1 72 On the Effects produced by 



and in some places became thick and turbid. Lake Ontario 

 also felt its effects, and the sea round the Eastern Antilles, 

 Antigua, and its neighbouring islands ; and, although the tide 

 is not known to rise more than 18 inches, it suddenly rose 

 20 feet. 



The atmospheric and other phenomena which usually 

 accompany earthquake, and consequently precede eruption, 

 are, an unnatural calmness of the air, a violent and remark- 

 able agitation of the sea, the sudden bursting forth of sulphu- 

 reous springs, deep rumbling sounds, and violent explosions, 

 resembling the discharge of artillery. The phenomena which 

 precede subaqueous activity are precisely similar to these, 

 except as they may be affected by the mass of water which 

 covers the vent. 



(Tb be continued.) 



Art. XII. On the Effects produced hy the 'Precession of the Equi- 

 noxes» By Sir John Byerley, F.R.S.L. 



{Continued fromYo\.lV.^.'6\Q.) ' 



Sir, 



In advancing a new theory, I had not the ridiculous pre- 

 tensions of imagining that it would at once attain universal, 

 or even general, assent. The astronomical system of Pto- 

 lemy and the vortices of Descartes have still their partisans, 

 who look down with pity on Copernicus and Newton. Even 

 whole scientific academies have adopted errors which a 

 schoolboy of the present day would blush for. To cite only 

 two relative to my subject: — In 1693, the French Academy 

 of Sciences decided that it was preposterous to suppose that 

 the sea and land on the globe did not present an equal extent 

 of surface. Sir Isaac Newton had determined, by theory, 

 the earth to be an oblate spheroid ; but, strange to say, the 

 measurement of a degree of the meridian, by the French 

 mathematicians, which ought to have confirmed Sir Isaac's 

 theory, led the French Academy of Sciences to an opposite 

 conclusion ; and for forty years they taught the world to 

 believe the earth to be a prolate spheroid; or sharpened, 

 instead of flattened, at the poles. 



As to theories of the earth, they are innumerable; all 

 beautiful, all poetical; from Burnet and Whiston down to 

 Buffon and Delisle de Sales ; the latter of whom supposes 

 the solar system to consist of about 1 7,000,000 of planets 

 and comets. 



