—_ 
Sr 
1 SRR T INNS See 
Report on A. Perrey’s Researches relative to Earthquakes. 55 
to deduce the mean greatest and mean least pressure, and the cor- 
responding mean levels, a different result will be obtained. From 
these observations however he considers that he has been enabled 
to deduce results which plainly point to the law which governs 
the effect of the pressure of the atmosphere on the mean level of 
the sea, and may be encouraged to pursue the investigation | 
through a more extended series of observations. in order to arrive 
at the most accurate conclusion that the observed facts may 
justify. 
In conclusion a formula is given for determining the correct 
height of the tide, or of the mean level of the sea:— 
Let L denote the correct height of the tide, or of the mean 
level of the sea; 
B the mean pressure of the atmosphere ; 
4 the observed height of the tide, or of the mean level of 
the sea ; 
8 the corresponding height of the barometer ; 
D the ratio of the specific gravity of mercury to that of 
sea-water : 
then L—=i+(@—B)D. 
Examples are given of the application of this formula. 
Art. X.—Report to the Academy of Sciences, Paris, on the Re- 
searches relative to Earthquakes of M. Alexis Perrey; by the 
Commission, MM. Lrovvitie, Lamé, and Exie pe Beaumont 
reporter.* 7 
Te Academy has charged us, MM. Liouville, Lamé and my- 
self, with reporting on a memoir presented March 21, 1853, by 
M. Alexis Perrey, Professor in the Faculty of Sciences of Dijon, 
On the relations which may evist between the frequency of Earth- 
quakes and the age of the moon, and on a Note presented the 
of January, On the Jrequency of Earthquakes relatively to the 
times of the moon’s passing the meridian. 
When the memoir of M. Perrey was presented on the 21st of 
March, M. Arago was appointed on this commission. The death 
of our illustrious confrere, which happened soon after, left a va- 
cancy in the Commission; and subsequently to the reading of 
the Note on the 2d of January, one of our number, M. Lamé, 
was named for the place. : 
Arago, whom nothing escaped which bore on the physics of 
the globe, followed with continued interest the researches of M. 
Alexis Perrey. The Academy has not forgotten the care with 
* From the Comptes Rendus, xxxviii, June 2, 1854. 
