LOW-TEMPERATURE RESEARCHES 



and Olzewski have also been important, and it is not 

 always possible to apportion credit for the various dis- 

 coveries accurately, since the authorities themselves 

 are in unfortunate disagreement in several questions 

 of priority. But in any event, such questions of exact 

 priority have no great interest for any one but the 

 persons directly involved. We may quite disregard 

 them here, confining attention to the results them- 

 selves, which are full of interest. 



The questions investigated have to do with the phys- 

 ical properties, such as electrical conductivity, magnet- 

 ic condition, light-absorption, cohesion, and chemical 

 affinities of matter at excessively low temperatures. 

 It is found that in all these regards most substances 

 are profoundly modified when excessively cooled. 

 Thus if a piece of any pure metal is placed in an electric 

 circuit and plunged into liquid air, its resistance to 

 the passage of the electricity steadily decreases as the 

 metal cools, until at the temperature of the liquid it 

 is very trifling indeed. The conclusion seems to be 

 justified that if the metal could be still further cooled 

 until it reached the theoretical "absolute zero," or 

 absolutely heatless condition, the electrical resistance 

 would also be nil. So it appears that the heat vibra- 

 tions of the molecules of a pure metal interfere with 

 the electrical current. The thought suggests itself that 

 this may be because the ether waves set up by the vi- 

 brating molecules conflict with the ether strain which is 

 regarded by some theorists as constituting the electrical 

 "current." But this simple explanation falters before 

 further experiments which show, paradoxically enough, 

 that the electrical resistance of carbon exactly reverses 



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