248 W. B. Rogers on Rotating Rings of Air and Liquids. 
of quick but not violent puffs, each little cloud assumes near the 
aperture the form of a ring, which gradually dilating as it rises — 
retains its symmetry until it has reached the height of twoor — 
sometimes even of three feet above the opening. : 
Using a gentler and less sudden impulse we cause the ring — 
as it ascends to carry with it a train of cloudy air which forms the 
downward continuation of the inner portion of the coil. ag 
With a still lighter breathing at the mouth-piece we may expel 
the air in so gentle a wave as to be able to mark the escaping 
cloud rolling slowly over on each side of the aperture without 
breaking its connection with the cen- 
tral mass—the whole thus assuming 
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being represented. : 3 bass 
When the discharge is produced by a stronger impulse than in 
the case first mentioned, the resulting ring darts upward s0 
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» over a large apart 
each other until flatte 
ead of the mow 
