842 REPORT—1868. 
in 189 fathoms, and also a fragment sent to me to examine by Mr. 
D. Robertson, who procured it from Faroe, which exactly correspond 
with Fleming’s brief description ; and as the specimens which I haye seen 
are from the north and from the south of Shetland, there is eyery like- 
lihood of its haying been found at the intermediate locality. A de- 
scription of the species will be given by me in the Report of the Inyer- 
tebrata procured in the ‘ Lightning’ expedition. 
Report on the Chemical Nature of Cast Fron.—Part I. Account of 
some Experiments made to obtain Iron free from Sulphur. By A. 
Marrutrssen, /.R.S., and 8. Prus SzczEPaNowsk1. 
Forxiowrne out the plan indicated in the preliminary report presented to the 
Association in the year 1866, we have been endeavouring to prepare pure 
iron, but have encountered greater difficulties than we expected, owing to 
the great affinity which iron has for sulphur. Although we have not been 
able as yet to prepare iron absolutely free from sulphur, yet the results, as 
far as they have been obtained, may be of interest to the Association, and 
a brief account of them is given in the following pages. 
In the endeavour to prepare pure iron, we always found sulphuretted 
hydrogen on dissolving the metal in dilute hydrochloric acid. The small 
quantity of sulphur contained in the iron did not proceed from the hydrogen 
or from the platinum-tube in which the oxide was reduced. The manner of 
preparing the pure hydrogen and the precautions taken with the platinum- 
tube will be described hereafter. 
The first series of experiments were made by precipitating the hot, concen- 
trated, clear solution of protosulphate of iron by oxalate of ammonium, washing 
the precipitate till the wash-waters no longer indicated sulphuric acid with 
chloride of barium, heating the dried oxalate of iron to redness in a platinum- 
dish, and reducing the oxide thus obtained in a platinum-tube. The reduced 
iron contained sulphur. In all the experiments we describe sulphur was 
tested in the following manner. The iron was placed in a test-tube with some 
dilute pure hydrochloric acid, and the gases were allowed to pass through a 
small tube fitted into a cork in the test-tube, and to impinge on a paper 
moistened with acetate of lead. The evolution of sulphuretted hydrogen, after 
a very little experience, moreover is just as easily detected by the smell. 
Experiments were also made with the oxalate of iron by redissolving it in 
hydrochloric acid and reprecipitating with ammonia, or by dissolving the oxide 
obtained by heating the oxalate of iron in hydrochloric acid, and reprecipi- 
tating again by oxalate of ammonium. Im all these cases the reduced iron 
contained sulphur. 
The second series of experiments were with iron obtained from the crystal- 
line oxide. It is well known that when protosulphate of iron is fused with 
chloride of sodium, a crystalline oxide is obtained. For our experiments it 
was of course necessary to perform this operation in a platinum crucible, 
but it was found that the iron thus obtained contained a small quantity of 
platinum. We therefore employed instead of chloride of sodium the sulphate 
of sodium, and obtained an oxide which, after being thoroughly washed and 
reduced, gave an iron containing no platinum but still traces of sulphur. 
Experiments were then made by dissolving the crystalline oxide in pure 
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