j 
612 PROFESSOR CHRYSTAL , 
way Mr WeppERBURN was able to verify with very fair accuracy Mrrian’s law for the 
uninodal and binodal periods in a trough of uniform depth: to show that for a trough 
of the same length and same maximum depth, T, is greater when the bottom is caused 
to slope by inserting a wedge * inside it, or, what comes to the same thing, that when 
T, is unaltered, C HE must be made shorter; and that then T,>4T,. The displacement 
of the uninode towards the shallow end and the greater amplitude of the wave there 
were also readily demonstrated. The foregoing experiments were made with water 
8°18 cm. deep, in a trough of length CH=39°8 cm.; and the periods were T, = 96", 
A 
s 
Iie ale 
T,='52". With a depth of 4:1 em. and C H=30°7 em. it was still possible to maintain 
a uninodal seiche of period *97", which agrees very well with the formula T = 2//,/(gd) 
applicable to a long wave. . 
Foret based his theory of seiches in part upon an interesting series of experiments 
of this kind made in 1870,t 
* To incline the trough, keeping the volume of water the same, is not the same thing. 
+ Enpr6s commenced his investigation of the complicated seiche-phenomena in the Chiemsee with a series of 
experiments on the oscillation of mercury in a vessel imitating the configuration of the lake, the results of which, on 
the whole, were in remarkable agreement with his subsequent observations, l.c., p. & 
