Chemistry and Physics. 469 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. The Heedless Condition of Matter. — Brinkworth and 

 Martin, with apparent seriousness, have made a curious exten- 

 sion of the kinetic theory. Assuming that heat is due to molecu- 

 lar motion, they suppose a solid to be placed in an infinitely 

 strong and unyielding cylinder, made of a heat-conducting sub- 

 stance, and slowly compressed. As the compression proceeds the 

 molecules are driven closer together, heat is evolved, but this is 

 conducted away. Ultimately the molecules will be driven into 

 absolute contact and will be so tightly pressed, the one against 

 the other, as to be absolutely unable to move relatively to each 

 other. Therefore, in this condition the molecules can possess no 

 kinetic energy or relative motion of any description ; but, accord- 

 ing to the kinetic theory, the temperature of a body is measured 

 by the kinetic energy of its molecules. Here we are dealing 

 with a very remarkable case : we have a solid at the absolute 

 zero of temperature in the midst of a medium of much higher 

 temperature, and yet the solid (on account of the enormous pres- 

 sure to which it is subjected) is unable to take up the surround- 

 ing temperature, but persists in its heatless state. If the pressure 

 be released, the solid immediately regains the power of acquiring 

 heat irom neighboring bodies, and its temperature will rapidly 

 rise from absolute zero until it reaches that of the surrounding 

 material. It appears from the above to be a necessary conse- 

 quence of the molecular theory that at a very great pressure 

 matter must be reduced to a peculiar condition in which it will 

 not obey the law of thermal equilibrium. Now r the pressure 

 at which this remarkable physical condition becomes manifest 

 depends upon the nature of the material, and will alter with the 

 temperature. As the temperature falls and the kinetic energy of 

 the molecules becomes less, a smaller pressure will suffice to 

 bring the molecules into contact. At ordinary temperature the 

 pressures will be terrific — probably beyond our experimental 

 power ; but at very low temperatures a moderate pressure w T ill 

 probably suffice to bring about this condition. Pressure, how- 

 ever, is made up of two parts, external and internal, the latter 

 being due to molecular attraction ; therefore, even if the external 

 pressure be zero, yet the molecules will be under a very consider- 

 able internal pressure, and the very interesting conclusion must 

 be drawn that to this internal pressure alone there must corre- 

 spond a definite temperature above absolute zero at which this 

 new condition is induced in a substance. The usual assumption, 

 therefore, that all substances can be cooled continuously and uni- 

 formly down to the absolute zero, is incorrect. At a minimum 

 temperature depending upon the total pressure, the temperature 

 of each substance will drop more or less abruptly and of its own 



