Pertabk ElsBr'uat Machine. 509 



cppofite end? upon the wires -jf the c!ire<5\ors, whereby a fliock may be font through any 

 particular part of the body, as wcU as if the medical jar were ufed with Lane's eleftrome- 

 ter. It is immaterial whether the machine, in this operation, be held on a table or (land, 

 the operator's knee when fitting, "the bed of a patient, or even the ground by the fide of a 

 river in cafe of neceffity where the patient is apparently drowned : nay, it may be held, by 

 a perfou Handing, in one arm, whilft the other hand turns the winch. 



When the fpark only is required, the fmall chain is removed from the colleilor, and alfo- 

 the long chain, conneded with the hook at H, is taken away ; the inner ball is then fixed fo 

 as to touch the coUeclor, by means of the adjufting nuts ; in which cafe the colle£lor, the 

 ■wire in the tube, Ihd the fccond long" chain connefled therewith, form together one con- 

 duftor. After the exterior end of this chain is attached to the wire of one of the direflors, 

 the fpark fnay be dire£ted into any particular part of the body; when the eye is the part: 

 affeaed, a pointed wire mufl; be ufed inftead of the wire carrying the ball, which mull be 

 made to fcrew into the focket of the dire£lor. 



When a fpark is taken out o^the body, the patient mud ftand on the ftool, and hold the 

 chain, connefted as before, in his hand ; and then the operator, or affiftant, may take fparks 

 from him, as in other machines. 



If the patient be nervous, or afraid of the fpark, it would be fafer to hook the chain to 

 the coUedlor for fear of breaking the tube, and hold it at a diftance from the eSge of the 

 box in a perpendicular direQion. The fparks taken from an Lnfulated body are flronger 

 than thofe fent into any perfon by reafon of the fmallnefs of the conductor, which is per. 

 haps the greateft. defecl of the machine : this defeat; may, however, be remedied by placing 

 any rounded metallic fubftance, fuch as a large candleftick, upon the ftool near the ma- 

 chine, and conneifling the chain with it, fo as to make it a part of the conductor, and then 

 the fparks will become more denfe. 



There is yet another way of adminiflering the ele£lric fluid, which cannot properly be 

 called adminiflering either the fpark or the fliock; in which cafe the fenfation is not fo 

 momentary as is that caufed by the fhock, but more pungent than that of the fimple fpark ; 

 it may be called the interrupted fliock, and is thus eiletlcd : Let the fhort chain fall from tlie 

 coIle£lor upon the coating of the plate, and conneft one of the long ones with the hook 

 at H or I, and fuffer it to be extended on the table ; then, the inner b.ili toucliing the coi- 

 fc<!^or, turn half a dozen rotations before the finger be prcfented to the outer ball • and 

 becaufe the circle is not completed between the two coated furfaces of the plate by p^rual 

 condudlors, a continuous flrcam of denfe fparks will ifTue into the finger, caufing a more 

 pungent fenfation than would be felt from a fimple fpark of a much more powerful ma- 

 chine. I (hould fuppofe the fliniulant power of tliis mode of eledlrifyijig any particular 

 limb to be very great, and I underfland it has been pratlifed by fome elcclrieiar;s, by meaijs 

 of a charged jar where the circle is not completed by perfect condu£tors. 



If a fmall pocket-jar, in a cafe, be added to this machine, it v\ill be capable of producing 

 either a negative or pofitive charge in it; for if tlie jar held by the b.all connecflcd with its 

 inner coating be prcfented fo as to receive a pofiiivc charge on its outer coating from the 

 outer ball of the macliine, the inner coating will of courfe be negatively charged ; and if 

 it be placed upon the ftool, or inverted goblet, till tlic hand has taken lioid of the outfide,, 

 the negative cliarge will be retained, 



Thuo 



