550 



Quartz cylhiders: axes i.. Date: August. 2, 

 Telescope West 



Reading scale 

 in m.m. 



66.8 

 66.8 

 67.0 

 67.0 

 67.0 

 66^92 



Telescope East. 

 67.2 

 67.2 

 67.3 

 67.4 



6772"8, hence E > W 0.36. 



The results are exhibited as a curve in fig. 3. The abscissae give 

 the hours of the observations. The temperature of the instrument 

 diminished in the course of the day a feu^ tenths of a degree. 



Quartz cylinders. Axes 1 1. Date: August. 5. 

 Telescope West Telescope East. 



Reading scale 

 in m.m. 



39.7 

 39.7 

 39.8 

 39.8 



39^5 



These results are represented in fig. 4. 



Quartz-axes ± [Aug. 2 cellar] 



40.0 

 40.2 

 40.1 

 40.1 



40.10, hence E > W 0,35 



These observations exhibit a difference of the readings for the 

 position of the torsion rod after rotation of the apparatus from the 

 E-W to the W-E position. Moreover it appears that it makes no 

 diference tvhether the cry stall ographic axes of the quartz cylinders are 

 parallel or crossed. At least this difference is only 0,36—0,35=0.01 mm. 



The constant difference of 0,35 mm. was traced to be probably 

 due to the asymmetrical, magnetic action of the heavy iron beams 

 of the cellar vault on the v^^eakly magnetic torsion rod of hardened 

 copper of the balance. A magnet placed in the neighbourhood of 

 the apparatus caused a small deviation. 



Tlie balance was then transferred to the vestibule, a place of rather 

 constant magnetic potential. The difference between the E-W and 



