2. BUT, secondly, as to the particular mode of inheritance, it in general corresponds with the feodal path of descents, chalked out by the common law in the succession to landed estates; yet with one or two material exceptions. Like them, the crown will descend lineally to the issue of the reigning monarch; as it did from king John to Richard II, through a regular pedigree of six lineal descents. As in them, the preference of males to females, and the right of primogeniture among the males, are strictly adhered to. Thus Edward V succeeded to the crown, in preference to Richard his younger brother and Elizabeth his elder sister. Like them, on failure of the male line, it descends to the issue female; according to the antient British custom remarked by Tacitus[a], "_solent foeminarum ductu bellare, et sexum in imperiis non discernere_." Thus Mary I succeeded to Edward VI; and the line of Margaret queen of Scots, the daughter of Henry VII, succeeded on failure of the line of Henry VIII, his son. But, among the females, the crown descends by right of primogeniture to the eldest daughter only and her issue; and not, as in common inheritances, to all the daughters at once; the evident necessity of a sole succession to the throne having occasioned the royal law of descents to depart from the common law in this respect: and therefore queen Mary on the death of her brother succeeded to the crown alone, and not in partnership with her sister Elizabeth. Again: the doctrine of representation prevails in the descent of the crown, as it does in other inheritances; whereby the lineal descendants of any person deceased stand in the same place as their ancestor, if living, would have done. Thus Richard II succeeded his grandfather Edward III, in right of his father the black prince; to the exclusion of all his uncles, his grandfather's younger children. Lastly, on failure of lineal descendants, the crown goes to the next collateral relations of the late king; provided they are lineally descended from the blood royal, that is, from that royal stock which originally acquired the crown. Thus Henry I succeeded to William II, John to Richard I, and James I to Elizabeth; being all derived from the conqueror, who was then the only regal stock. But herein there is no objection (as in the case of common descents) to the succession of a brother, an uncle, or other collateral relation, of the _half_ blood; that is, where the relationship proceeds not from the same _couple_ of ancestors (which constitutes a kinsman of the _whole_ blood) but from a _single_ ancestor only; as when two persons are derived from the same father, and not from the same mother, or _vice versa_: provided only, that the one ancestor, from whom both are descended, be he from whose veins the blood royal is communicated to each. Thus Mary I inherited to Edward VI, and Elizabeth inherited to Mary; all born of the same father, king Henry VIII, but all by different mothers. The reason of which