248 
Proceedings of the Royal Society 
oxide of manganese. In about thirteen out of nearly four hundred 
soundings we did not get any information of a reliable nature about 
the deposit. 
The dredge in use was a heavy modification of Ball’s naturalists’ 
dredge, and the trawl was the ordinary beam trawl of the fishermen. 
Both of these instruments had generally a bag of canvas or other 
coarse cloth sewed into the bottom of the netting, to prevent the 
soft clay or ooze from being entirely washed out. In this way we, 
at many stations, got, along with animals, a large quantity of 
ooze, clay, stones, or manganese nodules. 
While trawling or dredging the ship often shifted her position a 
mile or two, but we could not tell whether the dredge or trawl had 
been working over all that distance, or had merely taken a dip 
into the deposits. This should be remembered when comparing 
the captures in one locality with those of another. 
Altogether there is much uncertainty about the behaviour of the 
trawl and dredge in deep water. It occasionally happened that 
when the greatest care was taken, and when it was believed that 
the trawl had been dragging for some hours, it came up without 
anything in it, or any evidence upon it or in the attached tow-nets 
to show that it had been on the bottom. 
During the last year of the cruise a tow-net was attached to the 
dredging line just below the weights, which last were placed a few 
hundred fathoms in front of the trawl or dredge. Tow-nets were 
also attached to the trawl and dredge. These nets frequently 
came up nearly full of mud, and almost always contained minute 
things and fragments from the surface layers of the bottom. 
At times the water-bottle attached to the sounding line came up 
with clay or ooze in it, or had some of the deposit adhering to its 
under- surface. 
These then were the means and methods employed for getting 
information concerning ocean deposits, and collectively they have 
furnished us with a large amount of material. A careful examina- 
tion of the specimens procured has already much increased our 
knowledge of the nature and distribution of ocean deposits, of the 
sources of the materials of which they are built up, and of the 
chemical processes taking place in the deep waters and on the floor 
of the ocean. 
