227 
1907-8.] Professor C. G. Knott on Seismic Radiations. 
uniconstant theory developed by Navier and Poisson ; for as soon as an 
seolotropic stress is applied to our rods and wires, the material ceases to be 
truly isotropic. It would appear from the calculation just made that the 
interior of the earth is in a condition which at each point might be described 
as isotropic ; and the relation required by the uniconstant theory is accur- 
ately satisfied by the constants calculated from the propagation of the two 
phases of the preliminary tremors when these are assumed to be respectively 
the compressional and distortional vibrations.. 
We shall now consider the significance of the last column of figures in 
the tables on pages 222 and 223, the columns headed “ energy distribu- 
tion.” The meaning of the figures is best explained by consideration of 
particular cases in connection with the accompanying diagram.* 
The diagram represents a section of the globe, and some of the particulars 
corresponding to each of the cases are figured on the one half. The full 
lines show the paths of the seismic disturbances as they radiate out from 
the origin O. Each ray corresponds to one of the particular set of values 
calculated and tabulated on pages 222, 223. The following short table 
* Reproduced by permission of the Delegates of the Clarendon Press, the publishers of 
my book on The Physics of Earthquake Phenomena. 
