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whilst those to the right and to the left I assumed to he 
those of the usual prismatic order. 
Instead of a diffraction plate of ruled lines, and con- 
sequent flashing angles, we had on the lake a glassy surface 
covered totally with globules of water, each of which 
was reflecting the sun’s rays, after refracting, and dis- 
persing the light on the inner face of each lens, according 
to the position of the observer. I could detect colour in the 
globules not more than a dozen yards from the boat, and 
then, by tracing them towards the shore, could see them 
increase in number and brilliance, in consequence of what 
seemed to be the curvature of the lake, which corresponds 
with that of the earth ; and what was most extraordinary, 
I thought I could discern a movement among these glittering 
globules, which sparkled like diamonds on the bosom of the 
water, begotten not of the surface, as a wavelet, but from 
an inner force like the breathing of an animate being, a 
surging or swelling of the dark body of the lake, which 
may perhaps have been derived from tidal force, the attrac- 
tion of the moon, or from some under-current lifting the 
surface. This was observed on looking at the double 
spectrum westward. 
It appeared to me that an explanation of the phenomenon 
is to be found in the frozen mist which had filled the valley 
falling back upon the bosom of the lake with such gentle 
force as to remain unbroken by the impact, and each globule, 
enveloped in its own air-film, lay thus poised upon the 
water, receiving the light of the sun and sending it back to 
the observer in a spectrum band of prismatic colour. 
I assume that these floating globules were dew, whether 
frozen or not ; and in contradistinction to the rainbow, per- 
haps I may call this the dewhow, for by an optical illusion 
it seemed to be a bow and yet it was a straight line, or such 
a small segment of a large arc as to seem hardly other than 
a straight line. I have not been able to find that dew has 
