*52. Sources: the Prerogative.*--Vested in the crown is, in the last analysis, an enormous measure of authority. The sum total of powers, whether or not actually exercised by the sovereign immediately, is of two-fold origin. There are powers, in the first place, which have been defined, or conferred outright, by parliamentary enactment. Others there are, however--more numerous and more important--which rest upon the simple basis of custom or the Common Law. Those powers which belong to the statutory group are, as a rule, specific and easily ascertainable. But those which comprise the ancient customary rights of the crown, i.e., the prerogative, are not always possible of exact delimitation. The prerogative is defined by Dicey as "the residue of discretionary or arbitrary authority which at any time is legally left in the hands of the crown."[68] The elements of it are to be ascertained, not from statutes but from precedents, and the sources of it, as enumerated by Anson, are (1) the residue of the executive power which the king in the early stages of English history possessed in all of the branches of government; (2) survivals of the power once accruing to the king as the feudal chief of the country; and (3) attributes with which the crown has been invested by legal theory, e.g., the attribute of perpetuity popularly expressed in the aphorism "the king never dies," and that of perfection of judgment, similarly expressed in the saying "the king can do no wrong."[69] The most considerable element in the prerogative is that which Anson first mentions, i.e., the power which the king has carried over, in the teeth of the popularization of the governmental system, from days when the royal authority was not hedged about as since the seventeenth century it has been. It is further to be observed that no inconsiderable portion of the royal powers as they exist to-day represent original prerogative worked over and delimited by parliamentary enactment, so that in many instances it becomes difficult to determine whether a given power exists by virtue of a statute, by which it is to be regarded as absolutely defined, or (p. 053) by virtue of an anterior prerogative which may be capable of being stretched or interpreted more or less arbitrarily. Nominally, the sovereign still holds by divine right. At the head of every public writ to-day stand the words "George V., by the Grace of God of Great Britain and Ireland King." But no principle of the working constitution is more clearly established than that in accordance with which the prerogatives of the crown may be defined, restricted, or extended by the supreme legislative power. Among prerogatives once claimed and exercised, but long since rendered obsolete by prohibitive legislation may be mentioned those of imposing taxes without parliamentary consent, suspending or dispensing with laws, erecting tribunals not proceeding according to the ordinary course of justice,