328 C. G. KNOTT 



the " logarithmic rate " of change of resistance seems to be very 

 approximately inversely as the absolute temperature. In nickel and 

 iron, in which the law of the Thomson effect is peculiar, such a 

 simple relation between resistance and temperature does not hold. 



Electrical Properties of Hydrogenised 



Palladium. 



By 



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



Professor of Pliysics, Imperial University. 



This note is also an abstract of a paper, read before the Royal 

 Society of Edinburgh in July 1886, and now appearing in the 

 Transactions. It consists of two parts, the first being a study of the 

 electrical resistance of palladium at various stages of liydrogenisation, 

 and the second a study of the thermoelectric properties. 



It has been known for some time that the resistance of a palla- 

 dium wire charged with hydrogen at ordinary atmos])heric temperatures 

 increases at a rate almost strictly proportional to tlie amount of charge. 

 When fully saturated the resistance of the wire is about 1.7 times its 

 resistance in the pure state. The interesting question as to the eifect 

 of change of temperature on the resistance of hydrogenised palladium 

 seems, however, never to have been approached by former experimen- 

 ters. If a pretty strongly charged palladium wire be taken and 

 slowly heated, the resistance will be found to grow steadily up to a 

 temperature of 130° C. Above this temperature a somewhat more 

 rapid increase of resistance is generally observable until 200" C. is 



