( 1258 ) 
gee. 
limiting value is equal to ——. With rise of 7’ this quantity decreases. 
5 ; 
But we have concluded to such a value of n, > f, that the factor 
of a is positive, even at Ty. 
If we take n=9, then z=—= 0,023 at O° degrees, and « would 
rise at ascending temperatures, and assume the following values: 
400° - 4102-4208 14501 add ASOR AGO age 
z 0,088 0,095 0,103 0113 012. 0122 O13 0,136 
These values of « do not deviate too much from the formula: 
EL 1—m 
log,, — = 1,2 —— 
: a“ m 
and then point to a value of 2, = 0,16. 
But this relation cannot hold in the immediate neighbourhood of 
mei. Then the curve, which represents the course of z as function 
of m, would intersect the line m—1 at an acute angle, whereas it 
must touch it. This follows also from the differential equation, 
ry 
: ; T de 
according to which — ZT depends on two terms, one of which is 
& OC 
1 
8 dv T dv , . F +t t t ] da AN 
some times — ——. Ss —— IS Mmanlieiy reat a / = / … — — W 
v dl ii v dT en = sdT ven 
7 
; T dv 
also be infinitely great. The factor of — = 
Uv 
the curvature of the z-line will be less broad at the vapour side of 
the top — and w,—=0,16 may be considered as an approximate 
value. 
I have subjected other substances investigated by SypNey Youne 
to such an examination — and on the whole I have found a similar 
series of values for « with small differences in the course, which 
may later on yield material for investigation. 
For normal pentane, which seems to have been investigated with 
particular care, as determinations have been made up to the imme- 
diate neighbourhood of 7, I have represented the shape for « quite 
accurately, and tested it by the experimental determinations. The 
critical temperature is given equal to 197,2° and measurements have 
been made at: 
1967; 196.5" 198 1972) and. VOTE 
The accurate form for x is the following: 
v oy) pe te ee ve (f—1) 1 = 
v—b v sm Overs n v—b v sm ( ==) 
The values of f I have taken equal to 7, that of s= 3,766, that 
is, however, small. So 
