116 H. W. Pearson—Changes in the Sea-Level. 
being similarly affected everywhere. It is certain, therefore, that the 
changes we have described above, being in different directions in 
different places, must be due to movements of the solid crust.” 
It seems that the conclusion above reached, based upon an argument. 
first advanced about a century since, yet remains unchallenged. The 
position assumed, at first glance, appears logical, plausible, and 
unassailable. Nevertheless, there are certain considerations arising 
from facts of recent development that should induce us to examine 
this problem anew. 
It will be seen that the entire weight of the above-mentioned 
argument is contained in the assumption—‘‘It is absurd to assume 
a rise of the sea-level in one place and a fall in another at the same 
time’? (Huxley, Physiography, p. 211); and if we find this position 
to be in error the long-adopted principle of Playfair must be held no 
longer tenable. 
In opening this question anew, let us first give consideration to 
Mr. William Ferrel’s law of deformation of sea-levels by ocean 
currents, contained in Scvence, vol. vii, p. 76. In this paper it is 
shown that oceanic currents impinging’ upon a shore-line have 
a tendency to elevate, those flowing away from a shore-line have a 
tendency to depress, the surface-level of the adjoining waters. <A table 
is also given by which the amount of this deformation in any given 
latitude may be determined when the rate and direction of flow are 
known. By application of this table, and with the most conservative 
estimate that the Gulf Stream is flowing poleward at the rate of but 
four miles in twenty-four hours, Ferrel shows that the waters 
adjoining New York would be depressed about 5 feet below, and the 
waters adjoining Liverpool elevated 5 feet above, the normal sea-level, 
through the disturbing effect of the waters’ flow. This total difference 
of 10 feet in elevation, however, he estimates will be cut down about, 
one-half from the effects of under-currents impelled by the differing, 
hydraulic heads above mentioned. His net result, therefore, is to find 
the waters around France and the British Islands elevated some 2% feet 
above, and those around New York depressed some 23 feet below, the 
normal level of the sea. 
The values above reached, however, seem much smaller than the 
actual current velocities will warrant. Data from the papers and. 
charts of the U.S. Hydrographic Office and the English Admiralty 
give results at least double or treble the value of four miles in 
twenty-four hours assumed by Ferrel. We must consequently con- 
clude the waters adjacent to the British Isles to be elevated some 
5 to 7 feet above the normal oceanic surface. 
To the north of England the current is compelled to a more 
northerly course. This change in direction, combined with the effect 
from the more rapid shortening of the cosines of these latitudes, seems 
to make necessary on the coast of Norway a still greater rise in 
surface elevation than has already been determined for the coasts of 
England. : 
_ This writer, with data somewhat uncertain both as to direction. and 
velocity, has reached results off the north coast of Norway calling for 
an elevation of over 20 feet in the surface-waters on these shores. 
