228 COMMANDER L. W. P. CHETWYND: EESULTS OF MAGNETIC OBSERVATIONS 



TABLE I. Corrections for Instrumental Differences. 



5. To reduce the observed values to a common epoch, the field observations were 

 compared with synchronous values derived from the Kew magnetograms, and the 

 differences as recorded at Kew between these latter values and the mean value for 

 1906 and 1907 were applied as a correction to the values at the field stations to 

 reduce them to the epoch 1st January, 1907. 



The comparisons were made by the Staff of the Observatory Department of the 

 National Physical Laboratory and the resulting differences supplied by Dr. CHREE, 

 F.E.S. 



6. A summary of the results of all the field observations is given in the following 

 Table II. : 



