230 Proceedings of the Royal Society of Edinburgh. [Sess. 
It would be possible, though somewhat laborious, to work out the surface 
distribution of energy for several depths of origin along the lines indicated 
above. If this were done, and if instruments could be constructed to give 
an accurate measure of the energy associated with seismic movements 
at the surface, we should be in possession of a method for determining the 
depths of origins — a problem which has hitherto baffled all endeavours. 
(Issued separately April 9 , 1908 .) 
