ATMOSPHERE AND THE ACOUSTIC EFFICIENCY OF FOO-SIGNAL MACHINERY. 285 
Table 14.—Long Range Acoustic Survey, September 20, 1913. 
Phonometeb Readings. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono¬ 
meter. 
Position 
No. 
Phono- i 
meter. 
1 
21 
0 '7 
41 
0 -4 
61 
3 2 
81 
0 3 
2 
o -o 
22 
0 '4 
42 
0 '2 
62 
3 -0 
82 
0 ‘o 
3 
o-o 
23 
0 '3 
43 
0 -25 
63 
3 0 
83 
0-6 
4 
0 05 
24 
0 3 
44 
0-15 
64 
2 4 
84 
10 
5 
0 6 
25 
0-2 
45 
0 2 
65 
3'2 
85 
0 9 
6 
0 -5 
26 
0-3 
46 
0 '5 
66 
2 6 
86 
0 -5 
7 
1 0 
27 
0 2 
47 
0 1 
67 
4-0 
87 
1 2 
8 
1 0 
28 
01 
48 
0 '25 
68 
4 ’5 
83 
0 9 
9 
5 *5 
29 
0 1 
49 
1 1 
69 
4 7 
89 
1 -2 
10 
— 
30 
0 -05 
50 
1 '2 
70 
5 0 
90 
1 '2 
11 
2 3 
31 
0 0 
51 
0 6 
71 
1 2 
91 
1 6 
12 
2 -0 
32 
o-o 
52 
1 4 
72 
0 6 
92 
2 '4 
13 
1 2 
33 
o -o 
53 
1 -2 
73 
— 
93 
2 4 
14 
2 0 
34 
0 -3 
54 
1 
74 
0 6 
94 
1 8 
15 
0 9 
35 
0 -3 
55 
1 -2 
75 
0 6 
95 
2 0 
16 
1 -o 
36 
0 -3 
56 
1 -o 
76 
0 -3 
96 
1 6 
17 
0-9 
37 
0-2 
57 
1 '4 
77 
0 6 
97 
1 6 
18 
0 7 
38 
0-2 
58 
3 2 
78 
0 -4 
98 
0 -6 
19 
0 ’4 
39 
0 -15 
59 
2 9 
79 
0 7 
99 
— 
20 
0 -4 
40 
0 -2 
60 
2 l) 
80 
0-3 
100 
0 -6 
Remarks. 
10.13 a.m. Left Rimouski wharf. Sea smooth. Sky unclouded. Slight breeze from £. Air temperature, 52° F. 
1 . Signal first heard from bridge. 2. Signal first heard from deck : barely audible. 3. Audible. 12. Time, 10.35 a.m. 
Start of course away from fog-signal. 17. Echo audible about 25 seconds. 31-32. Audible. 33. Just audible. 40. Time, 
11.06a.m. Ship turns back along same course. 42. Ship stopped; fog-signal on port side. 43. Ship stopped; fog-signal 
straightahead. 44. Ship stopped ; fog-signal on starboard side. 45. Ship stopped; fog-signal straight ahead. 46. Ship 
starts in course towards Father Point. 67. Air temperature, 56°F. 70. Time, 11.40 a.m. Course altered to take up circular 
course at l mile radius. 71-73. Phonometer in acoustic shadow of deck house. 74. Time, 11.43 a.m. Commencement of 
circular course at mile. 98. Ship enters acoustic shadow of wharf. 100. Time, 12.09 p.m. Course set for Father Point 
wharf. Air temperature 58° F. 
Control Observations. 
End of Father Point wharf. —Mean of two phonometer readings, 375. 
Control station .—Mean of two phonometer readings, 7 'I. 
Mean air-pressure operating at conclusion of observations, 246 lbs./sq. in. above atmospheric. 
Note. —Observations 42-45 were taken with a view to determining whether the effect of the ship’s hull when presented 
broadside and bow-on was noticeable on the intensity of the sound as measured at the phonometer. It was concluded that 
within the limits of variation due to changing atmospheric conditions such an effect is not noticeable. 
