114 PHILOSOPHICAL TUANSACTIONS. [aNNO 1750. 



" It was observed, that the waters turned foul the day before an earthquake 

 at Bofogna in Italy : and I was informed, that the water of some wells in Lon- 

 don turned foul at the time of the earthquakes. Which was probably occasioned 

 by the ascent of great plenty of sulphureous vapours through the earth. 



" As to the hollow rumbling noise, which is usually heard in earthquakes, it 

 seems not improbable, that it may be occasioned by the great agitation that the 

 electrical aethereal fluid is put into by so great a shock of a large mass of earth. 

 For, if the like motion of a small revolving glass globe can excite it to the velo- 

 city of lightning, and that with a force sufficient to kill animals, how much 

 greater agitation may it probably be excited to, by the explosive force of an 

 earthquake ! 



" The explosion of a cannon in St. James's Park is observed to electrify the 

 glass of the windows of the treasury. And what makes it still more probable, is 

 the analogy that there is between them in other respects. For, as the electrical 

 flash rushes, with the velocity of lightning, along the most solid bodies, as iron, 

 &c. and as I have seen it run only on the irregular gilding of leather ; so such 

 solid bodies are observed to be the conductors of aereal lightning, which rends 

 oaks in pieces, and has been known to run along and melt an iron bell-wire on 

 two sides of a room, &c. And accordingly it was observed, in the great earth- 

 quake in Jamaica, that the most tremendous roaring was in the rocky moun- 

 tains. And in the late earthquake of March 8 in London, the loudest explo- 

 sions were thought to be heard near such large stone buildings as churches, with 

 lofty steeples and spires. 



" I, who lay in Duke's-Court, near St. Martin's church, and was awake all 

 the time of the earthquake, plainly heard a loud explosion up in the air, like 

 that of a small cannon : which made me conjecture, that the noise was owing 

 to the rushing off, and sudden expansion, of the electrical fluid, at the top of 

 St. Martin's spire ; where all the electrical effluvia, which ascended up along the 

 larger body of the tower, being by attraction strongly condensed, and accele- 

 rated at the point of the weathercock, as they rushed off, made so much the louder 

 expansive explosion. 



"The Rev. John Seddon, says, p. 697, as soon as I felt the shock, I was 

 immediately apprehensive what it was, and went out to see whether there was any 

 thing remarkable in the atmosphere. I then observed a very uncommon appearance; 

 viz. an infinite number of rays, proceeding from all parts of the heavens, con- 

 verged to one point; no luminous body appeared at all. The rays were at first of 

 a bright yellow ; afterwards they became blood-red. This phenomenon was not 

 far from our zenith. It continued about 20 minutes, and then disappeared. 



Dr. Dodridge, p. 718, says, the morning on which the phenomenon hap- 

 pened, was remarkably calm ; but quickly after the shock, the wind rose ; and 



