DECEMBER 1, 1899. ] 
five miles beneath the oceans. The present 
condition of the earth’s crust might be 
brought about by the disintegration of a 
quantity of quartz-free volcanic rock, cover- 
ing the continental areas to a depth of eight- 
een miles, and the re-formation of rocks 
out of the disintegrated materials. 
When the lighter and more bulky sub- 
stances have accumulated there has been 
a ‘relative increase of volume, and in con- 
sequence bulging has taken place at the 
surface over the continental areas. Where 
the denser materials have been laid down 
there has been flattening, and in conse- 
quence a depression of the abysmal regions 
of the ocean-basins. It is known that, asa 
general rule, where large masses of sedi- 
ment have been deposited, their deposition 
has been accompanied by a depression of 
the area. On the other hand, where broad 
mountain platforms have been subjected to 
extensive erosion, the loss of altitude by 
denudation has been made good by a rise 
of the platform. This points to a move- 
ment of matter on to the continental 
areas. 
If this be anything like a true concep- 
tion of the interactions that are taking 
place between the various geospheres of 
which our globe is made up, then we can 
understand why, in the gradual evolution 
of the surface features, the average level of 
the continental plains now stands perma- 
nently about three miles above the average 
level of those plains which form the floor of 
the deep ocean basins. We may also un- 
derstand how the defect of mass under the 
continents and an excess of mass under the 
oceans have been brought about, as well as 
deficiency of mass under mountains and 
excess of mass under plains. Even the 
local anomalies indicated by the plumb-line, 
gravity, and magnetic observations may in 
this way receive a rational explanation. 
It has been urged that an enormous time 
—greater even than what is demanded by 
SCIENCE. 
799 
Darwin—would be necessary for an evolu- 
tion of the existing surface features on 
these lines. I do not think so. Indeed, in 
all that relates to geological time I agree, 
generally speaking, with the physicists 
rather than with the biologists and geolo- 
gists. 
Progress of Oceanic Research. 
I have now touched on some of the prob- 
lems and speculations suggested by recent 
deep-sea explorations; and there are many 
others, equally attractive, to which no ref- 
erence has been made. It is abundantly 
evident that, for the satisfactory explana- 
tion of many marine phenomena, further 
observations and explorations are neces- 
sary. Happily there is no sign that the in- 
terest in oceanographical work has in any 
way slackened. On the contrary, the num- 
ber of scientific men and ships engaged in 
the study of the ocean is rapidly increasing. 
Among all civilized peoples and in all quar- 
ters of the globe the economic importance 
of many of the problems that await solution 
is clearly recognized. 
We have every reason to be proud of the 
work continually carried on by the officers 
and ships attached to the Hydrographic 
Department of the British Navy. They 
have surveyed coasts in all parts of the 
world for the purposes of navigation, and 
within the past few years have greatly en- 
larged our knowledge of the sea-bed and 
deeper waters over wide stretches of the 
Pacific and other oceans. The samples of 
the bottom which are procured, being al- 
ways carefully preserved by the officers, 
have enabled very definite notions to be 
formed as to the geographical and bathy- 
metrical distribution of marine deposits. 
The ships belonging to the various Brit- 
ish Telegraph Cable Companies have done 
most excellent work in this as well as in 
other directions. Even during the present 
year Mr. R. E. Peake has in the s.s. Brit- 
