5900 Reviews—Earthquake Predictions. 
a series of conditions similar to the conditions of linear, and semi- 
circular reefs and Atolls of more recent times, and have reason to 
believe that the Atoll at Arbigland is unique. A more fully detailed 
description, with a list of both genera and species, will at no distant 
date be published. 
RAVE ws. 
EHarRTHQUAKE-PREDICTIONS. 
(1) M. J. Delauney. Nouveau principe de Météorologie fourni par 
Vexamen des tremblements de terre. Comptes Rendus (Nov. 
17, 1879), vol. Ixxxix. pp. 844-5. 
(2) M. J. Pelauney. Note relative aux indications formulées par 
lui, il y a quelques années, sur les époques probables des 
grands tremblements de terre. Comptes Rendus (Sept. 10, 
1883), vol. xevii. p. 609. 
(3) M. Faye. Sur certaines prédictions relatives aux tremblements 
de terre. Comptes Rendus (Sept. 17, 1885), vol. xevii. pp. 
620-3. 
(4) M. J. Delauney. Note sur les époques probables des tremble- 
ments de terre. Comptes Rendus (Sept. 24, 1883), vol. xevii. 
pp- 699-700. 
(5) M. Daubrée. Sur linsuffisance des relevés statistiques des 
tremblements de terre pour en tirer des prédictions. Comptes 
Rendus (Oct. 1, 1883), vol. xevil. pp. 728-9. 
HE power of prediction,” says Prof. Judd, “is alike the crucial 
test and the crowning triumph of a scientific theory.” It may 
even, as in the case of eclipses, precede the accurate knowledge of 
the theory. M. Delauney has recently attempted another example 
of this curious inversion in his endeavour to point out certain years 
as more especially liable to seismic disturbances. 
Towards the close of 1879, he presented a memoir to the French 
Academy, published in abstract as the first of the above-mentioned 
papers. His calculations were founded on the tables of earthquakes 
between 1750 and 1842, compiled by M. Alexis Perrey, and he 
points out that there are certain groups of years recurring at regular 
periods which are more than usually fruitful in earthquakes. Two 
of these groups have a period of 12 years each, one commencing in 
1759, and the other in 1756. ‘Two other groups have a period of 
28 years each, the first commencing in 1756, the second in 1778. 
M. Delauney notices the approximate equality of these two periods 
with those of Jupiter and Saturn, which are about 11-9 and 29-5 
years respectively, and remarks that the epochs of the maxima of 
the first two groups coincide with those when the planet Jupiter 
attains the mean longitudes of 265° and of 135°, whilst the epochs 
of the last two groups coincide with those when the planet Saturn 
attains the same mean longitudes. He concludes that ‘“ earthquakes 
appear to pass through a maximum when Jupiter and Saturn are 
found in the neighbourhoods of the mean longitudes of 260° and 
