44 ExptrimenU and Ohfervatkns on the Galvanic Fonver, 



in one hand, and the other wire held by the other, the fenfation of this dry fliock brings a 

 complete recolle£lion of what is commonly called the fleeping of a limb, viz. that prickling 

 that is felt after the limb has been long in a conftrained pofition, and when, I believe, 

 medical people fuppofe there has been a preflure on a nerve. 



I am almoft inclined to believe, that the natural fenfation proceeds from the Galvanic 

 fluid in the human fyftem attempting to reftore its equilibrium by repeated fhocks. A pile 

 in this very flrong ftate gives no figns of eleftricity by a very delicate eleftrometer (which 

 I ufed to the exclufion of the modes of accumulating ele£lricity, on which I think little de- 

 pendence can be placed), and no eifeft could be excited, even though the pile was infulated, 

 and the fliock taken through the metallic arm that fupported the electrometer, by a perfon 

 on an infulating ftool. 



I alfo attempted to charge a Leyden vial in the way * mentioned by you, as ufed fuc- 

 cefsfuUy by Mr. Cruickfhanks, viz. conneding one end of the pile with the outfide, and 

 the other with the infide of the jar. It ftrikes me that it is impoflible a jar would be 

 charged in that manner, as the two fides, in that cafe, are connected by conducing fub- 

 ftanccs, the very mode ufed for difcharging a jar ; if I have miftaken your meaning, or that 

 of Mr. Cruickfhanks, I beg you will correft me. I alfo connefted both wires with the 

 GUtfide, and both with the infide, and even the filver wire of one pile, and the zinc 

 wire of another, alternately with the internal and external fides, without producing any 

 eiFedt. 



I then attempted to charge the vial through the infulated pile, connedling the wires by 

 turns with the condu£l:or of an eledtrical machine and the infide of the jar. By com- 

 paring the change produced by a definite number of the revolutions of the machine, when 

 attached and unattached to the pile, and when the filver and zinc wire were alternated, in the 

 manner above defcribed, no difference could be perceived either in the (hock or fizc 

 and length of the fpark : alfo when the jar was placed between the conduftor, and the in- 

 fulated pile, no difference could be perceived by taking the fhock or the fpark through 

 the pile. 



Thefe experiments were often repeated with the fame rcfults ; and I think they (how 

 clearly that the charge is neither accelerated nor retarded by the pretended plus and minus 

 of the pile. 



I have feveral times obferved,. and wifli it may be attended to by others, that when 

 women and men form a part of the Galvanic circuit, that the women feel almoft the whole 



• Your words are—-" That Mr.- Cruickfhanks, of Woolwich, has charged a large jar fo as to give a 

 " fliock merely by placing the pile between its coatings." This I fuppofe was a private communication, 

 as 1 have in vain looked over Mr. C.'s own papers for the fa£l.---C. 



The communitation was made in converfation. I think the arguments and induftions at p. 243— 245 

 of our IVth volume remove many of the difficulties of theory, arifrag from the low intenfity of the power ; 

 but not this of the aftual fliock. I have charged talc as well as thin filk unequivocally ; but expeft foon to 

 repeat the experiments with a higher pow«r."-N. 



4 fliQck, 



