9kv8. MeafUre of Ele.Uricity by the Explofun oj JVirc, 



the- fianTr,.cyen- though the charged furface (liould be greatly varied. But it appeared,. tie*' 

 firable to afcertain the proportional quantities of eleclriclty required to explode different 

 lengths of the fame wire. For this purpofe 2,3 iitchcs of wire were exploded by the jar 

 No. I, by five turns of the winch; which was probably too great a quantity, for the ignitioa 

 was very (trong, and deflagrating globules were thrown about. But by a more careful re- 

 petition of the experiment with i\ inchss of wire, the ignition and partial melting of the-, 

 wire were very nearly the fame as in the experiments which had been made on lengths of. 

 five inches. From thefe experiments there fcems reafon to fuppofe that the quantities o€, 

 ■ fjleftricity may be as the lengths of the -wires exploded. 



A battery of fifteen jars,.Gont;uning about 17 fquare feet of coated furface, was tligii- nfed.», 

 to explode five inches- of the wire. Nineteen turns rendered the wire faintly rqd hot; but,, 

 20 turns caufed it to explode in the fame nifiiiner as in the experiments with the jars. 



Half the lengthaf wire, namely at inches^ was in the, next place fubmitted to the ex.^, 

 plofion of the battery. Twelve, turns ignited the w.irj?, and 15 .turns caufed it to explode.i> 

 with fomev»hat more violence than-in.- the^expe,rimeiits with the jars,. 



At- this fttige of the pr.ocefs,. as the, battery had required twic£ die, quantity of elecfiricity, 

 to produce the effect which had.before taken, place wlih a fmaJler qiuintity of coated fur- 

 lace, it became a qucflion whether the length of the circuit, which was fix feet on each fide, .„ 

 might have influenced the refults ;■ and alfo whether the (late of excitation had become lefs- 

 iiitenfe. For thefe reafons, the difpofitlon of the apparatus was altered fo that.the, circuiff. 

 ■with the battery was the- fame as had before been ufed with the jars; aiid the trial jar, 

 ■with Lane's eleflrometer, w»as agaifl applied to afcertaLn.tlrCippwer of the. machine- Five., 

 explofions wero afforded by 7| turns, as at- firft.: thts: experiment was twice repeated, atulv 

 fliewed that the aiTtion of the machine continued to be the fame as at firfl. 



Ih this new difpofitlon of the battery five inches of the wire were cxpofed to the explofion. ■ 

 No effedl was produced by I2 turns ; but by 21 turns the whole of the wire was difperfed- 

 in globules by a ftrong ignition. I fuppqfe that 20 turns might hav£ difperfed.^ it in ths^ 

 fame manner as in tlife firfl; expeririient.- 



Two inches afid'a half of the -vvire were theii placed in the circuit. This portion Wa&» 

 HOt affefted" by an jexplofion of 12 turns ; but by 13 turns it was ignited and broken by, 

 the diffipation of a globule or two. LaftJy, one inch of the wire, was ex.pofed to, the fhock j,- 

 it. was ignited, and partly difperfed in globules by laturns- 



The whole of thefe experiments employed upwards of three hours, during the greatcfl' 

 part of which time the machine wasln a<5Hon. At the. conclufion the trial jar was, applied :., 

 it exploded five times in a little more than eight turns. The trial was repeated twice, and 

 fcrvcs evidently to (how the fteadinefs of theexcitatign, which hjd diminiftied only about 

 -Vth part during this courfc of work. 



Upon a review ofnhe foi-egcing experiments, it iaobvlous that they woidd require to be 

 lepeated and extended, if the general courfe of Mr. Cuthbertfon's former proceffes were not 

 to be admitted in confirmation af thepofition, that equal quantities.of eledricity will ignite 

 and difperfe equal quantities of the fame wire, without requiring any particular adjuftment, 

 of the quantity of coated furface, provided the intenfity be confiderable. From the experi- 

 jnents with the battery it feem§ reafonable to conclude, that the quantities of eledrlcity re- 

 quired to produce like effe«^s upon wire will be greater, the lower the intenfity, when the 



quantitif 



