947 
Cae oe 2 : Mags nour mA 
P =e ff (ee = ta) r‘sin0, sind, dr dO, dO, dp . (13) 
7 0 0 0 
Developing into a series of ascending powers of kh, with neglect 
of terms with a’ etc., we find P’ to be split up into: 
Pa EY a ser vent eae meee €) 
where ‚P’ may be taken from Leiden Suppl N°. 39a. After inte- 
gration en respect to 7 we find: 
nn 20 
== zeef ff x 1 — ah WL sien vend, „sin0,d dÔ,dp.(15) 
000 , 
Performing this integration we obtain 
Fens Fae olan ea OA abe (16) 
= a: Av) rs pb a oe st 
and then *) 
US LA SPE FEE „heil tje Go)”. el eer a) 
Arg 5 3 
These terms added to ,B of the Leiden Suppl. N°. 39a finally 
give: 
ded 
B= jn. 0") 1 — 1,0667 (hv)? + 0,1741 (hv)... — 
ts 24 ho [1 + 1,067 (hv). . - ] (18) 
§ 4. Conclusions. In the first place we may remark, that for a 
strong validity of the law of corresponding states the same value of 
a 
— would be required for different gases. 
5 
With DeBijr we derive the value of a from the molecular refrac- 
tion (P,) for A==o, while the values of o are taken from the 
Leiden Suppl. N°. 39a for H,, from the preceding Communication 
(N°. 6a) for O, and for N,. In this way we obtain: 
| Po 0 
hydrogen | 2,03 2,32 XxX 10—8 
oxygen | 3,98 2,65 “ 
nitrogen | 4,34 2,98 - 
1) The first term of this result corresponds to a value for the VAN DER WAALS 
attraction constant a that perfectly agrees with that Bn by DeBuje (l. c. 
equation (18)). 
