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7H “A. 
398. Foreign Literature and Science. 
43. Preservation from rust.—IJt bas been ascertained by 
Arthur Aikin, secretary to the Society of arts and manufac- 
tures, that melted Caoutchouc is an excellent material ior 
the above purpose. Plates of iron and steel, half covered 
with this substance, were exposed six weeks in a laboratory, 
and at the end of this time the uncovered parts were almost 
entirely corroded, while the varnished parts were complete- 
ly preserved. 
aoutchouc must be melted ina close vessel. It requires 
about the same temperature for fusion as lead. When 
melted it must be stirred by a horizontal agitator, the han- 
dle of which rises through the cover, to prevent its being 
burnt at the bottom. 
‘Mr. Perkins has perfected this process, by dissolving the 
caoutchouc in spirits of turpentine. The varnish thus ob- 
tained; after being suitably dried, becomes firm and does 
not change by exposure to moisture. It is laid on with a 
soft brush, and may be removed at any time by dipping the 
brush in hot spirits of turpentine. Mr. Perkins uses this 
varnish to preserve his engraved steel plates. 
44. Geology.—There is found in the northern provinces 
of Russia, besides the bones of the mammoth and some oth- 
er remarkable objeds of natural history, a kind of fossil 
wood, in part petrified, and in part decomposed or rotten. 
Professor Kounizin remarks that he formerly entertained 
the popular opinion that these trees had been blown down 
and gradually covered with sand and mud in or near the 
places where they grew. But he is now convinced that 
this is an error, and that they must have had an origin, 
quite remote from their present situation. For Ist. They 
are covéred to a great depth with earth, in the form of beds 
parallel to the surface. 2d. All the trees have their tops 
directed toward the same quarter, and they are only inclin- 
ed. 3d. Almost all have been broken by an irresistible 
force, the oaks alone retaining their roots. 4th. The bed 
of earth under which they are found is so thick that the wa- 
ters of the rivers do not reach them. This earth is partly 
sand and partly clay. The trees that are covered with dry 
sand are quite rotten and moulder speedily into dust. 
Those under moist sand are still in good preservation. The 
pines and firs are more decomposed than the others, but 
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