o8u Mr. J. N ,new^aer%i ia powerful Form 



through an interval of 0*5 of an inch, the jar was really as fully 

 charged as when charged in the ordinary way. I therefore in- 

 stituted a set of experiments which have developed some curious 

 and interesting results, and which, as far as I know at present, 

 are quite new. 



6. I introduced between the secondary terminals of the coil a 

 thermo electrometer in connexion with a Lane's discharger, but 

 although I varied the length of the sparks from to 1 inch, no 

 heating effect was produced upon the wire in the instrument. ^ 



7. 1 connected the coatings of an insulated Leyden jar, con- 

 taining about 3| square feet of surface, respectively with the two 

 terminals of the coil, and completed the circuit of the jar by a 

 thermo-electrometer in connexion with a graduated Lane's dis- 

 charger. On causing a rapid series of discharges to pass, the 

 fluid instantly rose in the stem and remained fixed pretty perma- 

 nently at nearly 100 degrees, or about one hundred times higher 

 than it would have risen with a single discharge from the same 

 jar with the ordinary electrical machine. The platina wire hang- 

 ing in the cylinder of the electrometer was thrown into the most 

 energetic vibration during the passage of the sparks, so as to 

 become crippled in several places. 



8. The thermo-electrometer was removed, and a piece of very 

 jfine iron wire, about 4 inches long, placed between insulated for- 

 ceps, was substituted for it in the circuit. On passing the dis- 

 charges, the wire became blue, vibrated rapidly, and crippled in 

 several places; and whilst occasionally suspending and repro- 

 ducing the action of the coil^ the wire suddenly melted at one of 

 the crippled places,; .;'';,* j "^ ,^ _ ' 



9. Another piece of the same wire/ about 3 inches in length, 

 was next introduced, and on passing the discharges it instantly 

 T)ecame red-hot through nearly its whole length and fused into 

 globules. The experiment was repeated with shorter pieces with 

 nearly the same results, the wire sometimes fusing throughout 

 .its whole length, and sometimes bfeakiijg ^ into fragments par- 

 tially burnt. , ( " v I , ^^f'.'^.T ^? '^, . ' ' 



10. The foregoing rematt able changie^iii tti^iheVm^l character 

 of the current when intercepted and, as it were, measured out by 

 the jar, induced the following experiment : — The thermo-electro- 

 meter was introduced into the circuit of the jar as before, and two 

 other thermo-electrometers were introduced into the portions of 



,the circuit leading from the terminals of the coil to the coatings 

 of the jar. By this arrangement, the current which charged the 

 Jar had to pass through these electrometers in its course. On 

 I setting the machine in action, the electrometer which completed 

 '^the circuit of the jar indicated the same thermal effect upon the 

 included wire, whilst the other two electrometers were not in the 

 slightest degree affected, clearly showing a marked difference 



