1907-8.] On the Theory of the Leaking Microbarograph. 455 
extent of the Loch Earn observations are not such as to justify us in 
doing more than raising the question. 
To give some idea of the general connection of the microbaric dis- 
turbances with other phenomena, I append the following notes on three 
specially interesting days. 
Loch Earn, 21st August 1905. 
A rainstorm from S.W. began about 8 h 30 m , partially cleared about 9 h , 
came on heavier about ll h , and continued with gusts of wind till 18 h 10 m , 
when the rain stopped and the sky cleared. The total rainfall during the 
day was 0'88 in. 
At Ardtrostan at 9 h the wind was E., velocity 10 (mile/hour) ; the 
clouds, 1, were coming from S. by E., and the waves on the lake were 
coming from E. At 20 h 29 m the wind was S., very light ; the clouds were 
coming from S.W., and the waves on the lake running from W. These 
surface waves were not high during any part of the day. 
During the day the mean velocity of the wind rarely exceeded 10 
(mile/hour), and was for the most part less. The extreme velocity in the 
gusts occasionally reached 15 or 20, and between I7 h and 18 h 15 m the 
gusts were very frequent, the mean velocity sometimes reaching 15, and 
the extreme 25. 
The standard barometer at Balimeanach fell 0'233 in. from 9 h to 22 h , 
and the open-air temperature at both these hours was 53 o, 0 F. 
Fig. 9 shows the three microbarograms at Ardtrostan, Killin, and 
Lochearnhead ; part of the anemogram at Ardtrostan ; and also the 
limnogram taken near St Fillans. The direction and velocity of pro- 
pagation of some of the maxima and minima on the microbarograms are 
given in the table on p. 454. 
Loch Earn, 3rd September 1905. 
Westerly Gale. 
After six hours or more of calm, the wind began to rise about 2 h 36 m . 
By 3 h 36 m it had reached a mean velocity of 17 (mile/hour), and it was 
fluctuating between 15 and 12 just before 7 h . Immediately after 7 h it had 
shot up to a mean velocity of 25, and between 7 h and 8 h was blowing a 
gale of 35 mean velocity, the extreme on one occasion being over 52. 
About 8 h 30 m there was a rather sudden decline, and at 9 h 10 m the mean 
velocity was 10. Thereafter it rose again, and at ll h there was a gale of 
30. This was maintained, with extreme gusts, occasionally reaching 54, 
