408 l)r, J. R. Ash worth on the Theory of 



rounding temperature allowed the rate o£ cooling or heating 

 to be finely adjusted. 



In the second set o£ experiments a thick nickel wire was 

 folded several times parallel to itself, and the beating was 

 done by passing a current through a spiral of high resistance 

 wire surrounding it, and no current traversed the nickel ; the 

 required magnetic field was set np by the heating current, 

 which was either continuous or alternating, and in some 

 experiments by an electromagnet, the field of which, either 

 steady or alternating, was made to act on the nickel longi- 

 tudinally or transversely. The nickel was, as before, 

 surrounded by the porcelain jacket, and its temperature was 

 determined by a thermo-junction. 



In a third group of experiments a block of nickel was 

 used in the form of a short stout cylinder with a small 

 hole drilled half-way through it, into which the thermo- 

 junction fitted nicely, and this was put inside an earthenware 

 pot which could be heated by gas-jets. The magnetizing 

 field was applied by an electromagnet placed on the 

 outside. 



The experiments on iron were made on wires only, but in 

 all other respects the apparatus and the conduct of the ex- 

 periments were the same as with nickel. It will be sufficient 

 to give a brief summary of the results of a large number of 

 observations. 



Nickel. 



Method I. (Thin wire traversed by current.) 



Critical Temperature 

 in scale units. 



With steady field 1983 



With alternating field 19-72 



With no field 19-86 



Method II. (Thick wire surrounded with a Solenoid.) 



With alternating 'field 19*26 



With no field 19-35 



Method III. (Cylindrical Block.) 



With alternating field 1934 



With no field 19-50 



Iron. 



Method II. (Wire surrounded with a Solenoid.) 



With alternating field 39"89 



With no field 40-06 



The temperature of 19'90 scale divisions corresponds to 

 385° C, one-tenth of a scale division being approximately 

 2° C. The field, either steady or alternating, was not less 

 than 25 gausses. 



