Account of a 'Thunder-form in Scotland. 1 4 - 
half diameter*; and alfo by means of another metallic body 
of equal dimenfions with this prime conductor ; then, there 
will be no kind of comparifon between the brength of the 
returning froke obtained out of the bribing dibance of the 
prime condudor, and the brength of the main froke received 
immediately from the prime conductor, the fharpnefs and pun- 
gency of the returning froke being fo much fuperior. The 
returning broke in this cafe is like the fudden difcharge of a 
weakly eledrified Leyden jar , provided that due attention be 
paid to the four rules for obtaining a very brong returning 
broke, as laid down in fedion 307 of my Principles of Elec- 
tricity. 
§ 28. When I performed the experiment of the returning 
broke, by means of a bill bronger eledrical apparatus, the 
commotion -j- felt was iimilar to that of a Leyden jar , bronglv 
eledrified, fuddenly difcharged through my body; fo that, 
having taken the returning broke eight or ten times one 
morning (without having taken the main froke a fingle time 
that day), I felt a conhderable degree of pain acrofs my cheb 
during the whole evening, and a difagreeable fenfation in my 
arms and wribs all the next day. 
I have alfo found, that (by an advantageous difpolition of the 
apparatus) metal J may be melted by means of the eledirical 
returning froke, not only entirely out of the ft r iking diftance 
but even without any communication with the common bock, 
although the conduding body, from which iffued the eledrical 
* See Principles of Ele&ricity, § 593* 594> an< ^ 595* 
•f* See Principles of Ele&ricity, § 304 and §310. 
1 See Principles of Eledricity, from § 603 to § 606, inclufirely. 
Vo l. LXXVII. U 
fluid 
