SMALL WHIRLWINDS. 93 
base, and increasing in width with altitude, gave the appearance 
of an inverted cone. These cannot be considered as parallel cases, 
however, as although the visible effects resemble one another, the 
causes are different, there being wind in one case, calm in the 
other. <A description of the appearance of these whirls can only 
be considered general, however, as each particular one has its own 
peculiarities derived from the nature of the locality over which it 
passes, and the condition of the wind, if any, at the time, as 
previously alluded to. 
The second characteristic, viz., the difference of the directions. 
in which these whirls revolve on their axes—relatively—is by far 
the more important, and is peculiar and difficult to investigate. The 
observer may see two of these whirls appear, within a few minutes, 
in nearly the same place, each revolving on its axis in an opposite 
direction to the other. If one be represented as revolving right 
handedly, as in Fig. 1, then the other will be revolving in a left. 
handed direction as in Fig. 2. 
Compass t North Compass i) North 
Compass Compass 
Compass. 
East West 
East 
Compass South Compass South 
Now, in order to conform to the general law of storms for the 
Southern Hemisphere, a whirl produced by an ascending current 
of air should revolve in a right handed direction, or in the same 
direction as the hands of a watch, as in Fig. 1. The whirls seen 
in this district, however, are very erratic in their rotatory motions, 
and it was this apparent disregard for the manner in which they 
ought to revolve, in order to follow the general law, that attracted 
my attention to them in the first instance, and prompted the 
question : how is this irregularity to be accounted for? To strike 
