282 TENTH ANNUAL REPORT, ETC. 



A phenomenon of thunder. 



Weld, 3Ie., Jidij 18, 1854. — At sunrise in tlie morning, I heard re- 

 peated peals of heavy thunder while no clouds were visible above the 

 horizon. The thundering continued for several hours. For some 

 time not a single cloud was visible, yet the thunder was very heavy ; 

 occurring at intervals of a few minutes. At last, a few flying cumuli 

 appeared, but none from which thunder could proceed. No thunder- 

 clouds were visible during the day. It could not have been any other 

 sound mistaken for that of thunder ; for the peals were l^rolonged 

 rolls, sometimes nearly one-half a minute in length, having their 

 maxima and gradations like common peals of distant thunder. I could 

 not determine satisfactorily from which direction the sound proceeded. 

 Afterwards, however, I learned that the thunder-storm was to the 

 east of us. At a village eight or ten miles east of us on the morning 

 named above, a thunder-storm was visible low down in the eastern 

 horizon, which darted forth vivid flashes of lightniugj and gave out 

 heavy peals of thunder. 



