THE SCIENTIFIC MONTHLY. 
562 
same result that is obtained by ordinary filtration in days or even weeks. Simple 
drying restores to the infusorial earth its absorptive powers. 
4. Owing to its great volume*and slight weight, it is employed for packing 
very fragile objects and glass apparatus, etc., and mixing with plaster of Paris for 
making light casts. 
5. Owing to its fineness it is used as a cheap polish for glass and metal, and 
is an excellent material for cleaning greasy vessels and pieces of machinery. 
Scientific American. 
DISCOVERY OF HUMAN BONES . 
While some workmen were excavating some time ago, in a quarry of Jurassic 
limestone, near Belfast, in France, they discovered an opening in the hill which 
it was found led to a cave of large! dimensions. On entering the cavern, its floor 
was discovered covered with human bones, and so disposed as to lead to the belief 
that the cavern had once been used as a place of sepulchure. 
Polished flint weapons, ornaments, and other articles were found, including 
several beautiful vases, and a mat of rushes. The authorities of Belfast at once 
took possession of the cavern in the interests of science, and designated Mr. Fel 
Voulot, an archaeologist of renown, to examine the cavern and its contents. • The 
are no doubts but that these are the remains of the'polished stone age, and son 
are sanguine that further research will bring to light relics of a much older perio 
One writer in the Berne Scientific hopes to find remains belonging not only to th 
Tertiary, but even to the Crelaceons period. This cavern is situated in £ bed ( 
one of the lower strata of the Jurassic period, V on the exact limit of the shore c 
the ancient Jurassic sea.” 
« 
NEW DISCOVERY IN AGRICULTURE. 
The curious discovery is announced by Prof. P. B. Wilson, of Washington _ 
University, Baltimore, that minutely pulverized Silica is taken up in a free statq 
by plants from the soil, and that such silica % assimilated without chemical 01 
other change. The experiment consisted in fertilizing a field of wheat with the; 
iufusorial earth found near Richmond, Virginia. This earth, it is well known,' 
consists of the shells of microscopic marine insects, known as diatoms, which 
under strong magnifying powers reveal very beautiful forms that have been resolv¬ 
ed, clafsified and named. 
After the wheat was grown, Prof. Wilson treated the straw with nitric acid, 
subjected the remains to microscopic test and found therein the same kinds of 
shells or diatoms that are present in the Richmond .earth, except that the larger 
sized shells were absent; showing that only silica particles below a certain degree 
of fineness can ascend the sap pores of the plant. 
This discovery opens up a new line of research in agricultural investigation* 
from which important results and much additional knowledge may accrue, 
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