345 
among the dust found in the snow-fall of January 20, while the fila- 
ments, though less varied and interesting than those then collected, 
were quite similar in character, even to the tiny glass particles 
sprinkled upon them. 
A minor point of resemblance was that the yellow color of one 
little vesicular mass in the dust caught January 20 was fairly matched 
by a slight streak of similar color in the pumice. 
In March, 1884, I collected dust from the steel works at South 
Bethlehem, Pa., and also dust from a blast furnace there, in order 
to compare them with the dust found in the snow and with the fila- 
ments and crumbs of pumice from the ship 7. £. Ridgeway. 
After separating from these dusts the large proportion which was 
attracted by the magnet, the remnant showed in each case many 
vitreous particles ; that from the iron furnace largely spheroidal or 
globular, with a few filaments; that from the steel works partly 
minute rounded particles, but containing many filaments of great 
tenuity. Neither contained such clear vitreous plates and aggrega- 
tions as abounded in the snow-dust, while the filaments in both 
cases were of dark color, and smooth, straight form, distinctly dif- 
ferent from the colorless and frequently contorted filaments of the 
snow-dust. 
It is difficult to resist the conclusions (1) that the vitreous dust 
found in the snow-fall of January 20, 1884, was not derived from 
iron or steel furnaces, (2) that it was of similar origin to the floating 
pumice found by the ship 7. Z. Ridgeway, (3) that it was ejected 
by the huge volcanic explosions of Krakatoa. 
Den Forschern. 
Von Dr. Hermann Rollett® (Baden bet Wien). 
Welch’ frischhinwogende Bewegung hast 
Du aufgestért, die Alles rings erfasst, 
Du Wort Darwin's, das langst lag auf den Zungen, 
Doch auszusprechen Keinem war gelungen : 
Dass sich—nach Luftart, Nahrung, anderm Leben— 
Die Organismen ‘‘ anzupassen ’’ streben ; 
Dass ‘‘ Aenderungen ”’ sich dadurch gestalten, 
Die durch ‘‘ Vererbung ’’ fest sich forterhalten ; 
* Als Gruss aus der Ferne gewidmet zur glorreichen, am 22. bis 26. Mai 1893 stattfin- 
denden Jubiliumsfeier der American Philosophical Society in Philadelphia. 
PROC. AMER. PHILOS. SOC. XXXII. 143.2 R,. PRINTED MAY 28, 1894. 
