162 FIRST FORMS OF VEGETATION. 
than to any other substance with which I am 
acquainted; while the singular circumstances 
connected with the history ofthis lichen, as re- 
lated from time to time by trustworthy witnesses, 
renders the supposition of its identity with the 
manna of the Israelites still more plausible. 
Showers of this lichen have sometimes fallen 
several inches thick, having been torn from the 
spots where it grew, and transported by violent 
gusts of wind. In 1829, during the war between 
Persia and Russia, there was a great famine in 
Oroomiah, south-west of the Caspian Sea. One 
day, during a violent wind, the surface of the 
country was covered with a lichen, which fell 
from the sky in showers. The sheep immediately 
attacked and devoured it eagerly, which sug- 
gested to the inhabitants the idea of reducing 
it to flour, and making bread of it, which was 
found to be palatable and nourishing. The 
people affirmed that they had never seen this 
lichen before or after that time. During the 
siege of Herat, more recently, the papers men- 
tioned a hail of manna which fell upon the city, 
and served as food for the inhabitants. <A rain 
of manna occurred so late as April 1846, in the 
government of Wilna, and formed a layer upon 
the ground three or four inches in thickness. It 
was of a greyish-white colour, rather hard, 
