22. Sale by trustee directed to sell within specified time.—Where a trustee directed to sell within a specified time extends such time the burden of proving, as between himself and the beneficiary, that the latter is not prejudiced by the extension lies upon the trustee, unless the extension has been authorised by a principal Civil Court of original jurisdiction. Illustration A bequeaths property to B, directing him with all convenient speed and within five years to sell it, and apply the proceeds for the benefit of C. In the exercise of reasonable discretion, B postpones the sale for six years. The sale is not thereby rendered invalid, but C, alleging that he has been injured by the postponement, institutes a suit against B to obtain compensation. In such suit the burden of proving that C has not been injured lies on B.