DETERMINATION OF DEFLECTION OF LIGHT BY THE SUN'S GRAVITATIONAL FIELD. 315 



results. Of the other series, only the exposures actually used in the reductions are 

 given. 



LIST of Plates. 

 Check Field (R.A. 14h. 12m. 47s., Declination +20 30') 



NOTES. 



Column 1. The letter is marked on the original plates (preserved at Cambridge Observatory). The 

 number refers to the exposure, disregarding exposures taken without the 8-inch stop. 



Column 2. The co-ordinates of Oxford Observatory are 5m. 3s. W., 51 46' N., and of the site at 

 Principe, 29m. 32s. E., 1 40' N. 



Column 4. The mid-instant of the exposure is given. Times for check plates at Principe were only 

 noted roughly. Times for the eclipse plates are deduced from the calculated time of totality, the interval 

 from the end of one exposure to the beginning of the next being assumed uniform. 



Column 7. Readings at Principe were taken with an aneroid recording instrument, and therefore 

 automatically reduced to the latitude of England. The barometer during our visit was practically constant 

 except for a regular semi-diurnal wave of amplitude about 0-05 in. 



Column 9. Brand of Plate : S. = Imperial Sovereign, S.S. = Imperial Special Sensitive, S.R. = Ilford 

 Special Rapid, E. = Ilford Empress. Backed plates were used at Principe. 



VOL. CCXX. A. 



2 X 



