2 
CBUISF OF H.M.S. CHALLFNGEB. 
the sea, the shape and character of its bed, the 
nature of the creatures and plants that haunt its 
depths, the force and set of its currents, the figure 
and dimensions of the great ocean basins, and the 
temperature of the water at various depths. 
Interesting as were the results of the various early 
sounding expeditions, it was not until 1868 that any- 
thing like a systematic examination of the ocean's 
bed was undertaken in connection with natural 
history and physical geography. In that year the 
Royal Society succeeded in getting H.M.S. Lightning 
placed at their disposal for some six weeks ; and 
though for so brief a period, the results were such as 
to give great encouragement for further investiga- 
tion. Although no great depth of water was obtained 
in sounding, dredging was effected in 650 fathoms, 
a greater depth than had hitherto been attempted. 
The next year (1869) the Council of the Royal 
Society were successful in securing H.M.S. Porcupine , 
which was fitted out for a more extended explora- 
tion of the deep sea ; and the experience of the pre- 
vious year was brought to bear on the improvement 
of the means for the purpose in view. 
The first cruise was between the latitudes of Cape 
Clear and Gfalway, on the west coast of Ireland, where 
a series of soundings and dredgings w^ere effected in 
1500 fathoms (more than double that of the previous 
year), and many creatures of great interest obtained. 
The second part of this cruise extended to the 
