480 
water was about seven feet; but, owing to 
the influence of gales and currents, the whole 
ocean is filled with pack from fifty to two hun- 
dred feet in thickness. During the whole win- 
ter this region is subject to violent local gales, 
which open huge cracks in this frozen ocean, 
often extending many miles, and from ten to 
five hundred yards wide. These cracks freeze 
over very rapidly, as the temperature of the 
sea-water alway stands at 29.2° F. We have 
known two feet and a half of ice to be formed 
over one of these cracks in ten hours. This 
expansion, acting like a great wedge, shoves 
the great masses of pack apart ; and it can only 
find room in the direction of the lower latitudes, 
or side of the least resistance. Hence we see 
along the southern edge of the eternal pack a 
continual crowding-down of old ice, which has 
yielded to the new ice formed in the cracks, and, | 
in its turn, is packed and displaced; but we 
never found that there was any accumulation 
of new ice on the submerged masses of old 
pack, no matter to what depth they rested in 
the water. This process going on daily and 
hourly, the ice over the pole is kept at an even 
thickness ; the old, heavy ice, often high above 
the surface, yielding to the new. We never 
found that ice formed on the bottom of the sea, 
the lakes, or the rivers. 
The migration of the eider occurs in May ; 
and the flight is to the north-east, in the direc- 
tion of Prince Patrick’s Land. We never saw 
any flight of birds to or from true north at any 
season of the year. They commence returning 
along the western shore in July, and linger as 
long as there is any open water. 
The members of the expedition found time 
to make a large collection in ethnology and 
natural history, which has been turned over 
to the Smithsonian institution, and is now be- 
ing catalogued and placed. All records were 
kept in duplicate, and both copies were brought 
safely back to the United States. The official 
report is now being compiled at Washington, 
and will be issued by the signal-office as soon 
as published. 
The party returned to the United States on 
the schooner Leo, chartered for that purpose ; 
leaving the station Aug. 29, 1883, and re- 
turned vid Bering Strait and the Pass of 
Akutan, landing at San Francisco, Cal., Oct. 
7, 1883 ; touching only at St. Michael’s, where 
Lieut. Schwatka and his party were found wait- 
ing for a chance to return to the United States, 
after their adventurous ride of over two thou- 
sand miles down the Yukon on a raft, and at 
Unalaska, to repair our little vessel, which had 
been damaged by the ice. P. H. Ray. 
SCIENCE. 
i ied! 
’ co hes hy ' 7 v 
[Vou, III., No. 68, 
ON THE STATE OF THE INTERIOR 
OF THE EARTH. 
THE appearance of the new edition of Thom- 
son and Tait’s treatise on natural philosophy 
affords an opportunity for geologists to object 
to conclusions reached by physicists in relation 
to the condition of the interior of the earth. 
Various physicists, chief among whom are 
Hopkins, Sir William Thomson, and G. H. 
Darwin, have concluded, from a discussion of 
the phenomena of precession and of tidal fric- 
tion, that the earth is a solid, with a rigidity 
at least as great as steel. Some time ago 
Thomson retracted the first part of the argu- 
ment, on a suggestion made by Newcomb, 
and the writer expected to see a retraction of 
the entire argument in the new edition of the © 
philosophy; but it does not appear. Yet the 
statement is somewhat modified. On the 485th 
page of vol. i., part ii., the following para- 
graph appears : — 
‘¢'These conclusions, drawn solely from a 
consideration of the necessary order of cooling 
and consolidation, according to Bischof’s re- 
sult as to the relative specific gravities of solid 
and of melted rock, are in perfect accordance 
with §§ 832-848, regarding the present con- 
dition of the earth’s interior, —that it is not, 
as commonly supposed, all liquid within a thin 
solid crust of from 30 to 100 miles thick, but 
that it is, on the whole, more rigid, certainly, 
than a continuous solid globe of glass of the 
same diameter, and probably than one of steel.”’ 
It is not my purpose as a geologist to dis- 
cuss the methods by which this conclusion is 
reached ; nor shall I array the facts by which 
geologists arrive at a different conclusion. I 
propose simply to characterize the lines of in- 
ductive reasoning used by them. These are 
as follows : — 
I. The argument from displacement. 
The writer has carefully studied a fault in 
Utah and Arizona, about three hundred miles 
in length, with a throw varying from two thou- 
sand to five thousand feet. Everywhere along 
its course the displacement is easily seen: its 
verity is a fact of observation, confirmed by 
the observation of other geologists thoroughly — 
competent. The fault is so plain, that the 
tyro in geology may see it. Now, in the case 
of this fault, three hypotheses may be enter- 
tained, — first, that the thrown side subsided ; 
second, that the thrown side remained station- 
ary in relation to the centre of the earth, and 
the opposite side was upheaved ; or, third, that — 
