Listed buildings in Lancaster, Lancashire century. The town stands at the lowest crossing of the River Lune, and received its first borough charter in 1193. In addition to being a market town, it became the judicial centre of the county of Lancashire, the castle being converted to serve this purpose in the 18th century. Also in the 18th century, in order to trade with the Americas, St George's Quay, with its warehouses and houses, was developed. Towards the end of that century the Lancaster Canal was built, linking the town with Preston. And in the 19th century railways came to the town, including what is
Spherical lune the second half great circle has moved a full circle, and the lune in between covers the sphere as a spherical monogon — the area formula for the spherical lune gives 4π"R", the surface area of the sphere. A hosohedron is a tessellation of the sphere by lunes. A n-gonal regular hosohedron, {2,n} has "n" equal lunes of π/"n" radians. An "n"-hosohedron has dihedral symmetry D, ["n",2], (*22"n") of order 4"n". Each lune individually has cyclic symmetry "C", [2], (*22) of order 4. Each hosohedra can be divided by an equatorial bisector into two equal spherical triangles. The visibly lighted