The primary goal of the paper is to demonstrate that a circular
jet
of inviscid liquid,
which issues from a nozzle at an angle to the gravitational field, can
sustain a self-excited linear global mode. The mode is found for the
flow that is locally convectively
unstable at every point, i.e. has no region of local absolute instability.
A simple
experiment shows that the mode can evolve into a wave of finite amplitude,
which is
localized in space near the nozzle.
Section 2 of the paper summarizes some recent developments in the linear
theory
of stability of weakly inhomogeneous flows.