FRESH-WATER ALG. 267 
square miles. A great mass of substance remark- 
ably like paper fell during a violent storm in 1687, 
near the village of Randen in Courland, which 
excited great curiosity at the time, and was found 
after the lapse of many years, by the all penetrat- 
ing microscope of Ehrenberg, to consist of a com- 
pactly matted heap of diatoms and conferve. 
Diatoms have even been discovered in the pumice 
and ashes ejected from the burning craters of 
volcanoes. 
‘The dust we tread upon was once alive!’ was 
the exclamation of one great poet; and ‘How 
populous, how vital is the grave!’ was that of an- 
other, but little did either Byron or Young know 
how extensively true were the words they uttered. 
The microscope shows us how inconceivably popu- 
lous is the whole world, when thus the loftiest 
regions of the atmosphere, and the fathomless 
depths of the ocean, and the darkest, deepest 
abysses of the earth, where we should suppose all 
life impossible, are peopled with myriads upon 
myriads which the Infinite mind alone can enu- 
merate, of minute vegetable organisms, perform- 
ing their allotted task in the great workshop of 
nature, and adding a thousand times more to the 
mass of materials which compose the crust of the 
globe, than the bones of elephants and whales. 
To the investigation of the diatoms, we must 
