1883.] Geology and Paleontology. 1053 
Section than the awful fate Mr. Rand hints at—Persifor Frazer, 
Sea Girt, Aug., 1883. 
ATMOSPHERIC Dust AND DISEASE GERMs.—At a recent meeting 
of the San Francisco Microscopical Society Mr. H. G. Hanks 
read a paper on “Some notable features of the great San Fran- 
cisco snow storm of December 31, 1882.” 
A storm of brief duration, resulting in the fall of a few inches of 
snow, would attract but little attention should it occur in the 
Eastern or Northern States of the Union, but at San Francisco, 
where such phenomena are almost unknown, the only instance on 
record during half a lifetime naturally became the absorbing topic 
of conversation. When, however, the warm air dissipated the 
snow and the streets of the city assumed their usual appearance, 
the wonderful snowstorm was forgotten. Apart from the storm 
ing unusual and remarkable, there were certain features con- 
nected with it, both interesting and important, which, no doubt, 
escaped the notice of the casual observer, but to which my atten- 
tion was drawn by accident. While the snow was falling, to all 
appearance clean and white, the idea occurred to me that it 
afforded an opportunity to obtain, without much trouble, a stock 
of pure water for chemical purposes: With this view I melted a 
quantity in a tin vessel in my private laboratory. To my surprise 
I found the resulting water milky, a deposit or residue of a muddy 
character remaining in the can. Without at first attaching any 
importance to the circumstance, I proceeded to filter the water, 
but found the filtrate still milky. Thinking the matter over, I de- 
termined to examine the residue under the microscope, when 
found that I had in the field of the instrument finely divided sand, 
very much resembling that of the Great Colorado and Mojave 
cent microscopic investigations. With this clue I submitted 
the fine sand to a closer examination—mechanical, chemical and 
Optical. 
ber. On being calcined in a platinum dish, it at first burned, 
then blackened, and on continuing the heat to incineration, the 
While I was making these experiments a telegram appeared in 
