Dust WJtirls, 



317 



unawares by a small dust -whirl, one at first receives the impres- 

 sion of the sudden and violent rising of a great wind. 



Red is the predominating colour of dust whirls, owing to red 

 being the predominating colour of the soils. 



The whirls are commonest in summer, on calm days, or on: 

 days Avith only a gentle breeze. These facts agree with the obser- 

 vations of investigators in other countries. After midday is the 

 most favourable period for the occurrence of dust whirls. 



Tahle of Observed Dust Whirls. 

 The following list comprises the dust whirls recorded by tha 

 Avriter in the Niagara-Kookynie and Comet Vale-Goongarrie dis- 

 tricts, with the dates of occurrence, the direction of rotation, and 

 general remarks. Where it was impossible — mainly on account of ' 

 distance — to determine the direction of rotation,* a blank has been- 

 left. In some cases, the direction given is not quite certain, 

 hence a query has ]>een added so as to express this doubt. One 

 gigantic whirl has been separately described below on account of 

 its special interest. The writer is well aware that the remarks as 

 to height and other characters of individual whii'ls are vague, but 

 the phenomena do not readih' lend themselves to accurate measure- 

 ments, and opportunity did not always permit of more definite 

 statements : — 



Direction of 



G-eneral Remarks. 



These occurred in the Niag'ara- 

 Kookvnie district. 



No details, except direction of 

 rotation were noted. 



Distant. In front of a ridpe. 

 From probable lieisfht of lat- 

 ter, the dust whirl was esti- 

 mated to be 1000 feet high at 

 the least. East of Kookynie. 



Distant. 

 Distant. 

 Low. 15 On ironstone country. 



1916. 

 Sept. 22 

 ,, 22 

 „ 25 



Anticlockwise (?) 



15. " Low " means that the dust whirl as seen by the naked eye reached to 

 only a small height from the surface of the ground, in some instances, not: 

 more than 20 feet, and even less. 



