534 



Mr. V. J. Blyth on the Influence of 



bars german-silver-iron junctions were soldered. After the 

 distribution of temperature had become steady, the current 

 flowing but generating no field, the junction readings were 

 taken, and then again some time after the field had been 

 excited. The generation of the field produced a rise of tem- 

 perature at the top of the magnetized bar of 2'2 per cent, in 

 the case of iron and 2*8 per cent, in the case of bismuth. In 

 the actual experiments time readings were taken of the tem- 

 perature at the top end of a bar whose lower end was fitted 

 hard into the copper block of the steam-chamber, the tempe- 

 rature being initially atmospheric. By drawing curves of 

 these readings the following results were obtained, the material 

 being mild steel and the field 51 c.G.s. : — 



Magnet off; rise of temp, in 20 min., 144 div. j Percentage decrease of 



on; „ „ 20 „ 138 „ J conductivity 4'2 



20 „ 211 „ 1 



off; 



20 



203 



3-8 



By a similar method a rod of soft iron, 6 in. long and 

 5/8 in. in diameter, was tested both for longitudinal and 

 transverse fields. But in this case thermo-junctions were 

 not used, the temperatures at the top end of the rod being 

 obtained from a mercury thermometer which rested in a 

 glass tube containing mercury attached to the top of the rod : 

 the top of the rod was tinned and amalgamated so as to be 

 in good thermal contact with the mercury. The longitudinal 

 field was supplied by a solenoid which was not anti-induc- 

 tively wound, but the heating of the thermometer by the 



Longitudinal field ; giving induction 16,000 C.G.s. 



Initial 

 Temperature. 



Eise of Temp, in 20 min. 



Difference. 



Percentage 

 Diminution. 



Magnetism off. 



Magnetism on. 



15-3 



29°7 C 



26°-9 



2-8 



9-4 



19-25 



28-4 



Rise in 



25-0 

 15 min. 



3-4 



12-0 



266 



21-6 



19-4 



2-2 



10-2 





Transverse field ; 78i 



)0 C.G.S. 







Rise in 20 min. 







13-2 



327 



3235 



•35 



1-07 



143 



321 



31-6 



•5 



1-56 



15-8 



320 



31-7 



•3 



•94 



