240 
PROFESSOR TYNDALL ON THE ATMOSPHERE 
Afloat. 
Ashore. 
Wind 
W., 2 
W.S.W., 3 
Barometer 
30-1 
29-8 
Wet bulb 
54° to 56° 
54° 
Dry „ 
56° to 59° 
59° 
October 20. Partial Summary. — A day 
of atmospheric variation and consequent variability of sound-range ; 
strong wind, high sea, and much local noise. At 5 - 7 miles to leeward syren more 
distinct than gun ; at some 
shorter distances gun-sound quenched by local noises, but not so with the syren-sound. Across the wind the 
syren was heard through paddle-, sea-, and wind-noises at 5 miles ; horns (two small ones) weak at 3£ and 
inaudible at 4 miles. Gun-report not picked up by some ears so well as the hard and sustained sound of the 
syren ; horn a soft musical sound, inferior to explosive blast of the syren. 
Afloat. Ashore. 
Wind W. by S. to N.N.W., 6 to 8 N.N.W., 5 to 7 
Barometer .... 29 - 9 29 - 6 
Wet bulb 55° to 49° 55° to 42° 
Dry „ 55° to 51° 57° to 45° 
October 21. Partial Summary. — Strong wind, high sea. At miles in the axis, paddles going, wind across, 
syren heard clearly ; gun seen, but not heard : horns lost after 4 miles. At 4| miles in axis vessel stopped 
in the midst of heavy rain and high wind ; gun, horns, and whistles heard, but syren hurst out with sudden 
power, overmastering them all. 
Afloat. Ashore. 
Wind W.N.W. to W., 5 to 7 W., 5 
Barometer 29-8, falling 29-6, falling 
Wet bulb , . 48° to 52° 46° 
Dry „ 49° to 52° 48° 
October 22. Partial Summary. — Land-observations only. At the Cornhill Coastguard Station, distant 1 mile, 
with a very strong wind blowing directly against the sound, the syren and horns (the latter pointed towards us) 
were heard distinctly, while the smoke of the gun was seen, but the sound was not heard. Sheltered from the 
wind the gun was heard distinctly. At a greater distance, sheltered from the wind by a furze bush, the syren 
and horns were heard, hut not the gun. Gun-sound liable to be obliterated by a passing puff of wind. To 
leeward, on the cliff beyond St. Margaret’s Bay, the gun-report was very loud, the syren and horn-sounds being 
also very powerful. 
Afloat. ’ Ashore. 
Wind .... 
Barometer 
Wet bulb 
Dry „ 
W.S.W., 5 
29-1 
56° to 49° 
57° to 52° 
October 23. Partial Summary. — Land-observations only. Strong wind, at times increasing to a gale. 
Mr. Avr.es, 600 paces to windward, heard syren distinct, horn indistinct, gun not all. Syren also heard 
distinctly through thunderstorm ; gun and horns inaudible. At 1| mile in same direction syren always heard, 
generally distinct and strong ; gun and horns only heard 3 times. Mr. Douglass, to leeward, carried syren- 
sound to miles, having lost the gun at . During thunderstorm and heavy rain, sounds were heard plainly 
at 2| miles which had previously been inaudible. In rear of instruments effective range of sounds about a mile, 
syren predominating. 
Wind ... 
Barometer 
Wet bulb 
Dry „ 
Ashore. 
W. and W.S.W., 6 to 8 
28'6, rising 
50° 
52 ° 
Afloat. 
