like that of a musical string: or what we put a drinking glass into, by rubbing one's finger over the edge; which yet brought to a certain pitch, breaks the glass; undoubtedly an electric repulsion of parts. And from this remarkable similarity in the appearance of earthquakes we gather an invincible argument against the old opinion of their cause; for the tumult of subterraneous eruptions can have no possible place herein. 7ly, We find from all accounts, ancient and modern, that the weather preceding these shocks, was mild, warm, dry, serene, clear, frosty: what notoriously favours all our electrical experiments. This is particularly observ'd by Mr. _Johnson_ and Mr. _Smith_, and other accounts. In the extensive shock of _sunday march_ 18, along the _Sussex_ coast, they take notice from _Portsmouth_, that the day was serene, warm, and dry, and that a shower of rain fell immediately before the shock. Mr. _Bowman_ of _Moulsey_ observ'd a shock there on _may_ 24 last, and says, the air was perfectly serene, and clear. We very well know, that generally, all last winter spring, summer, and autumn, have been most remarkably of this kind of weather; more so, than has been observ'd in our memory; and have had all those requisites, appearances, and preparations, that notoriously cause electricity, that promote it, or that are the effects of it. 8ly, We find the blood-red _australis aurora_ preceding at _Spalding_, as with us at _London_. At the time of the earthquake at _Manchester_ this year, it accompanied it. And this year has been more remarkable than any for fire-balls, storms, wind, thunder, lightnings, and coruscations, almost throughout all _England_. A large ball of fire, with a long fiery tail on _july_ 22, that passed over great part of _England_ northward. Another seen over _London_, passing from west to east, in _october_. Coruscations were seen just before that extensive shock of 70 miles long felt from _Lancaster_ to _Wrexham_, on _april_ 2, last. Fire-balls more than one were seen in _Rutland_, and _Lincolnshire_: and particularly observ'd. And Mr. _Smith_ from _Peterborough_ writes, that a fire-ball was seen the morning of the earthquake, in the upper part of _Northamptonshire_. All these kind of meteors are rightly judg'd to proceed from a state of electricity in the earth and atmosphere: and how far they are actually concerned in causing earthquakes, time, and accurate observation must inform us. 9ly, Mr. _Johnson_ in both his letters to me, on the first and second earthquakes, at _Spalding_, remarks particularly, of their effects being mostly spread to the north and south, and especially felt on the sea coast. We may observe, that such is the direction of _Spalding_ river, which both conducts, and strengthens the electric vibration: conveying it along the sea-shore thence, up to _Boston_ channel; and so up _Boston_ river to _Lincoln_, as we discern, by casting our eye on a map.