175 
1908-9.] Note on a Study of Polarisation. 
preliminary ones I have not thought it advisable to do so. I hope before 
long to repeat the experiments with more satisfactory precautions against 
the sources of error referred to above. 
The expenses of the above experiments were defrayed in part from the 
Tait Memorial Fund. 
(Issued separately April 12 , 1909 .) 
