Electrical Resistance of Nickel at High 



Temperatures. 



By 



Cargill G. Knott D. Sc. (Edin.) F. R. S. E. 



Professor of Physics, Imperial University. 



This note is an abstract of a paper wliicli is being published in 

 the Transactions of the Eoyal Society of Edinburgh. The ex- 

 periments were made in the Laboratory of the Imperial University 

 of Japan, and carried out in part by Messrs. Hirayama and Sane- 

 yoshi, IVth year students of Physical Science. The object was to 

 find if nickel was similar to iron in having any peculiarity as regards 

 resistance change at or about the temperature at which the very 

 striking thermoelectric change occurs. As shown first by Tait,* 

 iron and nickel are exceptional amongst metals in having what is 

 technically called an abrupt bend in their thermoelectric lines. In 

 fact it is possible to combine iron or nickel with other wires so as to 

 obtain two or more successive neutral points as the temperature of 

 one of the junctions is raised indefinitely; such a phenomenon can- 

 not be obtained with other metals substituted for the iron or nickel. 

 According to Tait's theory, this bend in the thermoelectric line means 

 an abrupt change in the sign of the Thomson Efiect. Some twelve 

 years ago it was discovered by Mr. (now Professor) C. Michie Smith 



* Transactions Eoyal Society of Edinburgh (1874.) 



