THE PEACOCK BUTTERFLY. 127 
recorded, but erroneously investigated, as related in 
Roman history, prior to the birth of Christ. Dio 
Cassius, in particular, considered, that the blood rain 
which fell in Egypt in the time of Octavian, must 
be recorded as a thing very remarkable, because it 
never rained in Egypt. This however is a mistake. 
We are told that, in the year a. p. 65, during the 
reign of Nero, blood rain fell, which tinged the rivers 
with a red colour. Two other instances are record- 
ed in the tenth century ; one in the eleventh ; two 
in the twelfth; one in the thirteenth ; two in the 
fourteenth ; one in the fifteenth; and five in the 
sixteenth. 
The circumstances under which these isolated 
incidents happened, are not related,—whether these 
showers fell from clouds, or whether there were an 
abundance of clouds in the atmosphere at the time ; 
nor are we informed if these red showers were 
actually seen falling, or whether they were merely 
observed on the ground, and hence concluded to be 
drops of red rain which had fallen. These accounts 
have, for the most part, been accompanied with such 
superstitious notions, and additions so manifestly 
false, that we venture to account for them by phe- 
nomena within the reach of physical science. 
It is no new discovery that insects are the cause 
of showers of blood ; for Sleidan mentions, that, in 
the year 1553, a great part of Germany swarmed 
with immense multitudes of butterflies, and that 
