RED RAIN DUST. 87 



In composition and appearance this dust closely resembles that 

 which fell in Victoria in 1898, both being doubtless derived from 

 the dry interior of the continent. Neither of these dusts contained 

 any magnetic particles. 



An analysis of the Sydney dust by Mr. L. Cohen, published in 

 the Sydney Daily Telegraph newspaper, Nov. 1st, 1909, shows the 

 very large proportion of 14" 69 (when calculated to dryness) of ferric 

 oxide, no ferrous oxide, and considerably less alumina than I find 

 to be present in my sample. So great a proportion of iron oxide 

 may perhaps be due to contamination with rust from the iron roof 

 on which Mr. Cohen's sample was collected. 



A rough idea of the amount of dust which fell may be gathered 

 from the weight collected by me from one of the skylight windows. 

 To all appearances the greater part of the dust which fell on the 

 window remained adhering to the edge of the glass, though pro- 

 bably some was washed away. The window in question had an 

 area of about 68 square feet, and the weight of air-dried dust 

 collected therefrom was about 6 grams. This is equivalent to 

 about 8 J lb. per acre, or nearly 2 J tons per square mile. 



Leaves of trees and various plants were coated with the dust, 

 which collected along the veins and edges in such situations as 

 would retain adhering water. As the water evaporated, the dust 

 remained and was in evidence for several days until washed off by 

 subsequent rain. Although the dust is spoken of as red, it is really 

 of a pale buff or clay colour, which becomes somewhat red on 

 moistening. 



Some time after the publication of my paper on the Victorian 

 dust of 1896, Dr. T. L. Phipson, of London, published two papers 

 detailing the results of his examination of a small sample from the 

 same fall, given to him by Captain C. J. Gray, who personally 

 collected it.^ Dr. Phipson claims to have detected nickel in the 

 dust, which he estimates at about 1 per cent., and in his first paper 

 he concludes that "it is partly, if not wholly, of cosmic origin, and 

 not merely desert sand uplifted by the wind, nor volcanic dust ; it 

 would appear to be the mineral dust left in the higher regions of the 

 air by the explosion of meteors or shooting stars." In his second 

 paper, however, after examining a further sample weighing about 

 half a gram, given him by Captain Gray, Dr. Phipson altogether 

 ignores his first conclusion, and says : " I am decidedly of opinion, 

 after due discussion of this subject, that this dust brought down in 

 the rain is of volcanic origin." 



Working on much larger quantities than Dr. Phipson had at 

 his disposal I have been unable, by ordinary chemical tests, to 

 confirm his detection of nickel, the presence of which, in any case, 

 is by no means a reliable indication of cosmic origin. I see 

 nothing in the character of the dust or in the circumstances 

 attending its fall to lead to any other conclusion than that it 

 consists of ordinary soil, raised and carried by wind from the in- 

 terior of Australia. 



(1) Chemical NeK's., Ixxxiii., pp. 159, 253. 1901. 



