Art. 3.— IC. Sotome: 



screw, I made observations of polar stars at their greatest 

 elongations every summer and winter. The total numl)er 

 of determinations during the period amounted to 58. When 

 observing the polar stars in their eastern and western elongations, 

 I found a remarkable fact, viz. that the ]>ubbles of the two levels 

 attached to the zenith telescope moved gradually towards the south, 

 both in the eastern and the western positions of the telescope. 

 Moreover, the magnitude of displacement was larger in winter than 

 in summer, and it varied generally Avith the length of the ol)serva- 

 tion. This can be seen from the following table, in which the 

 first column is the date of observation, the second and third 

 columns the bubble displacements of the first and second levels in 

 units of division, the fourth the observed stars, the fifth the interval 

 ■of observation, and the sixth the temperature of the observing 

 room. 



Table I. 

 Telescope West. 



( + increase, — decrease) 



