-Astrenomy. 163 
obtained from a study of Perrey’s tables of earthquakes from 1750 
to 1842. He finds two groups of Maxima, commencing in 1759 
and 1756 oh ec each with a period of about twelve y years ; 
and two other groups, commencing in 1756 and 1773 respectively, 
with a hod of about twenty-eight years. He remarks that 
those of the first two groups coincide with the times when Jupiter 
reaches the mean longitude of 265° and 135°; while those of the 
last two coincide with the times when Saturn reaches the same 
longitudes ; whence he infers that terrestrial earthquakes have a 
maximum when these planets are in the mean longitudes men- 
tioned. Delauney attributes the increased number of earthquakes 
in winter which Perrey has found to reach a maximum in Novem- 
pit 
and Saturn to be due to their passing through meteor streams 
situated in mean longitudes 135° and 265°. As a consequence of 
this he ventures to predict an oe number of sat ert or a in 
the years 1886, 1891, 1898, 1900, . ee, 
The Problem of the Se epiie —The tides in this narrow 
strait between Eubcea and the mainland of Greece, have from 
Classic times been a scientific puzzle, for which a solution has 
the Aigean Sea, which would be wap at the syzygies. The 
gs This formula, ta in which 7=length and A= 
depth of the lake), when ioannd to the channel of Talauda, whose 
length is 115 kilometers and maximum depth 200 fathoms, gives 
for the time of vibration 122, 100, and 86 minutes, nines as 
the mean depth is taken at 100, 150 or 200 fathoms. These 
results agree well with the observation of eleven to fourt n tides 
per day, (which would give from 135 to 106 minutes for a — 
yen, and would seem to confirm M. Forel’s idea. . 6. 
American Ephemeris and Nautical Almanae A pes he 
tha 1882, Washington, 1879.—In this volume of the National 
Ephemeris, Professor Newcomb has introduced several important 
changes, which were suggested by him approved by a com- 
Mittee of the National Academy of Science 
