434 THE MA NIL A OBSER VA TOR Y 



With these micrometers one ten-thousaiidtli of tlie millimeter can be 

 read.* 



Since the 3' ear 18<S8 tlie astronomical section lias had a twofold 

 duty: first, it has ,<fiven ever}' day the exact hour of noon in Manila 

 civil time, an<l, second, it has re<(ulated nearly all the chronometers 

 of steamers and sailing vessels entering Manila Bay. So acceptable 

 has been this work of the observatory tiiat more than a hundred 

 chronometers liave been brouglit in each year since January 1, 1894. 

 The astronomical department has also constantl\' informed the pub- 

 lic of Manila of all phenomena worthy of notice, such as solar and 

 lunar eclipses visible in the localit}', the ap[)earance of comets, 

 transits of Mercurv, and meteoric showers. The building and entire 

 equipment were provided at the exclusive expense of the Jesuit 

 fathers. The astronomical department was to have l^een officially 

 recognized by the S])anish government for the financial year 1898, 

 but unfortunately war em})arrassed all the scientific ])rojects so much 

 cherished by the fathers of the observatory. 



The study of earthquakes and seismic ])henomena dates almost 

 from the beginning of the observatory, when the first instruments 

 used for this study were pendulums of verv simi)le c^nistruction, for 

 tracing the horizontal and vertical movements of the ground. Other 

 instruments were afterward acquired for direct observation and for 

 recording pur|)oses. Soon after the great earthquake of 1880, wi)ich 

 nearly laid the city of Manila in ruins, the Rev. Father Faura, 

 director of the observatory, ]>ul)lished a verv interesting work about 

 the earthquakes. Hourly microscopic observations were commenced 

 in January of 1881, and in 1887 the Monthly Review began to be illus- 

 trated with the records of earthquakes that occur so frequentlv in 

 some part or other of the archipelago. The seismic instruments now 

 actually employed are all firmly fixed to the base of a massive pier 

 that runs through the right tower of the main building. 



A fair idea of these instruments may l^e had in the work Ln Seis- 

 mologia en Filipinns (pages 4-16). This publication of the observa- 

 tory is a very important one, and contains a detailed catalogue of the 

 long series of earthquakes that have been felt in the Philii)pines from 

 1599 to 1890, with the dates of their occurrence and a statement of 

 their severity. Father Joseph Coronas has recently published an ac- 



* See the pamphlet : Uer Photo clironograph in seiner Anwendung zu Polhohenbestiminnn- 

 gen, Von Dr Otto Knopf in .Jena (Sonderabdruck aii." der Zeitsfhrift f'tir InstniiM'-ntiMi-lcnride 

 18'j4, Heft:'.), (Vei-lag von .Julius .Springer in Berlin). 



