172 
HYDROGHAPHICAL NOTES. 
served this shining appearance very strongly, which in- 
duced me to draw a bucket of water, for the purpose of 
examining it. I had it suspended so as to have as little 
motion as possible ; when this was the case, it shone very 
little ; but the moment it was disturbed, it shone with great 
beauty. I next got a little lime-juice, and put a wine-glass 
full of this acid into the bucket, when the shining particles 
began to move about in all directions, sometimes going only 
as far as the middle of the bucket, then turning and taking 
a zig-zag direction. These motions certainly had every 
appearance of the depending upon the will of an animal : 
they shone with much splendour, and some appeared as 
large as the tip of one's finger. Another glass of lime-juice 
instantly destroyed them; for, at the instant the second 
quantity was poured in, the water appeared to be one blaze 
of fire, and no motion or disturbance could make it shine 
after this. 
I then drew some more water up, which shone as before ; 
part of this I kept during the night in an open vessel, and 
part tightly corked up in a bottle ; and the next night, on 
examining these two portions, I found that the water in 
the open vessel shone pretty brightly, but not so bright as 
it did ; and that which had been corked up did not shine 
in the least, the want of air seeming to have killed the ani- 
mals. They appear to me to be coated with some phos- 
phorescent matter ; for one of them I happened to rub upon 
my fore-finger, which left a streak of light for a few seconds, 
as long as the first joint of my finger. Now, when the fire- 
fly, or the glow-worm, are killed, their light is immediately 
e^jLtinguished. 
