28 Proceedings of Royal Society of Edinburgh. [sess. 
No. 15 is from a position north-east of the Island of Rum, in 
147 fathoms, soft grey mud. 
No. 16 is a blue mud, from 2050 fathoms in the Celebes Sea. 
No. 17 is a glauconitic mud from the east coast of Australia, in 
410 fathoms, lat. 34° 13' S., long. 151° 38' E. 
No. 18 is a diatomaceous mud from the Antarctic Ocean, in 1950 
fathoms, lat. 53° 55' S., long. 148° 35' E. 
No. 19 is a red clay dredged on the 13th March 1874, in 2600 
fathoms, lat. 42° 42' S., long. 134° 10' E. Along with the mud a 
large quantity of manganese nodules was brought up. 
No. 20 is a radiolarian ooze from the North Pacific, lat. 12° 40' 
N., long. 152° 1' W., depth 2900 fathoms. 
Nos. 21 and 22 are again samples of globigerina ooze from the 
Atlantic and the Pacific respectively. These samples differ from 
Nos. 12 and 13 inasmuch as the Pacific sample now contains more 
sulphur than the Atlantic one. 
No. 23 is the insoluble residue left after treating a nodule from 
the same locality as No. 2 with hydrochloric acid and ferrous 
chloride. The difference is very remarkable. In No. 2 the 
sulphur was not determined — that is, the barium sulphate produced 
by its oxidation was not weighed ; but it was one of these samples 
which showed that the amount present was so appreciable that it was 
worth while determining it as accurately as possible, so that it is 
certain that it must have contained at least an average amount. In 
the case of the natural nodule (No. 2) the weight of chloroform 
residue per 100 grammes substance was 29 milligrammes; in 
the case of the extracted nodule No. 23 it is 2 milligrammes, and 
the weight of sulphate of barium is put down as 1 decimilli- 
gramme. In fact, the sulphur in the nodule had disappeared under 
the treatment. 
No. 24 is from Loch Eyne, in 87 fathoms, opposite Otter House, 
and a little further up the loch than the station No. 6, but both of 
them in the outer loch, as opposed to No. 11, which is in the 
upper and semi-enclosed basin. The contrast between No. 24 and 
No. 11 is remarkable. In the upper basin the amount of the 
chloroform residue per 100 grms. substance was 74 milligrms., 
and 10 milligrms. of it was sulphur. In the outer loch there 
were only 17 milligrms. of residue and 1 milligrm. sulphur. 
