1907-8.] On the Theory of the Leaking Microbarograph. 
457 
3rd and 4th September 1905. 
Time. 
Cloud. 
Wind W. 
Microbaric Dist. 
Cumulus 
Amount. 
Direction. 
Velocity. 
Mean 
Velocity. 
Extreme 
Velocity. 
Direction. 
Velocity. 
h. m. 
10 38 
9 
W. 15° N. 
17 
25 
35 
12 40 
3 
W. 15° N. 
56 
35 
50 
14 12 
W. 25° N. 
26 
15 0 
2 
W. 30° N. 
56 
34 
48 
16 4 
3 
W. 30° N. 
22 
20 
26 
16 8 
W. 30° S. 
48 
17 1 
3 
W. 45° N. 
28 
6 
10 
17 15 
3 
W. 59° N. 
22 
5 
8 
20 23 
7 
2 
0 
3 
4 
26 18 
E. 55° N. 
30 
26 23 
1 
While there is in this, as in other cases that have been observed, some 
connection apparent between the directions of the wind and cloud-motion, 
yet we see that on the fall of the wind and cloud velocity there is a 
reversion of the current of microbaric disturbances. As might be expected, 
the wind and cloud velocities go more or less together, but the velocity of 
propagation of the microbaric disturbances seems to vary independently. 
The reversion of the last-mentioned observed at 26 h 18 m may point to 
some discontinuity in the conditions of the upper air. 
Loch Earn, 7th September 1905. 
Gusty Squalls of Wind and Rain. 
At 8 h 28 m occurred one of the most remarkable microbaric disturbances 
observed during the months of August and September. The micro- 
barograph at Ardtrostan had shown considerable disturbances both of 
longer and shorter duration since midnight. At 8 h 15 m a sudden rise 
began, which reached a maximum of + 11 '5 mill, about 8 h 27 m ; then there 
was a fall in about 9 m to a minimum of — 6*5 mill. ; and finally in about 
7 m a rise to about the mean previous to the disturbance. The whole dis- 
turbance occupied about half an hour, and was accompanied by similar dis- 
turbances at Killin and Lochearnhead. The maximum and the minimum at 
Ardtrostan were sharper than at the other two stations, so that Ardtrostan 
was either nearer the origin of the disturbance, or nearer its centre if it 
was a vortex of moderate dimensions. Unfortunately, the pen came to the 
end of the Lochearnhead chart before the minimum was reached ; but the 
