(1) The right of preemption in respect of agricultural land and village immoveable property shall vest (a) where the sale is by a sole owner,FIRST, in the son or daughter or son 's son or daughter 's son of the vendor; SECONDLY, in the brother or brother 's son of the vendor; THIRDLY, in the father 's brother or father 's brother 's son of the vendor; FOURTHLY,. . . " No doubt, the son and the other members of the family would not have been entitled to a present interest in the property alienated and consequently would not have a right to prevent the alienation (in which event, however, it is needless to add that a right to preempt wan wholly unnecessary as a means of preserving the property), but they would have a legitimate expectation of succeeding to the property an expectation founded on and promoted by the consciousness of the community.