316 SIR F. W. DYSON, PROF. A. S. EDDIXGTON AND MR. C. DAVIDSON ON A 

 Eclipse Field (R.A. 4h. 19m. 30s., Declination +21 43') 



NOTES. 

 Columns 1 to 9. See previous page. 



The large proportion of Ilford Special Rapid plates used at the eclipse was due to 

 the fact that experience in developing the check plates showed that these suffered less 

 than the others from the high temperature of the water (78 F.). Ice was generally 

 available for the check plates through the kindness of Sr. GRAGEIRA ; but the supply 

 failed after the eclipse, and formalin was used to harden the films. This was un- 

 satisfactory except for the I.S.R. plates, and so plates P, S, T, W were brought home 

 undeveloped. The developing at Principe was done at night, and the drying was 

 accelerated by use of alcohol. 



The use of an 8-inch stop in front of the object-glass was suggested to us by 

 Mr. DAVIDSON, who showed that a great improvement of the images resulted ; it was 

 originally intended, however, to use the full aperture for part of totality. Early 

 measures of check plates made at Principe soon convinced us that the results from the 

 full aperture were greatly inferior, and we decided to rely entirely on the 8-inch 

 aperture. 



