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Art; V. — Account of some Eacperiments, made with the view 
of ascertaining the different substances from which Iodine 
can be procured. By Andrew Fyfe, M. D., Lecturer on 
Chemistry. Communicated by the Author. 
Sir Humphry Davy, in one of his early papers on Iodine^ 
published in the Philosophical Transactions for 1814, mentions^ 
that he had procured this SLibstance from the 
Fucus cartilagineus. Fucus filiformis. 
membranaceus. Ulva pavonia. 
rubens. linza. 
He did not, however, obtain k from the alkaline matter manu- 
factured at Sicily, Spain, and the Roman States, nor did coral 
and the ashes of the sponge seem to contain it. 
Shortly after the publication of this paper, I commenced a 
series of experiments, to ascertain the different substances from 
which iodine could be obtained. 
An account of these was read before the Royal Medical So- 
ciety of this place, in the winter of 1815. Since then I have 
bad several opportunities of subjecting other substances to 
analysis, with the view of ascertaining if they would yield io- 
dine. 
I may here remark, that at the time when most of these expe- 
riments were made, it was not known that starch proved a deli- 
cate test of the presence of iodine. I had therefore recourse to 
that of silver, as pointed out by Sir H. Davy, when the vapour 
of iodine did not appear, on the addition of sulphuric acid to 
the saline substance. 
The first object in these experiments, was to ascertain the 
different marine plants from which iodine could be obtained. 
For this purpose I procured quantities of all the common kinds of 
sea- weed growing on the shores of Leith. These were dried by a 
gentle heat, and then burned, either in a large crucible, or in a 
chaffer; the temperature never being so high as to cause the 
fusion of the substances. The product of the combustion was 
then dissolved in water, and the solution was evaporated to dry- 
ness, Sulphuric acid was added to the residue in a glass tube, 
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