Subject to the provisions of section 12, on a transfer of property an interest therein may be created with the condition superadded that it shall cease to exist in case a specified uncertain event shall happen, or in case a specified uncertain event shall not happen.
     Illustrations
         (a) A transfers a farm to B for his life, with a proviso that, in case B cuts down a certain wood, the transfer shall cease to have any effect. B cuts down the wood. He loses his life-interest in the farm.
         (b) A transfers a farm to B, provided that, if B shall not go to England within three years after the date of the transfer, his interest in the farm shall cease. B does not go to England within the term prescribed. His interest in the farm ceases.