prolonged into the transparent air above. It is a fact of great 1n- 
terest that even in these tall cylindrical whirlwinds, the rotary 
motion was perfectly obvious throughout their entire length, roll- 
ing the black smoke in wreaths like carded wool to the top of the 
visible column, and probably beyond, as we may infer from thelt 
rapid motion.* Towards the top, these whirlwinds were some- 
times bent by the wind. This change of direction was more 
sudden or abrupt than is represented in the plate, and the whitl- 
large fires, or even from the paost powerful furnaces, ejected in a column a 
: aby 
movement that we witness in the atmosphere. ars Saale 
the spiral motion of the column, which presses onward in the direction of its 4 cd 
until it reaches a limit of elevation which is yet unknown. Even the ring 207m" 
which is sometimes seen to form at muzzles of cannon or the ejection pipe 
high pressure steam engines, appears to possess the qualities of a projectile, notwIY™ 
anding its unfavorable form.” . 
