ON THE FACTS AND THEORY OF EARTHQUAKE PHENOMENA. ID 
great, it is very small in proportion to the enormous area embraced—nearly 
ten times that of the basin of the Rhone; and he justly concludes, that, 
were it not for the penury of records in those regions, so much of which 
is semibarbarous or thinly inhabited, the total number in it would be far 
greater than he gives. While the general character of shocks here is not 
that of great intensity, instances are to be found of some, of disastrous power. 
The relative numbers are for 
Winter Solstice «., «. -sseucck ease 2°90 
Spring Equinox ............ vex -O'70 
Summer: Salstipe is ois oa fae ved 1:05 
Automnal Equinox: ......,:..:'6. O91 
and as respects horizontal direction, the results are,— 
ewe ROU te dase cot atesad @artiaiattve Mito 
INBEiis adiSale tic dmciee dete ann ate OOO 
Beh Wee hee: sa als't area ain'e gerd 
ere NaN ee tery) bee ded 0:50 
PRE SASS) Gis aap alae eh 117 
NG. ONE ce as at. ek Be 
ee eee Ue 1-33 
OR ee ee SRR STE 
from which Perrey obtains a mean general horizontal direction of 
W. 2° 39' N. to E. 2° 39’ S. 
This is again very much the line of the Lower Danube itself, which, how- 
ever, over so vast an area, and fed by vast rivers poured into it on the 
northern side between great flanking ranges passing more or less north and 
south, can in reality exercise little or no influence; and too much stress 
must not be laid upon any observation as to line of direction, even when the 
azimuth surface may be reliable. This applies to every earthquake country ; 
uninstructed observers are very liable to mistake the direction of movement, 
by confounding the direct effects of the shock with those due to inertia of 
bodies moved. In the Danube basin, it must at present remain undecided 
whereabouts the centre or centres of disturbance proper to the region are 
to be found. On the north, the Carpathians probably are above the centre 
for those whose horizontal direction is more or less north and south; but 
whether the shocks from east to west, and veering towards the north or 
occasionally to the south, have their origin in the Caucasus, or beneath the 
eastern extremity of the Euxine, or are also in connexion with the great 
seismic energies that so powerfully and frequently display themselves in 
Syria and the south-east, indeed all over Asia Minor, yet requires to be 
investigated. 
- In the region of the Italian Peninsula, Perrey includes the whole of Italy 
and the mass of the Alps, exclusive of Savoy (which is included in the 
basin of the Rhone), with Sicily, Malta, Sardinia, &c., reaching into the 
centre of the Mediterranean Sea; and, on the north, all the localities whose 
watersheds are not into the Rhone, Rhine, or Danube. For the con- 
ventional limits which Perrey has fixed for himself in deciding upon the 
isolation in point of time of each distinct earthquake, often in this region 
continuing for many days with little interruption, the memoir itself must be 
consulted. 
