210 H. A. Hazen—The Sun Glows. 
must be turned to different points in the sky. However this 
may be it would seem that the presence of an abundance of 
frost particles would not affect the spectrum as would the same 
‘amount of aqueous vapor above a temperature of 32°. d 
A most singular hypothesis has been advanced to account 
for the material in the sky, namely, that the volcanic action at 
Krakatoa on Aug. 26th and 27th ejected, into the atmosphere, 
immense masses of ashes which have been distributed by air eur- 
rents over the earth’s surface. Vivid accounts of the terrific 
nature of this convulsion, whereby a mountain island 2000 feet 
in height was perceptibly lowered, have been published phy: 
12 
witnesses. The position of the volcano was in lat. 6 .) 
28’ 
3d. The upper currents must have had sufficient velocity t0 
carry the ashes a distance of 12,000’miles in 150 hours or at & 
rate of 80 miles per hour toward the west. We know little of 
velocities of air-currents at great heights, but they are probably 
slight. The summer velocity on Mt. Washington, 6299 feet 
too high, but, allowing for these, there seems to be a possl- 
. . 7 s sé * ne r. 
bility of a gradual diminution in wind velocity at increasing — 
heights above the earth’s surface. 
4th. 
at the ashes must have been mechanically dist 
uted first along a belt near the equator, and afterward, withoub 
addition except possibly of a meager character, the cu 
h 
must have been sufficiently uniform over the whole earth, 
: RO 
m fiorth and south to above iatitade 
rne. the - « few 
This is well nigh incredible. It seems probable that in a 1eW 
rrents | : 
