photographs of the solar eclipse of 29th May, 1919. The relative discrepancies to be expected between the stellar photographs obtained during the eclipse and the comparison photographs amounted to a few hundredths of a millimetre only. Thus great accuracy was necessary in making the adjustments required for the taking of the photographs, and in their subsequent measurement.
The results of the measurements confirmed the theory in a thoroughly satisfactory manner. The rectangular components of the observed and of the calculated deviations of the stars (in seconds of arc) are set forth in the following table of results:
| Number of the Star. | First Co-ordinate. | Second Co-ordinate. | ||
|---|---|---|---|---|
| Observed. | Calculated. | Observed. | Calculated. | |
| 11 | -0.19 | -0.22 | +0.16 | +0.02 |
| 5 | +0.29 | +0.31 | -0.46 | -0.43 |
| 4 | +0.11 | +0.10 | +0.83 | +0.74 |
| 3 | +0.20 | +0.12 | +1.00 | +0.87 |
| 6 | +0.10 | +0.04 | +0.57 | +0.40 |
| 10 | -0.08 | +0.09 | +0.35 | +0.32 |
| 2 | +0.95 | +0.85 | -0.27 | -0.09 |
(c) Displacement of Spectral Lines towards the Red
In Section XXIII it has been shown that in a system which is in rotation with regard to a Galileian system , clocks of identical construc-
