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APPENDIX A.

TABLE OF AZIMUTHS.

AZIMUTHS OF APPARENT SUNRISE AND SUNSET FOR LATITUDE OF CAMBRIDGE, 50°.13′52° 13′. Probably just a misprint, as the calculations have been done for the correct latitude.. N. Calculated by Rear-Admiral Boyle Somerville, C.M.G., F.S.A.

“To find the bearing by prismatic compass, at Cambridge, in 1932, add 12° to the above azimuths (sunrise or sunset). Annual change in variation (Cambridge) is −13′ (i.e. subtractive) at present.”

I am greatly indebted to Admiral Boyle Somerville for this valuable help for local investigation in this district. In giving it, he does not commit himself to any of my suggested conclusions. He adds the following explanation:—

“Remember that the above are apparent sunrises and sunsets, that is, they are the positions on the horizon at which the sun is actually visible, when rising or setting; and the azimuths are calculated for the sun’s centre, not for first emergence over the edge of the horizon (as Sir Norman Lockyer calculated, entirely unwarrantably) nor for the moment when it is seen standing entire on the horizon. We do not know which moment was observed by the ancients, and so the fairest thing is to take the mean, i.e., the sun’s centre.”