- MANUSCRIPTS. (Lat. maim scrip turn, written by the hand.) Literally, writings of any kind, whether on paper i or any other material, in contradistinction to such as are printed. Books were ge nerally written upon vellum, after the papyrus used in classical times had be come obsolete, until the general introduc tion of paper made from rags, about the 15th century after Christ ; and the finest and whitest vellum is generally indi cative of great age in a manuscript. The dearness of this material gave use to the practice of using old manuscript books on which the writing had been erased, and also to that of abbrevia tions. These were carried to excess in the 12th century, and from that time un til the invention of printing ; and for a long period subsequent to that invention, abbreviations were still in common use : in Greek printing they were usual until within the last fifty years. Of Latin MSS., those prior to the reign of Charle magne (A. D. 800) are considered ancient. Manuscripts of the early classical age were written on sheets rolled together. Illuminated manuscripts are such as are embellished with ornaments, drawings, emblematical figures, &c. illustrative of the text. This practice was introduced at a very early period ; for we find the works of Varro, Pomponius, Atticus, and others, adorned by illuminations. But it was chiefly employed in the breviaries and prayer-books of the early Christian church. The colors most employed for this pur pose were gold and azure. Illuminations were in a high state of perfection between the 5th and 10th centuries; after which they seem to have partaken of the barba rism of the middle ages, which threw their chilling influence over every de scription of art. On the revival of the arts in the 15th and 16th centuries many excellent performances were produced; but the art did not take deep root, and we believe the last specimen of illumina tion executed in England was Cardinal Wolacy's Lectionary, at Christ Church, Oxford.
MAP. (Lat. mappa.) A delineation of some portion of the surface of the sphere (terrestrial or celestial) on a plane. Terrestrial maps are geographic or hydro graphic. A map representing a small ex tent of country is called a topographical map.
Terrestrial Maps.. The object of a ter restrial map is to exhibit the boundaries of countries and the relative positions of their several parts. A perfect represen tation of a country should present all its parts, not only in their true relative posi tions, but also in their just proportions. This may be accurately done on a globe ; but as the earth's surface is spherical, it is impossible to represent any considera ble portion of it on a plane so that the dis tances of places shall retain the same pro portions which they have on the sphere, and geographers have accordingly had re course to various methods of delineations, all of which have their peculiar advanta ges in particular cases.
One method is to represent the points and lines of the sphere according to the rules of perspective, or as they would ap pear to the eye, having some assigned position relatively to the sphere and the plane of representation. This method gives rise to the different modes of pro jecting the sphere, of which the three principal arc the orthographic, the stere ographic, and the central. The method of projection answers very well when the surface to be represented is small, and the eye is placed perpendicularly over it ; but when it embraces a considerable por tion of the sphere, the parts near the ex tremities of the map are much distorted.
A second method is to suppose the sur face to be represented to be a portion of the surface of a cone, whose vertex is somewhere in the polar axis produced, and which either touches the sphere at the middle latitude of the surface to • be represented, or falls within the sphere at the middle latitude, and without it at the extreme parallels. The conical surface is then supposed to be developed on a plane (which it admits of being); whence this method is called the method of develop ment. Of this method there are various modifications : as that of Murdoch, who supposes the side of the cone to be paral lel to the tangent of the meridian at the middle latitude but to penetrate the sur face of the between the middle latitude and the extremities of the pro jected arc ; that of De Lisle, who assum ed the cone such as to intersect the sphere in the two parallels equally distant from the extreme and middle latitudes ; that of Euler, who placed the apex of the cone at a determinate distance beyond the pole. A third method is to lay down the points on the map according to some as sumed mathematical law, the condition to he fulfilled being that the parts of the spherical surface to he represented, and their representations on the map, shall be similar in their small elements. Of such methods the best known is .3ferca tor's Chart (which, however, may be pro duced also by development), in which the meridians are equidistant, parallel,straight lines, and the parallels of latitude are also straight linesperpendicular to the meri dians ; but of which the distances from each other increase in going from the equator in such a proportion as always to show the true bearings of places from one another.
Celestial Maps.—For the construction of his maps of the stars, the astronomer Flamstead adapted the following method: All the parallels on the sphere are repre sented by straight lines, and likewise one of the meridians ; namely, that which passes through the middle of the map. The parallels which are all perpendicular to this meridian have the same relative lengths as on the sphere, and consequent ly the degrees of longitude are represent ed in theirjust proportions; that is, are proportional to the cosine of the latitude. lf, therefore, the parallels be each divided into the same number of equal parts, a curve line drawn through the points of division will represent the meridians. By this method, any distance in the di rection of the parallels is equal to the cor responding distance on the sphere ; but it is evident that the map is much dis torted towards the extremities, in conse quence of the oblique directions of the meridians. Flanistead's method is some times used in geography for representing countries which lie on both sides of the equator, in which case the distortion is less. A modification of it, which consists in substituting arcs of circles for the straight lines representing the meridians, whereby their obliquity is diminished, is exteiteively employed in the construction of maps. The Society for the Diffusion of Useful Knowledge has adopted the gno monic projection for laying down their maps of the stars.