1886.] 



Magnetisation in the Length of Iron Wires. 



205 



These currents having been determined, the final step was to repeat 

 the first observation of the .retraction produced by the fixed current 

 of 1-6 ampere, and thus to check the accuracy of the experiment. 

 The subtractions of the readings were then made, and if there had 

 been a difference of more than one scale division between the pre- 



Retraction with Current of 1'6 Ampere/ 





Iron wire 1*2 mm. 



Preliminary readings . -| 



121 la 

 127 1 6 



101 1* 

 107/ 6 



961 

 105/ y 



1081 

 118/ iU 











Iron strip. 



Preliminary readings . 



II} 9 

 70/ y 



It}** 





10 "1 20 

 30 J 



"is} 20 







Hard iron. 



Soft iron. 



Preliminary readings . 



901 



101 / 11 



92 111 

 103 j 11 



129 ill 



140/ 11 



1351 

 136/ 11 



601 

 68/ 8 



76 j 11 



liminary and the final result, it was my intention to repeat the series 

 of observations. This, however, was not found necessary in a single 

 instance. The actual figures as recorded in the note book are given 

 above, the differences being the numbers which appear in the last 

 line of the table in the paper. The agreement between the pre- 

 liminary and the final readings, when a number of experiments had 



at the moment of making an observation, and for a period of not more than half a 

 second at a time. 



* In eighteen pairs of observations with iron there was exact agreement sixteen 

 times and a difference of one scale division twice. With nickel the deflections wore 

 much larger, sometimes exceeding 100 divisions, and the agreement was not so close ; 

 but the discrepancy did not exceed two divisions. 



