64 REPORT—1850. 
ficient bases, generally confined to some one district, so that none of their 
conclusions can be received as certain or even very probable yet. 
The three last of these authors come to the conclusion, that in the tropics 
at least, the periods of the equinox are rich in earthquakes. 
‘ Tdeoque post austros noxii precipue terre motus. Noctu Auster, interdiu 
Aquilo vehementior...... .+eeeees-+ Et autumno ac vere terre crebrius 
moventur, sicut fiunt fulmina...........++- .- Item noctu seepius quam 
interdiu ; maxime autem motus existunt matutini vespertinique : sed propinqua 
luce crebri, interdiu autem circa meridiem. Fiunt et Solis Luneque defectu, 
quoniam tempestates tune sopiuntur. Precipue vero cum sequitur imbrem 
zestus, imbresve eestum.”—Plin. Hist. Nat., 1. ii. 49, 84. These, like many 
of the opinions of the ancient learned upon similar questions, are but the ex 
cathedrd repetition of popular and ill-founded notions. 
Perrey’s large catalogue (Mem. Cour. des Scav. Etran. de Belgique, tom. 
xix.) applies to central Europe or to the basins of the Rhine, Rhone, Danube, 
and to France and Belgium, only, and extends from the 9th to the 19th cen- 
turies. 
As we purpose returning to this part of our subject upon an extended base, 
it is scarcely worth while here to extract his tables, merely stating that his 
general result shows a preponderance of earthquakes in the winter, ὃ. e. in the 
months of January, February and March, for the whole, which seems again con- 
firmed by the discussion alone, of the results of the 17th, 18th and 19th centu- 
ries, during which the accounts are more to be relied on than at remoter dates. 
Perrey’s Table, in which he seeks to deduce the resultant direction of 
all shocks in a given region, and the inéensity of the shock, on the assumption 
that this intensity is proportional to the number or reiteration of shocks at a 
given point from one direction, is probably of doubtful value, from the more 
than uncertain hypothesis on which it rests. 
On the Influence of the Season of the Year and Time of Day upon Earth- 
quakes.—Von Hoff remarks, “ As we have already noticed, a dependence of 
the earthquake upon the time of year has occasionally been supposed to have 
been remarked. In the equinoctial regions earthquakes have been thought to 
occur more frequently during the rainy season than at any other time of 
year. Sometimes they have been supposed to be peculiar rather to the pe- 
riod of the equinoxes, sometimes to the winter months; with many other 
similar opinions. Indeed examples are not wanting which appear to favour 
such views; as for instance, the observation, that of all the earthquakes 
which occurred in Sicily from 1792 to 1831 (Hoffman in Poggendorff’s An- 
nalen, b. xxiv. s. 52), double as many took place in March as in any of the 
other months. Still however an almost more profound obscurity hangs over 
the question, whether earthquakes and volcanic eruptions are more peculiar 
to one time of the year or day than to another, than over the consideration 
of the other connections of these phenomena with those of the atmosphere. 
This subject has also been treated of in an elaborate manner in another 
paper on the causes of earthquakes (Mémoire couronnée, Utrecht, 1820-28, 
and enlarged, Leipzig, 1827-28) by Herr Kries, who has brought forward 
instances in no small number, which prove that earthquakes, even of the 
most violent kind, have occurred at every time of day and in every season 
of the year.” 
“1 myself (says Von Hoff) have in another place (Poggendorff’s Annalen, 
b. xxxiv. (110) 8. 99 f.) made the experiment of collecting and arranging 
all the instances of earthquakes which occurred during ten years, in order 
to find whether any one time of the day or year presented a greater 
number of these phenomena than the others. The result of these re- 
