24 
Proceedings of Royal Society of Edinburgh. 
-Acting on these considerations, in the winter of 1880-81, a 
number of muds and nodules were examined with a view to the 
detection, and if possible the estimation, of free sulphur. 
Estimation of Sulphur in Muds. 
A certain quantity of the clay, dried at about 80°, was put into a 
bottle with a known weight of chloroform. The stopper was tied 
down, and it was then put into a water-bath for about an hour at 
about the temperature of boiling chloroform (61° C.). It was then 
allowed to cool, filtered into a weighed fractionating flask, and 
washed twice with a little more chloroform. The chloroform was 
then distilled off, and the residue heated slightly and weighed. 
The residue was treated with hot nitric and hydrochloric acids, 
diluted, and filtered if necessary, barium chloride solution added, 
allowed to stand, filtered, and the precipitate of barium sulphate 
weighed. 
In the first few samples the barium sulphate was not weighed, 
but the quantity of sulphur judged by the amount of barium sul- 
phate precipitated. 
At first bisulphide of carbon was used, but it was departed from, 
because, although perfectly pure, and leaving no trace of sulphur on 
evaporation, it was thought that it would be well to use a solvent not 
containing any sulphur. A portion of the blue clay from the Sound 
of Jura, which -when fresh contains much sulphide, was in the 
dried state tested w r ith both solvents, with the following results. 
Treatment with Bisulphide of Carbon . — A quantity of the clay 
was pounded and dried at about 80°. 50*00 grammes were put into 
a bottle with 236*0 grammes of bisulphide of carbon, and allowed 
to stand all night. A weighed portion of the carbon bisulphide was 
then taken out and put into a weighed flask, and the carbon 
bisulphide distilled off, and the residue weighed. 0*28 per cent, of 
sulphur was found in this way. 
The sulphur dissolved completely in a small quantity of bisul- 
phide. Next day another portion of carbon bisulphide was taken 
out and put into a weighed flask, distilled, and the residue weighed. 
This gave 0*33 per cent, of sulphur. 
The bisulphide was tested to see whether it contained any free 
sulphur ; it turned out to be very nearly pure. 
