WITH us in England, the king's prerogative, so far as it relates to mere domestic commerce, will fall principally under the following articles: FIRST, the establishment of public marts, or places of buying and selling, such as markets and fairs, with the tolls thereunto belonging. These can only be set up by virtue of the king's grant, or by long and immemorial usage and prescription, which presupposes such a grant[o]. The limitation of these public resorts, to such time and such place as may be most convenient for the neighbourhood, forms a part of oeconomics, or domestic polity; which, considering the kingdom as a large family, and the king as the master of it, he clearly has a right to dispose and order as he pleases. [Footnote o: 2 Inst. 220.] SECONDLY, the regulation of weights and measures. These, for the advantage of the public, ought to be universally the same throughout the kingdom; being the general criterions which reduce all things to the same or an equivalent value. But, as weight and measure are things in their nature arbitrary and uncertain, it is therefore expedient that they be reduced to some fixed rule or standard: which standard it is impossible to fix by any written law or oral proclamation; for no man can, by words only, give another an adequate idea of a foot-rule, or a pound-weight. It is therefore necessary to have recourse to some visible, palpable, material standard; by forming a comparison with which, all weights and measures may be reduced to one uniform size: and the prerogative of fixing this standard, our antient law vested in the crown; as in Normandy it belonged to the duke[p]. This standard was originally kept at Winchester: and we find in the laws of king Edgar[q], near a century before the conquest, an injunction that the one measure, which was kept at Winchester, should be observed throughout the realm. Most nations have regulated the standard of measures of length by comparison with the parts of the human body; as the palm, the hand, the span, the foot, the cubit, the ell, (_ulna_, or arm) the pace, and the fathom. But, as these are of different dimensions in men of different proportions, our antient historians[r] inform us, that a new standard of longitudinal measure was ascertained by king Henry the first; who commanded that the _ulna_ or antient ell, which answers to the modern yard, should be made of the exact length of his own arm. And, one standard of measures of length being gained, all others are easily derived from thence; those of greater length by multiplying, those of less by subdividing, that original standard. Thus, by the statute called _compositio ulnarum et perticarum_, five yards and an half make a perch; and the yard is subdivided into three feet, and each foot into twelve inches; which inches will be each of the length of three grains of barley. Superficial measures are derived by squaring those of length; and measures of capacity by cubing them.