2C0 
THE GEOLOGIST. 
It was learnt shortly afterwards that a most violent earthquake had 
ravaged, on the night which separated the 16th and 17th of December, 
the greater portion of the two Sicilies, especially the tovra of Salerno, 
Potenza, and Pola. Many thousands of the population perished in the 
Basilicata and neighbouring provinces, where the phenomena appear to 
have been concentrated. Naples itself experienced three violent shocks, 
which, however, were fortunately unattended by loss of life. Other 
convulsive movements of the earth were felt in Naples on the 1 9 th, 
20th, and 23rd of the same month. The inhabitants, much terrified, 
hoped and prayed for an eruption of Vesuvius. The earthquake of the 
1 7th December produced a certain effect on the south parts of Germany. 
Bavaria and Wurtemburg likewise experienced its influence; and on the 
20th December, at half-past five o'clock in the morning, violent shocks 
were felt at Agram, in Crotia. The undulations of the ground took a 
direction from the south-east to the north-west, and the shaking of the 
earth lasted about three hours and a half. 
During the early days of last January, the amplitude of oscillation in 
the magnetic needle of the Brussels Observatory evinced considerable 
irregularity, especially on the 5th, 6th, and 7th of that month. But on 
the 9th the needle was, moreover, suddenly displaced at each oscillation. 
The papers made known shortly afterwards that an earthquake had 
taken place on the 8 th and 9 th of January, at Varna. 
These data evidently tend to prove that a certain relation exists 
between the phenomenon of earthquakes and terrestrial magnetism.* 
But this relation of which we speak, to what extent is it established ^ 
Can we admit, with Mr. Evan Hopkins, that terrestrial magnetism is the 
great and sole agent of nature by which all geological changes have 
been, or are, accomplished ? Certainly not. This author's hypothesis 
is, however, extremely curious. We are indebted for an abstract of it 
to an accomplished geologist. Miss Catherine J. B. Taylor, and we are 
thus enabled to let our readers judge for themselves. Mr. E. Hopkins 
endeavours to demonstrate that " the slow operation of that power which 
we call terrestrial magnetism accounts for all the changes observed on 
the surface of the earth, in the structure, combinations, and relations of 
* Whilst writing the above, the following passage of Humbolt'.s is irresistibly 
called to mind : — " VVheu the needle, by a sudden disturbance in its horary course, 
indicates the presence of a magnetic storm, we are still unfortunately ignorant 
wliether the scut of the disturbing cause is to be sought in the earth itself or in 
the upper regions of the atmosphere." (Cosmos, vol. I.) — T.L.P. 
