SEICHES AND OTHER OSCILLATIONS 
77 
by the time the wave has reached Picnic Point a shallow minimum 
has developed in front of the maximum. If the wave had travelled 
as a solitary long wave, it would have taken only about 7™ to travel 
from the binode to Picnic Point. 
After the wave reached St Fillans it seems to have been reflected 
backwards and forwards between the ends of the lake, at first with a 
good deal of irregularity, but gradually it developed the character- 
■8-osr 
iV^ til ^ 
/3 Hrs 
may 
istics of a regular dicrote seiche. There are two points (easily seen 
on the binodal limnogram), viz. 16^^ and 17^ 20™, where the range of 
the seiche was suddenly increased, evidently by barometric disturb- 
ances which occurred at these times. The increase at 17'^ 20™ 
have been partly due to the heavy shower. 
At 17^ 20™ on the 23rd the dicrote is fully developed (2U = ll-5, 
2B = 7*0). It retains its character, with gradually decreasing range, 
until a little before 24^^ on the 24th. About that time the micro- 
barograph at Killin shows disturbances with periods T==10™, 
