MUM

(Lat.) In Ancient Sculpture, a tomb made reception of Ihe remains of two persons. in Gunnery, is the difference between the of the base ring at the breech of a gun am of the ring at Ihe s<vell of the muzzle. A place where medicines are mad< distributed; but used more generally for a cliarita where the poor are supplied with medicines advice. Insliiutions of this nature are of comparatively recent oriein; though they are now to be met will. town of any importance both in this country and Continent In London there are one or more diseach district; and to every dispensary there attached one or more physicians, surgeons, and whose duty it is respectively to prescribe and medicines to the poor, and to visit them in their houses in the event of their being too ill to attend personally at the institution. In most cases dispensaries are by voluntary contributions. In Law, a licence granted by the to a clergyman within his diocese to omit some particular of his duly; as, to hold two or more benefices, or out of his parish. The name is peculiar to ecclesiastical law, and was formerly applied to the licences by Ihe papal authority for several purposes; as, to within the prohibited degrees, Sec. A word synonymous with Pharmacopoeia (which see); signifying a book which describes the preparation, and composition of medicines. In Optics, a term used to denote the separation of the constituent rays of linht when decomposed by the prism. In consequence of the unequal of the different rays, a beam of light admitted a small hole or slit in the shutter of a darkened and refracted by pa ing through a prism, forms an image or spectrum; the red rays, which are Ihe refracted, occupying one end of the spectrum, and the rays, which suffer the greatest refraction, occupying end. The rays therefore, after refraction, are no parallel; so that the index of refraction (or the ratio sine of incidence lo the sine of refraction) is different ray; and Ihe difference of the indices for the extreme rays is called the dispersion of the light. Isaac Newton, who first examined the prismatic colours, was led by some imperfect experiments to suppose dispersion proportional to the refraction; but it was discovered that although the colours in spectra form by prisms of different substances are always arranged same order, they do not occupy the same relative a prism of flint gla , for example, giving prop or le red and more violet than a prism of crowr; and thatZ suD stances, for which the index of refrac [s. 367]