The Wheeling daily intelligencer. [volume] (Wheeling, W. Va.) 1865-1903, 1869-01-26
Frequency of Enrtnqunke s.

There is an impression that the num-
Der of earthquakes occurring during
the last few years has been greater than
usual, but we are by no means certain
that this is fact. Some recent shocks
on this continent, east of the Rocky
Mountains, a shock in san francisco,
and the terrible calamity in South
America have made earthquakes gen
eral topic of conversation. 1t Will he
found, however, that the average an
nual number of shocks for the last fifty
wears has not been exceeded to any
great extent lately.
NJ. Percy, Professor at Dion, in
France, is the best authority on the
subject OF earthquakes. he has col
lected large amount of Information
on this subject. The foreign consuls OF
the French government i'll every part
OF the globe have been instructed to
furnish him with observations and
with the literature OF earthquakes, ana
circulars were sent, through the agents
of geographical societies, to all travel
lers, asking for statistics and infOrma-
ton; and thus, in the course of few
Vears.M. Percy has accumulated vast
amount of material for study and classl-
tication on earthquakes. Observers were
requested to note the day, hour, dura-
ton, direction, force and extent OF the
shocks; to observe the nature and
character of the noises that preceded,
| accOmpaniCd or followed the shocks !;
to describe succinctly the effects upon
| buildings, the earth, the waters, upon
men and animals; 10 Indicate the
centre Of the phenomenon, which some
times changes; and finally, to record
| all the different meteorological pheno''
mena appearing to have any relation 10
the shocks.
In this way NJ. Percy has obtained
the record of more than seven thousand
| hS1l, tn fah LOTT
and upon which he has attempted to
found a theory of their origin; but, as
his theory has been stoutly opposed by
| biologists, we will cOntine ourselves
| to the facts published by him. 1t APP
pears from his observations that these
commissions occur more frequently dur.
| ing the winter half OF the year than
during the summer; that there is a
| preponderance OF shocks at the equ1-
| nOXes and the summer sOlstice. A
| variation in the pressure of the amos
| phere is found 10 have some COnnec-
ton with the phenomenon, AS the earth
quake action is greatest when the baro-
meter indicates that the weight OF the
atmosphere is the least, and the pres
sure variable.
Tho nature of the earthquake shock
is that of waves propelled from CEN
trail point. These waves are as varia-
| BILE as those of the sea. They are some
and at other times several feet high.
Sometimes they cross each other and
produce rotary motion, which is very
destructive. The geological formation
Ofthe region disturbed has much to do
with the velocity of the earthquake, MS
| through certain strata the shock IS pro-
| PEELED faster than in others.
On land the velocity OF the wave Is
found to vary from forty to one hun.
| dreu and forty miles minute. In 1854
wave caused by an earthquake in ia
pan, travelled across the Pacific to the
shores Of California, i'll about twelve
hours, or at the rate of about six hun
! bred miles per hour.
Observations upon tho duration OF
earthquakes are not very trustworthy.
The personal equation of fright comes
i'll to modify the apparent length OF
| time. They rarely cOntinuo more than
n few seconds; but the imagination OF
| the observer nlagnities the time good
many fold.
In some countries earthquakes of
greater or less intensity occur almost
daily. AT Lima, in Peru, an average
| of forty five shocks may be expected
yearly; and in Chile, sixty-one has
been noted in single year. We are
not aware of the existence Of separate
tables for the United States, but they
could be compiled from material in the
| possession of Nj. Percy. The Bulletin
OF the Royal Academy of Belgium and
| the Memoirs of the Academy OF Dion,
contain annual reports since the year
1913, from which any one interested i'll
the subject could obtain much infor-
nation. Mr.. Mallef, of England, has
also made the study of earthquakes a
speciality, and his publications may be
consulted in the transactions of the
Royal Geographical Society, and the
Royal Society. iStttinlnm'S American
journal Of Science also contains much
Information on this subject.
| 1t may he we'll for a committee in San
| Francisco to examine into the strength
of public buildings, but upon this side
| of the continent there would appear to
be no cause for anxiety, and We imag-
inc our builders will not be prompted
to secure their houses by amy tirmer
foundations or more solid wHlls.-N,
| y. Post.