1010 Wisconsin Academy of Sciences, Arts, and Letters. 
corresponding to the great change of temperature in the deeper 
water, does not represent a corresponding and equally, rapid 
vertical movement of the water, or indeed any considerable 
vertical movement at all. If this and similar temperature 
changes are due to seiches, then the vertical movements of the 
isotherms, as platted on the diagram, represent equally well 
the vertical movements of the water. Wedderburn does not 
hesitate to accept this result. He assigns an occasional ampli¬ 
tude of 200 feet to the temperature seiche (’07, p. 426) and 
thinks that an amplitude of 100 feet is nothing out of the 
ordinary. He also states (’07, p. 422) that on August 17 
the temperature rose 8.3° F. in 15 minutes at a depth of 100 
feet. This change, if due to the lowering of the surface of 
the thermocline, means a movement of at least 50 feet in the 
same time, and in the course of the general temperature move¬ 
ment of this day there would have been a depression of the 
thermocline amounting to over 100 feet during two hours. I 
find it difficult to believe in such great movements of the hv- 
polimnion. They are so large and so rapid that they should 
cause serious disturbances at the surface of the water, which 
have never been observed. But if the explanation of these 
temperature changes, which I ’ have given above, is accepted, 
no such violent and rapid movements of the liypolimnion need 
be assumed. As the space between the yacht and the shore 
was gradually filled with warm water, forced to the end of 
the lake by the wind, the colder water was crowded downward 
and outward. The front of this growing mass of warm water 
gradually moved out into the lake as new additions were made 
to it, and when it reached the observing station the thermone- 
ter recorded a very sudden and great rise of temperature, which 
however, involved no corresponding movement of the water 
but only a comparatively small displacement, chiefly lateral. 
The complex phenomena, cansed by wind, with their re¬ 
sulting temperature changes, cannot be readily analyzed from 
observations made at a single point, but before we can ac¬ 
cept temperature seiches a's their cause, there must be ob¬ 
servations sufficient in number and position to exclude other 
and more easily received explanations. 
