THE VICTORIAN NATURALIST. 19 



rain was pre-eminently brought under notice by the elaborate 

 work of Dr. Ehrenberg, published in 1847.* That author gave a 

 detailed account of the falls of blood-rain or sirocco dust at Genoa, 

 Lyons, and elsewhere, and of the "sea dust" collected near the 

 Cape Verde Islands by Darwin and Lyell ; all of these contained 

 many species of diatoms, chiefly of freshwater habitat. Ehren- 

 berg also recorded the contents of sediment from a " red snow 

 fall" in the Tyrol, which appears to be of the nature of red dust, 

 in which he found numerous diatoms, sponge spicules, some 

 doubtful forms of foraminifera, pollen of Pinus and spores of 

 ferns, vegetable fibres and hairs, and fragments of insects. There 

 is also in this work an historical record of falls of red rain, 

 amounting in all to 340, up to the date of the publication of 

 Ehrenberg's memoir. In addition to silicious particles in the 

 sediment there will naturally be a variable quantity of desic- 

 cated material derived directly from the soil, the result of the 

 decomposition of basalt and other rocks lying in the track of the 

 wind. 



To take one or two recent instances of red rain falling in the 

 Mediterranean area, we may refer to Prof. Judd's examination! 

 of some sediment collected by Prof Sir A. W. Riicker, at Taor- 

 mina, Sicily, which fell during March, 1901, and was noticed as 

 far north as Hamburg. This material, Prof. Judd says, con- 

 tained " chips of quartz, micaceous and other minerals. A few 

 diatom frustules, but these were not so common as in that which 

 was examined by Ehrenberg in 1S47." 



Referring to the same series of showers, M. Stainslaus Meunier J 

 gave the composition of red rain which fell in Palermo on the 

 night of the 9th to loth of March, 1901, as follows: — 



In 100 parts of powder — 



Water ... ... ... ... 5.20 



Organic matter ... ... ... 3.17 



Sand .. ... ... ... 59.I4 



Carbonate of lime ... ... ... 23.91 



And by difference — clay ... ... 8. 58 



The sand referred to would be chiefly silicious ; its per- 

 centage is curiously identical with that determined for Victoria by 

 Mr. Walpole (see p. 29). 



An analysis by M. Barac of red rain sediment which fell at 

 Fiume, Hungary,§ shows a great variety of substances to be 

 present, which were due to local conditions. The presence of 



■' " Passatslaub und Blutrcgcn," Abhancllangen K. Akad. Wiss. Berlin, 

 pp. 269-460, 6 plates. 



t Nature, 28th March, 1901, vol. l.xiii., p. 514. 

 X Nature, iSth April, 1901, vol. Ixiii., p. 604. 

 § IbuL, 1901, vol. l.Niv., p. 4S9. 



