734 THE POPULAR SCIENCE MONTHLY. 



allel rows of trees have been inflected, and fields and portions of fields 

 have changed places. Houses have also exchanged situations with 

 each other. 



4. It has been observed that clouds have become fixed or sus- 

 pended over particular spots affected, or about to be affected, by 

 earthquake, as in London, in 1749, in Calabria, in 1783 ; and it is more 

 than probable that the fog that enveloped Euphemia, in Sicily, in 1638, 

 Millitello in 1693, and other places when they were destroyed, arose 

 from the operation of one cause. 



5. Explosions of great violence frequently attend these convulsions, 

 often with disastrous results. When Millitello was destroyed, there 

 was a great explosion heard in the fog that enveloped it ; traces were 

 noticed afterward as of the presence of fire on the rocks in the neigh- 

 borhood, and the vines in the country surrounding it appeared as 

 though they had been seared by fire. A similar explosion was heard 

 in 1783 at Castel Nuovo, in Calabria, when that place was over- 

 whelmed. 



6. A further peculiarity is the exemption of certain spots, although 

 the shocks were felt in all the surrounding neighborhood. Thus, at 

 Manchester, in 1777, St. Paul's Church and the Dissenting Chapel es- 

 caped. Both of these were low buildings without steeples, and the 

 church situated over a common sewer ; but other moi'e lofty buildings, 

 especially those with metal pipes attached, felt the shocks severely. 

 At Blockley the shocks were experienced strongly at the church, but 

 very slightly at the chapel about 300 yards distant, and the latter was 

 constructed without water-pipes. 



7. Earthquakes are very frequently attended by thunder and light- 

 ning. At Munster, in 1612, thunder and lightning were heavy during 

 an earthquake ; and in Sicily, in 1693, it caused very great mischief. 

 Tliis conjunction of lightning with earthquake was noticed by Luke 

 Howard, and constitutes what he designates " spurious earthquake." 

 One of the cases he mentions occured in Radnorshire: "At Knill 

 Court the oscillation of the house was plainly perceptible, and felt by all 

 the family, and that, too, in several apartments, and was accompanied 

 by a peculiar rumbling noise. At Harpton, a severe storm of thunder 

 and lightning was experienced the same night and at the same time." 



8. Peculiar rushing noises have also at times been perceived, as in 

 Staffordshire in 1692, and London in 1749. 



9. These convvilsions are attended by the disturbance of the mag- 

 netic needle, and compasses on board shij) are frequently for a time 

 useless. On the 19th of January, 1845, on the Thames steamer, dur- 

 ing an earthquake in the West Lidies, they revolved on their pivots 

 with great rapidity ; and on the 29th of October, 1867, during a hurri- 

 cane, there were shocks of earthquake at St. Thomas's, and the elec- 

 trical disturbance was so great as temporarily to render the compasses 

 unavailable. 



