3. A third rule reſpecting remainders is this; that the remainder muſt veſt in the grantee during the continuance of the particular eſtate, or eo inſtanti that it determines[1]. As, if A be tenant for life, remainder to B in tail; here B's remainder is veſted in him, at the creation of the particular eſtate to A for life: or, if A and B be tenants for their joint lives, remainder to the ſurvivor in fee; here, though during their joint lives the remainder is veſted in neither, yet on the death of either of them, the remainder veſts inſtantly in the ſurvivor: wherefore both theſe are good remainders. But, if an eſtate be limited to A for life, remainder to the eldeſt ſon of B in tail, and A dies before B hath any ſon; here the remainder will be void, for it did not veſt in any one during the continuance, nor at the determination, of the particular eſtate: and, even ſuppoſing that B ſhould afterwards have a ſon, he ſhall not take by this remainder; for, as it did not veſt at or before the end of the particular eſtate, it never can veſt at all, but is gone for ever[2]. And this depends upon the principle before laid down, that the precedent particular eſtate and the remainder are one eſtate in law; they muſt therefore ſubſiſt and be in eſſe at one and the ſame inſtant of time, either during the continuance of the firſt eſtate or at the very inſtant when that determines, ſo that no other eſtate can poſſibly come between them. For there can be no intervening eſtate between the particular eſtate, and the remainder ſupported thereby[3]: the thing ſupported muſt fall to the ground, if once it's ſupport be ſevered from it.
It is upon theſe rules, but principally the laſt, that the doctrine of contingent remainders depends. For remainders are either veſted or contingent. Veſted remainders (or remainders executed, whereby a preſent intereſt paſſes to the party, though to be enjoyed in futuro) are where the eſtate is invariably fixed, to remain to a determinate perſon, after the particular eſtate is ſpent. As
