204 



Mr. W. B. Hardy on 



way with molecular weight, but that there is no funda- 

 mental relation between viscosity and Jubrication is shown 

 by the following figures : — 



Viscosity at 20°. Static friction. 



Carbon tetrachloride 



Chloroform 



Acetic acid 



Octyllic acid 



Benzene 



Toluene 



Benzyl alcohol 



•0O96 

 •0056 

 •0122 

 •0575 

 •0065 

 •0058 

 •0558 



•43 

 •30 

 •40 



•19 

 •39 

 •28 

 •31 



-Fier. 1 . 



- 



• t3 W H) 2 

 C * H 6» I2CH(0H)» 



C,M c C0OH 



W« ch ■ CHof— 6 5 



C 6 H A (0H)C00H 



■ 



e C 1Q H 7 0H 



C H-COOH 

 W C00H) 2. ' 





w- .w chcV. u: 



p Cymene 



e C H 



io a 



W0OC 2 H 5 o 



c 6 h 5 :ch:ch-cooc 2 m 5- 



- 



C 6 H , 2 ' C 6 H 1|C H 3 . 6 S 2 5 •C 6 H 5 CH 2 OH 



- H CH m 13 C H (CH > Xy ' en ° »'Z c c H,nCH,0H 



CgHgCHXH-COOH 



C 6 H B -GH z CH 8 C00C e H s 8 





CH-OH «WV -WW" 





THYMOL* 



MENTHOL C i4 M IO* 















•C 6 H 5 SH 





CARVACROL 





C 6 M U° H 











RING COMPOUNDS 

 l l i i 1 i 



1 1 



1 1 



Fig-. 2. 



30 40 50 60 70 BO 90 100 



20 130 140 150 160 170 ISO 190 200 210 220 230 240 



Fluidity of the lubricant has no constant significance, 

 as indeed might be expected on the surface-energy theory 

 of lubrication. The curves for acids, alcohols, and paraffins 

 show no break where with increasing molecular weight 

 the lubricant becomes a solid at the temperature of 

 observation. Compare also benzene, naphthalene, and 

 anthracene ; menthone and menthol; thymol and carvacroh 





