136 PHILOSOPHICAL TRANSACTIONS. [aNNO 1764. 



honest and ingenious mason, who has contracted to repair the damage done by 

 the lightning, to not less than 25 tons. An amazing quantity ! 



The abovementioned Mr. Stanes was employed a few years since, in the re- 

 pair of the steeple of St. Mary le Bow in Cheapside, which was injured by a 

 very rare and uncommon accident. At its erection, the builders had employed, 

 near the top of the spire, for additional security, several iron cramps ; the ends 

 of which, by being exposed to the weather, became rusty, swelled, and so 

 much enlarged, as to raise the stones above them, and to deflect the top of the 

 spire 6 inches from the perpendicular. Danger being apprehended from this 

 situation, the spire was taken down several feet of its length, and properly 

 repaired. This ought to be a caution to succeeding builders, that if, in edifices 

 of this kind, they find it ex[jedient to eniploy cramps, they should be either of 

 copper, which is not liable to swell by moisture ; or, if iron be used, so much 

 space should be left in the under bed of the stones, which immediately cover 

 the cramps, that they may have room to extend themselves without danger to 

 the building. This remark, though not immediately relating to our present 

 purpose, will not, I hope, be thought impertinent in this place. 



But to return : this thunder-storm had been preceded by several very warm 

 days. The nights had scarcely furnished any dew : the air was quite dry, and in 

 a state perfectly unfit to part with its highly-accumulated electricity without vio- 

 lent efforts. This great dryness made the stones of St. Bride's steeple, and all 

 other buildings under the like circumstances, far less fit than if they had been 

 in a moist state, to conduct the lightning, and prevent the mischief. For 

 though this thunder-storm ended in a heavy shower of rain, none except a verj' 

 few large drops fell till after the church was struck ; and I have no doubt, but 

 that the succeeding rain prevented many accidents of a similar kind, by 

 bringing down with every drop of it part of the electric matter ; and thereby 

 restoring the equilibrium between the earth and clouds. It is frequently taken 

 notice of in attending to the apparatus for observing the electricity of the clouds, 

 that though the sky is much darkened, and there have been several claps of 

 thunder at no great distance, yet the apparatus will be scarcely affected by it ; 

 but as soon as the rain begins, and falls on so much of the apparatus as is placed 

 in the open air, the bells of the apparatus in the house ring, and the electrical 

 snaps succeed each other in a very extraordinary manner. This demonstrates, 

 that every drop of rain brings down part of the electric matter of a thunder 

 cloud, and dissipates it in the earth and water ; and prevents the mischiefs of its 

 violent and sudden explosion. Hence, when the heavens have a menacing ap- 

 pearance, a shower of rain is much to be wished for. 



From these considerations, I have no doubt, but that the mischief done to 



