360 



These values which have been selected IVom several which differ 

 considerably give; 



!l^=1228. • 



n 



15.5 



Determination of the Viscosity of butane vapour. 



The viscosi meter was connected to the butane-reservoir, and two 

 or three times washed out wdtli the vapour. Finally it was filled 

 with vapour, while the reservoir was cooled to — 8° C. At the 

 temperature of the room the vapour is then so far removed from 

 saturation, that irregularities owing to condensation in the capillary 

 need not be feared. 



Again the results may contain a small error owing to the uncer- 

 tainty of the drop-method used. 



7)1 = 1 .09 grms. 



2 3 4 



52.5 59.3 68.9 



The deviations from the straight line were much smaller than in 

 all the other determinations. 



The deviations are again upwards and more pronounced than in 

 the previous determination. 



a— .11. 6 = 59.40. 



Second observation at room-temperature. 

 7/1 = 1.09 



X 12 3 4 



t 47.0 53.4 60.8 68.3 



temp. 16.0. 



The deviations have increased and agree in magnitude with those 

 in the other observations 



a = .12. 6 = 45.74. 



