For this case
In this case it can be shown that
contours of which are shown in Fig. 2 for n = 1 to 20, taking
units of 
such that 
= 1.
In contrast to the short gravity wave case, new waves are formed
at the leading part of the wave group and are lost at the
trailing part.
This is because the group speed 
exceeds the phase speed
for capillary waves, in contrast to short
gravity waves.