84 



the viscosimeter wa? turned roimd, to drive the remaining liquid 

 out of the capillary. Only one determination was successfVd. We 

 hoi)e later on to be able to publish more extensive determinations 

 at low temperatures. 



Our results are given in the table. 

 The liquid-densities were measured by a dilalometer. 



corrected 

 235.2 

 258.2 

 291.5 

 352.3 



The method of calculation of r^ from the data is made clear bj 

 the following example. 



The viscosimeter when tilled weighed 16.78 gr. and empty 

 14.26 gr. 



The weight of the butane was therefore 2.52 gr. with a volume 

 of 4.20 ccm. 



The time of tlow of 4.20 ccm. water at 0° is 1504.0 sec. (accor- 

 ding to table on page 80; of the butane 291.8 sec. 



Corrected for capillai-ity these times become 1499.8 and 291.5. 



O.GOl X 291 5 ^^^ „ 



.,. = 0.01778^) therefore ,, ^ 0.01778 ^^^^^^ ^ ^^^^^^^ ^ 0.00207. 



Thorpe and Rodger (p. 590) give for the viscosity at the boiling 

 point for 



normal pentane ij X ^^^^ 200 isopentane 203 



„ hexane 204 isohexane 205 



,, heptane 199 isoheptane 198 



,, octane 198 



As the boiling point of butane is just below 0°, the value we find 



for ij corresponds well with that for the other hydrocarbons. 



Physics. — "O/i the law of the partition of enenjij." III. By Prof. 

 J. D. VAN DER Waals Jr. (Communicated by Prof. J. D. van 



DER Waals Sr.). 



§ 9. The distribution in conjiguration. 



In § 7 of my preceding note on this subject I have called attention 

 to the deviations of Boltzmann's law for the distribution in confi- 

 guration, but then I did nol give a possible formula for it. Nor can 

 1 give a formula for the general case now. I will however tj-y for 



ij Thorpe and Rodger 1. c. p. 449. 



