ATMOSPHERE AND THE ACOUSTIC EFFICIENCY OF FOG-SIGNAL MACHINERY. 293 
Test No. 4 (continued). 
No. of 
observation. 
Mean pressure 
above 
atmosphere, 
lbs./sq. in. 
Air consumption 
in cubic feet 
per second. 
Maximum powei 
possible in H.P. 
(W). 
Temperature 
difference, 
sounding and 
silent 
(89 — 86'). 
Power emitted 
as sound and 
consumed in 
driving piston 
in H.P. 
(«’)• 
Acoustic 
efficiency 
(»; = ?e/W). 
1 
7'7 
3 2 
3 6 
° C. 
0 -54 
0 '06 
0 017 
2 
9 9 
4 6 
6 3 
1 52 
0 '24 
0'038 
3 
11 -8 
4 '9 
7 7 
2 -31 
0 '40 
0 '052 
4 
13 '8 
5 6 
9 '8 
2 66 
0 '53 
0 054 
5 
15 -7 
5 -9 
11 2 
3-08 
0 '63 
0 056 
6 
17 6 
6 '6 
13 5 
3 32 
0 -77 
0 057 
7 
19 o 
7 -7 
16 -8 
3 '54 
0 '96 
0 057 
8 
21 3 
8'0 
18 3 
3 -66 
1 03 
0 '056 
9 
23 3 
8 -5- 
20-5 
2 -66 
0-80 
0 039 
10 
25 -1 
9 0 
22 -8 
2 T9 
0 -70 
0 031 
11 
27 0 
10 1 
26-3 
2 '14 
0 '76 
0 029 
12 
28 9 
11 8 
31 9 
2'07 
0 '86 
0 '027 
13 
30 '7 
13 4 
37 '6 
2 *44 
1 T5 
0 '031 
Test No. 5. Air Consumed in Driving Cylinder. 
No. of 
observations. 
Mean pressure 
above atmosphere, 
cm. mercury. 
Pressure drop 
in time t. 
ITi-Pi)- 
cm. mercury. 
t. 
seconds. 
Mean pressure 
above atmosphere, 
lbs./sq. in. 
Air consumption, 
cubic feet/seconds. 
1 
47 0 
12 '0 
260'6 
9 T 
0 '48 
2 
58 '2 
10 '3 
183 '4 
11 '2 
0 '59 
3 
68 '3 
10 0 
161 '4 
13 T 
0 '65 
4 
78 T 
9 '7 
142 '6 
15 T 
0 '72 
5 
88 0 
10 0 
129'8 
17 '0 
0 81 
6 
98 '0 
10 0 
118 '2 
18 '9 
0'89 
7 
108 '0 
10'0 
109 '0 
20'8 
0 '96 
8 
118 0 
10 '0 
93 '2 
22 '8 
1 13 
9 
128 T 
9 '8 
93'4 
24 '7 
1 Tl 
10 
13S 0 
10 0 
78 '0 
26 '6 
1 "36 
11 
14& '0 
9 '5 
63 '2 
28 '6 
1 '58 
12 
157 '9 
10 -2 
58 '2 
30'5 
1 '81 
