316 EARTHQUAKES. 



there were movements of the soil to be detected every 

 day, and sometimes many times per day, which to ordinary 

 persons were passed by unnoticed. 



Work in Italy. — The most satisfactory observations 

 "which have been made upon microseismic disturbances 

 are those which have been made during the last ten years 

 in Italy. The father of systematical microseismical re- 

 search appears to have been Father Timoteo Bertelli, of 

 Florence. 



In 1870 Father Bertelli suspended a pendulum in 

 a cellar, and observed it with a microscope. As the 

 result of his observations it was announced that he had 

 perceived the earthquakes which shook Romagna, although 

 to the ordinary observer in Florence these shakings had 

 not been perceptible. 



In 1873 Bertelli, by means of microscopes fixed in 

 several azimuths, made 5,500 observations on free pen- 

 dulums. He also made observations on reflections from 

 the surface of mercury.^ 



One result of these observations was to show that 

 microseismic motions increased with a fall of the baro- 

 meter. Similar observations were made at Bologna by 

 M. le Conte Malvasia, and also by M. S. di Rossi, near 

 Rome. On January 14, 15, and February 25 these three 

 observers at their respective stations simultaneously ob- 

 served great disturbances. 



Similar investigations were made at Nice by M. le 

 Baron Prost. 



Although doubt was cast upon Bertelli's observations 

 they appear to have been the origin of a series of micro- 

 seismical observations, a distinguished leader in which is 

 Professor Rossi, who, in 1874, found that large earthquakes 

 were almost always preceded or accompanied with micro- 



* Comjjtes Bendus, 1875, January to June, p. 685. 



