results have been published; according to the information given, the probable accidental error of the mean result (reduced to the sun's limb) was about 1″.6, so that no conclusion was permissible.
The principle of equivalence opened up the possibility of a general theory of relativity not confined to uniform motion, for it pointed a way out of the objections which had been urged against such an extension from the time of Newton. At first the opening seemed a very narrow one, merely indicating that the objections could not be considered final until the possibilities of complications by gravitation had been more fully exhausted. By 1913, Einstein had surmounted the main difficulties. His theory in a complete form was published in 1915; but it was not generally accessible in England until a year or two later. As this theory forms the main subject-matter of the book, we may leave our historical survey at this point.
