SUPERIOR ANIMALS. 159 
instrument imagined by Francois Arago. Now, in 
the case of the phosphorescence of Schistotega os- 
mundacea, spoken of in the second part of this 
work, and those cases alluded to here, it would be 
easy to ascertain whether the hght was transmitted 
directly from the plant or the animal itself, or owed 
to the reflection of diffused daylight, as we observe 
on the spiders’-webs in a semi-obscurity. Very 
simple polariscopes, consisting of plates of crystal 
mserted into flat pieces of cork, are sold by some 
of the opticians of Paris ; whenever reflected light 
is observed, at certain incidences, through this 
simple apparatus, it shows coloured stripes, owing 
to the polarization of the reflected ight. With 
directly transmitted heght these coloured bands 
are not visible. 
A very remarkable case of phosphorescence was 
witnessed by Dr. Kane in his last voyage to the 
Polar regions, and described in his journal under 
the date January 2nd, 1854. He was on his way 
with Petersen to an Esquimaux settlement, in 
order to procure food. Their thermometer was 
at —42° Centigrade (—44° Fahr.). With their 
weary dogs and sledge they had reached some un- 
tenanted huts at a place called Anoatok, after 
thirty miles’ march from the ship :—“ We took to 
the best hut,’ says Dr. Kane, “ filled in its broken 
front with snow, housed our dogs, and crawled in 
among them. It was too cold to sleep. Next 
