238 
PROFESSOR TYNDALL ON THE ATMOSPHERE 
Afloat. 
Ashore. 
Wind 
W.S.W., 7 

Barometer 
29-9- 
29 ? 5> 
Wet bulb 
61|° 
6-1* 
Dry „ 
64° 
64° 
October 8. Partial Summary . — Maximum range over 9 miles ; howitzer loud, syren clear, horn feeble. No 
wind at the time of maximum, but following closely upon heavy squall of rain and hail. Previously, at 5J 
miles the sounds had been much more feehle. 
Afloat. Ashore. 
Wind Calm to W.S.W., 3, to N. by W., 2 W.S.W., 2, to N.W., 3 
Barometer 29B 29‘4 
Wet bulb 52° to 48° 50° to 45° 
Dry „ 55° to 48° 54°' to 46° 
October 9. Partial Summary. — Maximum range 1\ miles ; syren faint but distinct. Syren better than 
gun or horn with wind across ; gun better than syren or horn with wind directly favourable to sound. Good 
and serviceable sound from syren heard at 3 miles distance to windward, ‘ Galatea ’ steaming at full speed. 
Afloat. 
Ashore. 
Wind 
W.S.W., 3 to 6 
W.S.W., 5 1 
Barometer 
29-9 ... 
29-6. 
Wet bulb 
54° 
49° 
Dry „ 
58° 
55° 
October 10. Partial Summary . — The syren maintained its superiority during land-observations : deep in 
the sound-shadow both its direct sound and long-drawn echoes were heard when the horn and its echoes were 
inaudible. A strong wind was blowing against the sound at this time. 
October 11. Partial Summary. — In the land-observations of this day the syren proved itself superior to 
the gun against a strong wind : indeed at 550 yards dead to windward of the station the smoke of the gun 
was seen, but no sound heard, whilst at the same time the syren was piercingly intense ; to leeward the gun- 
sound travelled a very much greater distance. The shortness of the gun-sound is not favourable for the pur- 
poses of signalling. Moderate gale from S.W. all day. 
October 13. Partial Summary . — 2| miles E. of station, syren superior to horn, Canadian whistle, or gun. 
Same distance W. of station, gun louder than any thing ; then syren. Canadian whistle equal to horns on both 
sides. In the axis horn better than whistle. All sounds heard during descent of very heavy rain. Locality 
of station discovered, when hidden in thick mist, by sound alone. 
Afloat. 
Wind. N.W. by W.,.2 to 4 
Barometer 29-7 
Wet bulb 57° to 53° 
Dry „ 58° to 54° 
Ashore. 
N.N.W., 3 
29-3 
52° to 49° 
55° to 50° 
October 14. Partial Summary. — Maximum range 10 miles ; in the morning at the Yarne buoy, the distance 
being 7f miles, all sounds well heard. With a changed atmosphere at the same spot, four hours later in the 
day, the syren was feeble and the gun and horns not heard. It was not the wind which caused this difference, 
for it had then the same direction and force as in the morning. At 5 miles in the axis the sounds were all 
much more feeble than at 7f miles at the Yarne buoy, which was out of the axis, in the morning. At 4 miles 
to leeward the syren was strong, the gun loud, horns and Canadian whistle plainly heard. 
