4 
8 THE AMERICAN MONTHLY edie 
at one end and pcssessing scattered, secondary blunt 
spines. The exact nature of these last is to me uncertain; 
they may be sponge spicules, or siliceous plant hairs. 
The diatoms were generally too much fragmented for 
certain identification, a minute Surirella and a species of 
Fragilaria alone being entire. The central portion of 
what is clearly a Stauroneis, and bits of Epithemia valves 
were, however, distinguishable by their markings. 
The dust itself is pretty certainly a ferruginous clay, 
and no effervescence or visible effect was produced by 
acids. The few inorganic inclusions are minute greenish . 
grains of (?) chlorite or (?) glauconite; but these, of 
course, may be quite adventitious, 
In the absence of any knowledge of the geological fea- 
tures of the Melbourne district it is impossible to say 
whether the material is of local origin or not. In any 
case both it and its included remains are almost ubiquit- 
ous; the diatoms, etc., may have been rolled about for 
centuries or aeons. Reduced to impalpable powder by 
sun, rain, and wind, it has, perhaps, been borne aloft by 
some violent storm and travelled round the world; or, 
on the other hand, it may have been deposited by the © 
first shower not very far from its birthplace.  .- 
The phenomenon, while hardly common, is yet not of 
very infrequent occurrence. This very year it has ap- 
peared in Southern Italy and other places, and, of course, 
given rise to numerous communications to the news- 
papers. The first really scientific exposition of the causes 
of this startling phenomenon, was Prof. C. G. Ehren- 
berg’s work entitled ‘‘Passat Staub und Blut-Regen. Hin 
grosses organisches unsichtbares Wirken und Leben in 
der Atmosphaere. Mit 6 colorirten Kupfertafeln,”’ pub- 
lished in the Abh. Berliner Akad., Berlin, 1849,and other 
communications on the subject submitted to and pub- 
lished by the same Academy in 1862, and later. 
The two most common origins of so-called Blood-rain 
