Beyond the limits of their own galaxy -- which was not ours -- they could not navigate in person; but in their quest for knowledge of all space and time they discovered a means of spanning certain transgalactic gulfs with their minds. They devised peculiar objects -- strangely energized cubes of a curious crystal containing hypnotic talismen and enclosed in space-resisting spherical envelopes of an unknown substance -- which could be forcibly expelled beyond the limits of their universe, and which would respond to the attraction of cool solid matter only.