409 Dr. T. H. Havelock. The Propagation of [Aug. 26, 
turbance if it were unlimited. In the rear of the main group we have also 
a series of alternating groups, following each other much more quickly and 
with their wave-lengths and velocities less separated out than in the front of 
the main group. Hence the disturbance in the rear, especially at distances 
from the origin not very great, may be expected to consist of small, more 
YJ 
Fie. 1. 
irregular, motion resulting from the superposition of this latter system of 
groups, thus there will be a more distinctive rear of disturbance moving 
forward with velocity $V. These inferences may be compared with some 
results given in Lord Kelvin’s later papers. Starting from a solution of the 
equations for an initial elevation in the form of a single crest, the results were 
combined graphically so as to show in a series of figures the propagation of 
12 
