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Proceedings of the Royal Society of Edinburgh. [Sess. 
being about 5 mill., and the interval between the minima about 25 m . To 
this corresponds at Lochearnhead a double-crested maximum, the whole 
range being about 5 mill. At Ardtrostan there is scarcely anything that 
can be identified as belonging to the same disturbance. This disturbance 
cannot, therefore, have extended over the whole of Loch Earn. 
One well-marked maximum, which passed Ardtrostan at 16 h 34 m , can 
be identified at the other two stations. Its direction and velocity are 
given in the table on p. 454, and it will be seen that it followed more 
or less the same path as the drift of the lower clouds, and went in a 
direction opposite to the much more marked microbaric disturbance which 
occurred earlier in the day. 
During the day the conditions in the upper and lower atmosphere were 
distinctly different; and there must have been at least one well-marked 
surface of discontinuity. 
( Issued separately August 13 , 1908 .) 
