Tue Microscope. 155 
Some of the snow sediment was given to different observ- 
ers, with no hint as to its character or origin. They called it vol- 
canic dust. Thus we were gradually forced to the belief in the 
voleanic origin of the specimens. 
In order to pursue the matter further, samples were secured 
on the Atlantic coast from snow falling with the wind from the 
east, which would presumably give snow free from dust and 
sediment, having drifted in from air over the ocean. Sediment 
was also received from Utah snow. All these presented an ap- 
appearance identical with that obtained in Missouri. <A little 
later it was compared with volcanic matter from Vesuvius, and 
a striking similarity was at once apparent. The question nat- 
urally arises whence came this strange visitor? Is it cosmic or 
meteoric dust which the earth in its orbit has encountered? In 
former years observers have collected, in uninhabited countries, 
quantities of dust which was considered meteoric, and is de- 
scribed as ‘‘ little rounded particles of metallic compounds, un- 
like anything the earth is known to produce, and strikingly like 
what meteors of that size would be.” That is decidedly unlike 
the snow sediment. 
For another reason this snow sand could scarce be cosmic 
dust ejected from some planet, as such action could not be vig- 
orous enough to throw such minute particles beyond the attrac- 
tion of the place of their origin; particles so small, no matter 
how forcibly ejected, could not escape the attraction of gravity 
forcing them back to their home. 
It will be remembered that on August 26th, 1883, one of 
the most tremendous convulsions known to history wrought im- 
mense havoc in Java. Large tracts of country were wrecked, 
and from Krakatoa tons upon tons of volcanic dust, to say noth- 
ing of more bulky material, were ejected with inconceivable 
force, which coupled with the mighty up-draugh of the eruption 
must have carried the fine particles almost to the confines of 
our atmosphere. Having once attained a great altitude, borne 
by the ever-present air-currents, they would drift for months, 
and in a comparatively short time encircle the earth, and if 
they were of the same electrical sign as the earth, for instance, 
both electro negative, the repellant action of this subtle agent 
