314 EARTHQUAKES. 



house so that it fell near to the microphone pit caused 

 a sharp creak in the telephone and a movement in the 

 needle. 



The nature of the records I received from this con- 

 trivance may be judged of from the following extract from 

 my papers. 



d telephone creaks 





h. 



m. 







1879. 



Nov. 12th 7 







P.M 



contact of needle 





7 



2 



» 



difficult to set th 





7 



.3 



» 



needle swings an 





7 



4 



„ 



>> 





7 



6 



» 



„ 





7 



6 



» 



» 





7 



10 



»» 



3 more swings 





7 



11 



>» 



again „ 



Here I went out, took away the covering, and examined 

 the microphone. Toothing wrong was to be observed. 

 All that I saw was one small ant. I do not think that 

 this could have caused the disturbance, because it could 

 not get near the instrument. 



On the succeeding nights I experienced similar disturb- 

 ances, and it seemed as if they might possibly have been 

 the prelude to several small shocks which occurred about 

 this time (November 15, 16, and 17). On November 17, 

 at 8 A.M., the needle was found in contact, and again at 

 5 P.M., and at 6 p.m. the shock of a small earthquake was 

 felt which caused a rattling sound in the telephone 

 for about one minute after the motion had appeared 

 to cease. The needle swung considerably, but did not 

 come in contact. 



The great objection to these observations is that it is 

 possible that the movements and sounds which I have 

 recorded might, with the exception of one case w^hen the 

 shaking was actually felt, possibly have been produced by 

 causes other than that of the movement of the ground. 

 To determine this I subsequently put up tw^o distinct sets 



