CIRCULAE REIATIYE 



TO 



EARTHQUAKES. 



The Smithsonian Institution is desirous of collecting in- 

 formation in reference to all phenomena having a bearing on 

 the physical geography of this continent ; and, in behalf of the 

 Board of Regents, it is respectfully requested that you will 

 furnish us with any information which you may possess, or be 

 able to obtain, in regard to the earthquake which lately occurred 

 in your neighborhood. 



It will be interesting to determine the geographical limits of 

 the disturbance, and to ascertain whether it was confined to any 

 particular geological formation. If the direction of the shock 

 was observed at a few places, the centre of commotion could be 

 determined; and if the time were accurately known at different 

 points, the velocity of the earth-wave could be calculated. 

 Hence, an answer is requested to the following questions, viz : — 



1. Was the agitation felt by yourself, or by any other person 

 in your vicinity? 



2. What was the approximate time of the occurrence ? 



3. What was the number, and duration, of the shocks ? 



4. What was the direction of the motion ? 



5. What was the character of the disturbance ? was it verti- 

 cal, horizontal, or oblique ? was it an actual oscillation ? an 

 upheaval and depression, or a mere tremor ? 



6. Was there any noise heard? and if so, what was its cha- 

 racter ? 



Y. Was the place of observation on soft ground, or on a hard 

 foundation near the underlaying rocks of the district ? 



(46) 



