284 
GREENLAND VOYAGE. 
the supposition of a considerable part of the light 
falling, after one refraction, on a second particle; 
so as to double the effect. “ If,” as Dr Young 
further suggests, “ the prisms he so short as to form 
triangular plates, these plates, in falling through 
the air, will tend to assume a vertical direction, 
and a much greater number of them will he in 
this situation than in any other. The reflection 
from their flat surfaces, will consequently produce 
a horizontal circle of equal height with the sun; 
and their refraction will exhibit a bright parhe¬ 
lion immediately over the sun, with an appear¬ 
ance of wings or horns, diverging upwards from 
the parhelion.” 
I state these opinions of Dr Young, on the 
cause of phenomena, nearly allied to the anthelia 
and corona;, that have now been described, both 
because they may serve, perhaps, to explain the 
origin of the second and third crowns, and be¬ 
cause they are opinions that receive considerable 
support from the circumstance of snow, of a pyra¬ 
midal, lamellar, and prismatic form, being fre¬ 
quently seen in the Arctic Regions, where the 
phenomena of haloes and parhelia are particularly 
common. On a recent voyage, indeed, to the 
coast of Greenland, two parhelia, and a horizon¬ 
tal band of white light, were observed at a time, 
when snow of a prismatic form, among many other 
figures, was seen falling. 
