If the assets were not sufficient to satisfy all the legacies at the time of the testator’s death, a legatee who has not received payment of his legacy must, before he can call on a satisfied legatee to refund, first proceed against the executor or administrator if he is solvent; but if the executor or administrator is insolvent or not liable to pay, the unsatisfied legatee can oblige each satisfied legatee to refund in proportion.