AS A VEHICLE OF SOUND. 
237 
Afloat. 
Wind W.N.W., W. by N. to N.W., 4 
Barometer — 
Wet bulb 59° 
Dry „ 62±° 
Ashore. 
29-7 
57° 
63° 
June 26. Partial Summary . — Maximum range for whistle and horns 9| miles, with paddles quiet ; the 
horns could have been heard further, though the wind, with a force of 4, was against the sound. On the 25th 
the maximum range, with the wind favourable, was 6 - 4 miles. Something, therefore, besides the wind must 
affect the sound-range. Sound heard at 5-4 miles through paddle-noises and slop of the sea. 
Ashore. 
W.N.W., then W.S.W. 
30 
62° 
66 ° 
Afloat 
Wind S.W. 
Barometer 30‘3 
Wet bulb 60° 
Dry „ 62° 
July 1. Partial Summary . — Maximum range Varne light-ship, 12f miles ; maximum observed on board 
the 4 Irene ’ 10^ miles. Heard through paddle-noises 6| miles. Afloat, wind almost dead against sound ; 
on shore across it. Thick haze, but acoustically a very transparent day. Horn rotated, and strengths of its 
various blasts expressed numerically ; direct or axial blast strongest. Proved that subsidence of sound at edge 
of phonic area is not due to deviation from axis, because it occurs when axis is directed along the edge. The 
American whistle did not manifest any remarkable power : this day was the first occasion of its trial. 
Wind . . . 
Barometer 
Wet bulb . 
Dry „ . 
Afloat. 
S.S.W. to S.W., 2 
30 
61° to 60° 
67° to 62° 
Ashore. 
N.W., 3, to W.S.W., 2 
29-8 
62° 
67° 
July 2. Partial Summary. — A very different day, acoustically, from yesterday. Maximum range in axis 
only 4 miles ; wind oblique and against sound ; sea noisy. Acoustic opacity of atmosphere augmented from 
the morning onwards. Near end of Dover Pier, to windward, sounds not heard ; on the other side of Foreland, 
to leeward, sounds well heard. 
Afloat. 
Ashore. 
Wind 
W.S.W. and S.W., 5 
Barometer 
30-1 
29-8 
Wet bulb 
58° 
60° 
Dry „ 
61° 
62° 
July 3. Partial Summary — 
-Maximum range at 2 p.h. under 3 miles 
: cannon scarcely heard at 2 miles. 
The obscuration of the sun by 
a cloud diminished the aerial opacity ; the sinking of the sun diminished it still 
more, and caused sound to reach men in an anchored boat, where half 
an hour previously nothing could be 
heard. Range subsequently extended beyond the Varne buoy and to the Varne light-vessel. Day singularly 
calm and optically clear : dead calm, indeed, afloat. 
Wind 
Afloat. 
Ashore. 
S.S.E., 2 
Barometer . . 
30 
29-7 
Wet bulb 
68° to 61° 
. * 63° to 59° 
Dry j> 
71° to 61° 
69° to 63° 
July 4. Partial Summary. — Maximum range probably from 4 to 5 miles : horn heard through paddle- 
noises, not the whistle. Gun-sounds superior to any thing on this day. Sounds unheard at 5| miles. 
