332 Dr. R. D. Kleeman on Relations between the 



if the logarithm is taken to the base 10. The equation may 

 now be written 



%P?-pl)=T]og* 



Pc Z Pi 



(4) 



The mean values of E for a number of substances, given by 

 the above equation, and the corresponding values of 



T c 

 —^ — ^r„ , are given in Table II. The agreement between 



the two sets of values is fairly good. 

 From equations (1) and (4) we have 



(p\-f^ = ^T(pf-p^). .... (5) 



If we, as before, express the quantities in this equation in 

 terms of their critical values, we have 



w J-«J=6(^-fiJ^) (6) 



Equations (1) and (5) express approximately the relation 

 between the quantities p x , p 2 , and T, and equations (3) and 



(6) the relation between the quantities 



?7 1? ?i 2 , an 



d Tit 



Equations (1) and (5) are very useful. From equation (5) 



, p\ — pl \3/5 



we have p c = \ w-jm — w~ys ) , which may be used to calculate 



Table IV. 



Name of liquid, 



Ethyl oxide 



Octane 



Ethyl propionate . . . 



Pentane 



Benzene 



Heptane 



Hexane 



Carbon tetrachloride 



Iodo-benzene 



Bromo-benzene 

 Di-isobutyl ... 

 Ethyl acetate 

 Fluor-benzene 

 Carbon dioxide 

 Hexamethylene 

 Chloro-benzene 

 Methyl formate 



293 

 393 

 383 

 313 

 353 

 353 

 343 

 373 

 473 

 433 

 373 

 363 

 353 

 263 

 363 

 413 

 . 303 



Ethyl formate 333 



•7135 

 •6J68 

 •7823 

 •6062 

 •8145 

 •6311 

 •6122 

 1-4343 

 1-7079 

 1-2994 

 •6236 

 •8112 

 •9496 

 •9560 

 •7106 

 •9723 

 •9598 

 •86S9 



Pr 



•00187 



•0033 



•004739 



•00339 



•002722 



•001996 



•00337 



•01026 



•0 3 4400 



•005255 



•002967 



•004673 



•002885 



•0725 



•003759 



•004316 



•002225 



■003356 



pc 

 (Landolt & 

 Bornstein) 



•2604 



•2327 



•2860 



•2323 



•3045 



•2341 



•2344 



•5576 



•5814 



•4853 



•2366 



•2993 



•3541 



•464 



•2735 



•3654 



•3489 



•3150 



Pl~P2 1 

 a 1/3 a 1/3 I 



•2(561 

 •2243 

 ■3011 

 •2505 

 •3071 

 •2343 

 •2347 

 •5563 

 "5755 

 •4919 

 •2125 

 •3076 

 •3559 

 •4606 

 •2721 

 •3695 

 •3567 

 •3360 



T c 



T> 1/3 



(Landolt & 



*Pc 



Bornstein). 



3 



467-4 



484-8 



5692 



592-4 



545-4 



5801 



470-0 



489-8 



561-5 



569-4 



539-9 



5707 



507-8 



524-7 



556-1 



555-0 



721 



729-3 



670 



684-4 



543-8 



558-4 



522-5 



550 3 



559-5 



5750 



304-3 



3070 



553 



558-0 



633 



6+B8' 



487 



477-7 . 



503 



525-5 



