F's 1 
Ri 
, 
. ie 
100 HUGH CHARLES KIDDLE. 
still smouldering in places. Hearing an unusual noise, I looked 
around, and perceived a large whirlwind that had settled over a 
floor, about one hundred yards away. I must explain that a — 
“floor” is a place (in the paddock), where the farmer stands his 
winnower to clean the grain as it is brought in by the stripping 
machines. The chaff is left on the ground, and forms a floor of 
about a foot in depth. On this floor the chaff was damp under- 
neath and therefore only smouldering, The whirlwind sucked up 
the smoke, forming a greenish-black column about three feet in 
diameter and fifty feet in height. As there was very little wind 
at the time, the whirl remained over the “ floor ” for the space of 
a few minutes, and it was accompanied by a roar audible from the 
place where I first noticed the whirl, a distance of one hundred 
yards. I did not attribute the roar to the whirl alone; in this 
case it was doubtless caused by the combined action of the smoulder- 
ing fire and the whirl, thus producing a huge natural draught. 
After passing the floor, the whirl proceeded as a comparatively 
small specimen of its class, as the ground it then passed over had 
very little loose material left on it to make the column visible at 
any distance. Even from this example it will be seen that a large 
percentage of these phenomena must necessarily pass unnoticed, as 
the greater part ‘of the surface furnishes none of the material 
required to make their presence perceptible. This fact alone will 
help to account for the paucity of the observations recorded, as I 
only noted down those I could ascertain some definite result from. 
IT am informed that dust whirls occur with greater frequency 
and violence in the northern and western parts of New South 
Wales than in this district, a fact which may be partly accounted 
for as the soil isin parts more sandy. Their violence being greater 
would indicate them to be caused by ascending air currents, the 
outcome of the westerly wind and low barometer as previously 
advanced or suggested as the origin of these whirls. 
Thus the more prominent characteristics of these whirls have 
been detailed from observation. It would doubtless be easy to 
build up a theory with regard to their origin, by assuming the 
