38 Mr. W. 



Cyclic 



Cyclohexane '31 



B. Hardy on 

 Compounds. 



Cyclohexane 



1.2. Methyl 



1.3. „ 

 1-4. „ 



Castor oil 

 Water .... 







Methyl cyclohexane ... 30 

 1.3. di Methyl cyclohexane '29 



Oyclohexanol '20 



1.2. Methyl cyclohexanol '28 



1.3. „ „ '25 



•35 



cyclohexanone 



•32 

 •35 

 •33 



•0* 



Triethylamine '30 







Tripropvlamine '26 



•33 



B. Influence of the Beilby Film. 



In 1903 Beilby described bow, in tbe process of burnishing, 

 or polishing, the substance of the solid actually flows so as to 

 cover the surface with a film of amorphous material. The 

 formation of the Beilby film can be readily followed on 

 bismutb, and in order to test its influence some measurements 

 of friction were made after it had been etched off by dilute 

 acid so as thoroughly to expose the coarse crystalline structure 

 of the metal. The following values were obtained : — 



Burnished. Etched. Ratio. 



Benzene '34 -39 "87 



Pyridene -33 '4 '83 



Ethyl alcohol -32 -39 "82 



Butyl xylene -27 37 '72 



Octyl alcohol -25 -36 '7 



Cyclohexanol -20 -33 '6 



The substances are arranged in the order of the value for 

 static friction of burnished faces. The values for etched 

 faces do not follow this order, whilst the ratios do. This 

 may be merely coincidence, but it raises questions which must 

 be reserved for discussion until more facts are available. 



C. Adsorption of Lubricants. 



The theory outlined in the first paper (this journal, ser. 6. 

 vol. xxxviii. p. 32 (1919)) embodies two propositions : the 

 first, that resistance to slipping is due to cohesion even when 

 a lubricant is present, and that a lubricant decreases friction 

 by partially or wholly masking the cohesive forces of the 

 solids; the second, that a lubricant maintains its position 

 against the normal pressure because its surface energy is a 

 function of the thickness of the layer. 



The capacity for decreasing friction, then, is a function of 

 the potential of the attractive forces between lubricant and 



