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_ XCVIIL. Proceedings of Learned Societies. 
ROYAL SOCIETY. 
June 9-and 16. A LONG and interesting paper, by Sir Humphry 
Davy, was read, detailing this philosopher’s experiments in Italy, 
on the combinations of iodine with the alkalis, potassium, so- 
dium, hydrogen, &e. 
June 23. Another paper by Sir H. Davy, sent from Rome, 
-was read, containing an account of his experiments on diamonds 
and carbonaceous matter, performed at Florence and Rome with 
burning lenses. Sir H. having conjectured ia his third Bakerian 
Lecture that the diamond owes its peculiar characters to a small 
portion of oxygen, availed himself of an opportunity while at 
Florence to operate on this substance with a very powerful lens 
and the concentrated rays of the sun, instead of the Voltaic_pile. 
He made a variety of experiments on the combustion of small 
diamonds laid in a platina cup and placed in a glass globe, 
through which the solar rays were made to pass and burn the 
diamonds; but in none of them was there any oxygen evolved: 
whence he was induced-to abanden the idea of oxygen forming 
any part of the diamond. He next directed his attention to as- 
certain whether, according to the opinion of Guyten Morveau, 
hydrogen or water might not exist in diamond; but the result 
was similar, no trace of either appearing. Moisture, indeed, in 
his first experiments was discovered; but it was entirely owing 
to an imperfection in the apparatus, which was afterwards re- 
medied.s Charcoal was then submitted to similar experiments, 
and emitted some hydrogen. Hence Sir H. concludes that dia- 
mond is perfectly pure carbon, and that its hardness and trans- 
-parency are derived from its erystallization, and not from the 
admixture of any other elementary hody. 
Sir H. has examined six different species of sea-weed on the 
coast of the Mediterranean, without finding any iodine in them, 
except some very slight traces. He also suggested some improved 
methods of detecting this singular substance ; and described a 
number of its combinations and appearances with muriatic and 
other acids, as well as with hydrogen and the gases. 
Smithson Tenant, Esq. furnished a paper giving a description 
of a cheap and easy “method of preparing potassium in consider- 
able quantities. The author, after mentioning the different 
methods hitherto adopted to prepare this metal, stated his own, 
which consists in an improvement of Gay-Lussac’s application of 
a gun-barrel. Instead of having a peculiar furnace and different 
gun-barrels, he merely takes two iron tubes, one considerably 
wider than the other; the wide one is filled with iron filings and 
potash, 
