TIME OF EARTHQUAKE, RATE OF rROPAGATION. 
41 
Rome. 
The followino; information has boon sent to me by the Director 
of the " R. TJfficio Contrale di Meteorologia e Geodinamica," Rome. 
Rocca di Papa. 
Main Earthquake. 
\. " I\rirrosi?inomctroui'afo Agamennone " with 2 components : — 
N — S. Arrival of preliminary vibrations, 10 hours 32 minutes 47 
seconds i3 seconds. 
Second preliminary phase, 10 hours 41 minutes 58 seconds. 
Long waves, 10 hours 56 minutes 28 seconds. 
End, 11 liours 16 minutes 6 seconds. 
E — W. Preliminary tremors, 10 hours 32 minutes 48 seconds. 
Second preliminary phase, 10 hours 41 minutes 58 seconds. 
Long waves commence vaguely about 10 hours 57 minutes 6 seconds. 
End about 12 hours 0 minutes 6 seconds. 
2 ■' Pendolo Orizontale " : — 
Arrival of preliminary vibrations, vague ; about 10 hours 32 minutes 59 
seconds. 
Second preliminary phase, 10 hours 41 minutes 37 seconds. 
Long waves, 10 hours 55 minutes 36 seconds. 
3. " Microsismometrografo Universale Agamennone " with 3 components : — 
Light registration on all three components. 
Second Earthqnake. 
During the phase with slow waves of the above earthquake, a second and 
distinct group of light instrumental waves were superposed on both the 
records registered by instrument No. 1, at exactly 11 hours 1 minute 38 
seconds, indicating a second earthquake shock. These grow to a maximum 
of 0*2 ram. on the X — S component, and 0*6 mm. on the E — W at about 
11 hours 2 minutes 12 seconds and then decrease and fininsh about 11 hours 
7 minutes .54 seconds. 
On instrument No. 2 these superposed vibrations are not identifiable 
because of the remarkable oscillation which still persisted from the regis- 
tration of the big earthquake shock. 
On instrument No. 3 however, the lightest waves the instrument can record 
are found again corresponding to those registered on instrument No. 1 but 
only on the horizontal component. 
