476 A YEAR OF COSTA RICAN NATURAL HISTORY 



while five hundred houses were so badly injured that they 

 required removal later. 



From 1 85 1 to 1887, there is a series of records of the num- 

 ber of earthquakes during each year, made by personal ob- 

 servation only and without instruments. Most of these 

 were noted in San Jose and in one year (1876) twenty-four 

 were so recorded, but there is no mention of any particularly 

 strong shocks in Cartago, although doubtless some shocks 

 were felt there. 



When the Observatorio Meteorologico Nacional, later the 

 Instituto Fisico-Geografico, was founded in San Jose in 1888, 

 two seismographs were installed in the Institute, so that 

 from that year there are records both of strong shocks and 

 weak tremblings of the earth. The number so recorded by 

 the instruments in San Jose varies from thirty-seven in 1888 

 (including one disastrous shock in Alajuela and San Jose) 

 to one hundred and eighty-two in 1906, but Cartago was 

 freer from earthquakes than usual during all this period, and 

 it appeared as if the region were becoming more stable. In 

 1909 the seismographs in San Jose recorded only four shocks. 



We settled in Cartago on May 7, 1909, and experienced 

 the first earthquake there on June 23 about 4 A. M. It 

 was strong enough to waken us by the jerky motion it im- 

 parted to the beds but not to cause any particular alarm 

 even among the Costa Ricans. On the fourth of November 

 we felt one slight shock and on the twenty-fifth of the same 

 month there were two. The next occurred on March i, 

 1910, and this last, although we did not consider it alarming 

 and remained at work in our room, caused the Costa Ricans 

 to rush out into the street at the very first instant the tremor 

 was felt. 



On the thirteenth of April, 1910, while P. was away at 

 Atenas, everyone in Cartago was aroused at 12.36 A. M. by 

 a rather violent earthquake that shook us in our beds and 



