26 Proceedings of Royal Society of Edinburgh. [sess. 
Treatment with Chloroform . — Another 50 - 00 grammes of clay 
were treated with 183 ’6 grammes of chloroform. The mixture was 
heated for an hour oil the water-bath at about the temperature of 
boiling chloroform (61° C.). A portion of the chloroform was then 
taken out, evaporated, and the residue weighed. This gave 039 
per cent, of sulphur. 
There was very little oil present in the residue, which was nearly 
pure sulphur. 
In the first ten samples the BaS0 4 was not weighed, hut the residue 
was always oxidised and the presence of sulphur proved by the 
formation of sulphuric acid. When sulphur was found constantly 
and in appreciable quantity, I then decided to weigh it, the opera- 
tion being, from an analytical point of view, an advantageous one, 
as the sulphate of barium weighed weighs seven times more than 
the sulphur to he estimated. By far the largest amount of sulphur 
is contained in the clay from the Sound of Jura, which, in its fresh 
state, contained large quantities of sulphides, which were completely 
oxidised on drying. TheO'197 grammes of residue may be taken 
to be pure sulphur, which makes about 0‘4 per cent. By far the 
greater part, if not the whole, of this sulphur was formed by oxida- 
tion during drying. Had it been possible to collect and examine 
separate^ the reddish-brown surface layer, we should, no doubt, have 
found very much less sulphur, but it would have been mainly due 
to oxidation by the oxygen of the bottom water. 
The “ oil,” which is extracted from all the muds along with 
the sulphur, and which varies a good deal in quantity, is due to 
the animal debris intimately mixed with the mud and with the 
materials of the nodules, which are made up, for the most part, of 
the materials of the bottom. 
Nos. 2 and 3. — The manganese nodules of the 12th July 1875, 
from the North Pacific, in lat. 37° 52' N., long 160° 17' W., came 
from a depth of 2740 fathoms, where they appear to have been 
exceptionally abundant. Those of the 16th September 1875 came 
from a locality where they were equally abundant. The water was 
a little shallower, being 2350 fathoms, in lat. 13° 28' S., long. 149° 
30' W. In both the samples of these nodules examined, the weight 
of the residue is considerable, hut as there was a little oil in both 
cases it is not possible to give the percentage of sulphur. 
