a.m. Left Rimouski wharf. Sea smooth. Sky completely overcast by heavy clouds. Air temperature, 52° F. 
1. Time, 11.0 a.m. Signal first heard from deck. 2-3. Just audible. 4. Audible. 5-7. Just audible. 8. Inaudible. 
9. Barely audible. 10. Audible. 14. Phonometer in acoustic shadow of deck bouse. 15. Time, 11.14 a.m. Ship turns to 
take up course away from fog-signal. 16-17. Phonometer in acoustic shadow of deck house. Echo audible for about 6 
seconds 41. Time, 11.43 a.m. Ship turns back along same course. 71. Ship turns into Father Point wharf. Air tempera¬ 
ture, 51° F. 
Control Observations. 
End of Father Point wharf. —Mean of five phonometer readings, 1 *0. 
Control station. —Phonometer reading, 3 '9. 
Mean air 'pressure operating diaphone, 22 '6 lbs./sq. in. above atmospheric. 
