If the ulterior bequest be not valid the original bequest is not affected by it.
     Illustrations
     (i) An estate is bequeathed to A for his life with condition super-added that, if he shall not on a given day walk 100 miles in an hour, the estate shall go to B. The condition being void, A retains his estate as if no condition had been inserted in the will.
     (ii) An estate is bequeathed to A for her life and, if she do not desert her husband, to B. A is entitled to the estate during her life as if no condition had been inserted in the will.
     (iii) An estate is bequeathed to A for life, and, if he marries, to the eldest son of B for life. B, at the date of the testator's death, had not had a son. The bequest over is void under section 105, and A is entitled to the estate during his life.