ATMOSPHERE AND THE ACOUSTIC EFFICIENCY OF FOG-SIGNAL MACHINERY. 
283 
Table 12. —Long Range Acoustic Survey, September 17, 1913. 
Father Point Meteorological Observations. 
Barometer, 30 - 14. Air temperature : dry bulb, 54° F.; wet bulb, 52° F. 
Wind : 10-11 a.m., velocity, 11 miles per hour from W.; 11-12 a.in., 15 miles per hour from W. 
Weather, cloudy. Clouds moving from W. Sky completely clouded over. 
Phonoheteb Readings. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
1 
0 -2 
14 
* 0 -8 
27 
2 0 
40 
o -o 
53 
0 6 
2 
0-2 
15 
2 -0 
28 
0 -5 
41 
— 
54 
0 -7 
3 
0'3 
16 
2 3 
29 
1 '8 
42 
— 
55 
0 -8 
4 
0 -2 
17 
0 -9 
30 
1 8 
43 
— 
56 
0-7 
5 
0 T 
18 
1 6 
31 
1 6 
44 
o -o 
57 
0 8 
6 
0 '3 
19 
i -o 
32 
0 9 
45 
0 -0 
58 
0-7 
7 
0 -35 
20 
0 -6 
33 
0 9 
46 
0 -0 
59 
0 -6 
8 
0 -5 
21 
0 '6 
34 
0 '3 
47 
0 -0 
60 
0-6 
9 
0 -7 
22 
— 
35 
0 -3 
48 
0 -0 
61 
0-5 
10 
0 8 
23 
1 6 
36 
0 -3 
49 
0 -1 
62 
0 -6 
11 
2 '3 
24 
0 9 
37 
0 -2 
50 
0 -3 
63 
1 2 
12 
2-1 
25 
0-8 
38 
0-0 
51 
0 -5 
13 
1 -8 
26 
1 -4 
39 
o -o 
52 
0 8 
Remarks. 
10.29 a.m. Left Rimouski wharf. Sea smooth. Sky completely overcast. Smoke from ship hangs low. Air 
temperature, 56° F. 
1. Time, 10.48 a.m. Ship commences circular course at ^-mile radius. 6. Ship clear of acoustic shadow of wharf. 
12. Echoes marked, audible for 10 seconds. 21. Time, 11.08 a.m. Ship turns back along same course. 38-39. Signals 
audible. 40. Signal barely audible. 41-43. Ship turns outward from fog-signal to take up circular course at 1 mile radius. 
Signals inaudible. 44. Time, 11.32 a.m. Ship commences circular course. Signal inaudible. 45-46. Signals just audible. 
47. Signal audible. 63. Time, 11.51 a.m. Ship turns into Father Point wharf. Air temperature, 54° F. 
. Control Observations. 
End of Father Point wharf .—Mean of three phonometer readings, 1 ’8. 
Control -station.—Phonometer reading, 4 '9. 
Mean air pressure operating diaphone, 24 - 7 lbs./sq. in. .above atmospheric. 
VOL, CCXVIII.—A. 
