Last Whirls, 315 



>sand, feet; and Free7 mentions that they are from a few feet to 

 hundreds of feet in height. I. C. Russell remarksS that these 



-.columns of dust are often 2000 or 3000 feet, or even more, high. At 

 various heights, according to atmospheric conditions, the dust 

 tends to spread out horizontally, and so becomes invisible. 



Dust columns are slender. Free remarks that they are a few 

 inches to several f^t in diamet^r<.9 Various observers liave 

 pointed out that when seen at a distance, they resemble water- 



. spouts, and that they mostly occur in calm summer weather. 



Previous Australian Literature. 

 Of Australian occurrences, the writer has found few records. 

 D. W. Carnegieio briefly refe*rs to the occurrence of ''willy- 

 willies" in arid Western Australia, and states they are sometimes 

 -of great violence. J. W. Gregory, with regard to Central Aus- 

 tralia, refers to the "dark A\^hirling pillars of sand which sloAvly 

 travelled up the valley'^; also to "three tall columns of dust 

 w^hich were travelling straight towards us"; and again, to "the 

 dust travelling chiefly in two whirlwinds. "H D. Mawson has 

 ^describedi2 the "willy-willy" of the Broken Hill district, 

 pointing out that they are of the nature of small cyclones, like 

 water-spouts in outline, and that they are columns usually about 

 20 feet in diameter, rising to a height of several thousand feet. 

 A. Montgomery has remarkedi^ in connection with the Western 

 Australian goldfields country, that "on any fine day in summer 

 it is quite usual to be able to see; several whirlwind clouds of dust 

 ■ dancing over the landscape at one time." 



These are the only Australian records that the writer is aware 

 *of. 



In sub-arid Western Australia dust whirls are locally known as 



*' willy-willies." They are a matter of common knowledge, but no 



■precise description has, so far as the writer is aware, ever been 



given of them, and still less is there any record of their mode 



of rotation, their height and other characters. Even in Australia 



f. L.OC. cit. 



8. Monograph XI., U.S. Geol. Surv., Washington, 1885, pp. 9 and 154. 



9. See also Mawson's estimate mentioned below. 



10. " Spinifex and Sand," London, 1898, pp. 254 and 274. 



11. "The Dead Heart of Australia," London, 1906, pp. 26, 120, 121. 



12. " Geological Investigations i'n the Broken Hill Area," Mem. Roy. Soc. 

 ;South Aust, Vol. IL, Part 4, 1912, p. 227. 



13. •" The Significance of Some Physiographical Characteristics of Western 

 .Australia." Journ. Roy Soc. W. AUst., Vol. II., 1915-16, p. 83. 



