110 MR. VVILSONF O?^ ELEClfRICITV. 



XIII. 



E.tperimcnts on the Elctlricity of Metallic Filings Jifted through 

 Mcial ; luith Reninrks in anjloer to a Letter of Mr. CiUhberi^ 

 foil. Bj/ Mr. Wm. Wilson. (From the Author.) 



To Mr, NICHOLSON. 

 SIR. 



Anerrorpointea -""N the lafl: number of your Philofophical Journal, I find a 

 oai by Ml. letter from Mr. Cuthbertfon, containing fome remarks ofi my 



CuthbertCon ad- ,, r^ ••....,.. , • 



flitted. letter on the electricity ot metals, in which he notices an error 



ii) jJijc table of refults of experiments, that had efcaped my 

 notice till I read his letter. In that table I have by miftake 

 put P agair.fi copper filinor^fifted through zinc inftead of N. 



Copper filings when fifted through zinc . are .elediificii 

 flrongly with negative eledricity. 



Mr. C.'s objec- Mr. C. in his other remarks does not feem to admit that the 



tion to the pro f^^pa^ating the metals from contad is the caufe of the elearical 



duction or eu'C- to 



trlcity by mere fluid being excited and not touching, becaufe both touching 



reparation of ^j^^j feparating are employed. In the way the experiment8 



metais, confi- , . , , . *, /-i- ■ 



dered. were made touching takes place two wa:ys, viz. the 'ttlings 



Tlie metallic ^ come in contact with the metal plate they are fifted into, 'and 

 ITX ITfeplra- ^'^^7 ^re in contad with the fleve before the^' a rd lifted througii 



ted, and touch ji j but I cahuot conccivc how either ot 'thele contains cbuW 



IneraT"'"""^ ^^^^"^ Jie excitation of the eleaHcity in the 'experiments, if 



As ths cl. the eoniafl of the filings with the plate they were fifted into 



varies With the ^^^ the caufe, we (hould have had the fame efFea with (lie 



fieve it does not . r i 



depend on the fame filings, whatever metal the lieve was made or they were 



l&tterconaB, fifted through ; becaufe as they were always fifre'd into the 



fame plate, the fame metal filings always came in conlad witli 



the fame ir.etal plate, and confequently we fliould iiave had 



the fame effe^s in all cafes with the fame filings; whereas out 



—aid in ^he cf the ten forts of filings that were ufed there was only one 



/r7? ««r./? there mg^.,x ^^.^^ produced the fameetfed with the different fieves ; 



is no inlu.ation, v ' « , ,. ■ i i 



and if the cohtad of the filings with the fieve cxcitetl any elec- 

 tric fluid, it would be difllpaled as fall as excited, becaufe 

 --confequently neither the fieve nor the filings were infulatcd ; confequently 

 It depends on it could have no e [fed on the refults of the experiments. — 

 icji/jraun. 'rj^^p^j;,^^ f^^^^^ neither of thefe conlads excited tlie lluid, it 

 iriLill have been excited by the feparalion. 



I think 



