OROGENY AND EARTH’S ROTATION 
55 
By the newer experimentation the mechanical principles in¬ 
volved are capable of mathematical expression; which is not pos¬ 
sible with the older performances. 
Ever since the Swedish naturalist Hjarne published the results 
of the first direct observations on the relative changes of sea-level 
on the shores of his homeland, more than 200 years ago, the os¬ 
cillations of the strand-line have been almost universally regarded 
as conclusive evidence of local land elevation and depression. 
The concensus of opinion has been that the Scandinavian pen¬ 
insula, is actually rising. 
The recently expressed claim that the location of old shore-lines 
high above the present level of the sea indicates not a real but only 
an apparent uprising of the land is not new. Startling as this 
statement seems today Suess merely falls back upon that very 
old view which the Swedish astronomer Andreas Celsius set forth 
in 1743. The two views differ only in detail. The earlier writer 
regards the oceans as actually diminishing in volume at a rate of 
about half an inch a year; while the later exponent considers the 
waters of the sea as retreating into the deeper depressions of the 
earth’s crust because of the unequal secular contraction of the 
nucleus. 
Objections urged by the Scottish mathematician, John Play¬ 
fair, to the Celsius hypothesis hold today with equal force against 
the idea of Suess. In substance it is that if such a general dimin¬ 
ution of the volume of the ocean were to take place there would 
be an uniform lowering of the sea-level throughout the world; 
but such apparently is not the fact. As yet Suess seems unable 
to meet this argument; and his failure to do so is as significant as 
was that similar failure of Celsius more than a century before. 
Suess’ contention is manifestly a necessary consequence of his 
contractional hypothesis, rather than a direct evaluation of critical 
observations. The arguments which he brings up in support are 
by no means so convincing as they should be. The consensus of 
opinion among geologists appears to be that elevation and depres¬ 
sion of the land does actually take place; and the latest theory, 
that of isostasy, argues solely for vertical movement with an as¬ 
sumption that the areas now above sea-level are land tracts 
simply because, being lighter prisms of the earth’s crust, they are 
floated. 
