278 Mr D. Milne on Earthquake-Shocks in Great Britatny 



In Shropshire, it will be seen, under date 27th May 1773, 

 that several very long and deep chasms were formed, from 

 fourteen to thirty yards wide, as also cracks and rents from 

 four inches to six yards wide. At Ripon (Yorkshire) there 

 was, in 1827, a fissure nearly twenty yards wide. In January 

 1838, a rent at Tynehead was formed nearly half a mile long. 

 Under dates, 29th December 1737, 29th December 1769, 31st 

 .January 1773, and January 1787, will be found farther indica- 

 tions of similar effects. 



A curious notice under date 15th July 1757, may here be 

 referred to. It is stated, that '' several small risings as big as 

 molehills, were observed in the morning before the shocks 

 happened, on the sands of the beach, having a black speck 

 in the middle of the top, as if something had issued from it. 

 From one of the hollows between those risings, there issued a 

 strong gush of water, about as thick as a man's wrist." Similar 

 appearances were observed in Chili and Calabria, during the 

 great earthquakes there. They have been generally supposed 

 to be produced by water squirting up ; but this explanation 

 seems by no means satisfactory. 



From the account given of the rent, or " cleft'' as it is 

 termed, produced at the Derbyshire mines, it appears that its 

 direction was due east and west.* This is just the direction 

 which was to have been expected, from an undulation advan- 

 cing in a north direction. It is probable that the vessels in 

 Portsmouth docks, which are said to have rolled on the arrival 

 of the shock there, must have been lying in an east and west 

 direction ; — unfortunately the report given in the Philosophi- 

 cal Transactions, omits this circumstance. t 



4. That most of the Shocks recorded in the Kegister origi- 

 nated i7i, or emanated from, poitits immediately beneath Great 

 Britain^ and were not transmitted from distant regions, must 

 be evident, when the following considerations are attended to : 

 It will be seen, on examining the accounts given of the 

 shocks, (1.), that, with few exceptions, they affected only cer- 

 tain portions of the island ; (2.) that there was, in all the dis- 

 tricts affected, some spot where the concussion and attendant 



♦Philosophical Transactions for 1755, p. 400. t Ibid. p. 351. 



