7(3 ON THE ANTIQUE HOUR-LINES, 



direction of the wind. Each of the eight dials is exposed to 

 one of the eight principal equidistant points of the horizon ; 

 two of the dials being parallel to the plane of the meridian. 

 The radii of the spheres from which the dials are projected, 

 vary ; the smallest being about eight inches, and the greatest 

 about twenty-five inches. In Stuart's Antiquities of Athens, the 

 building and the dials are represented in detail. 



The second example of the gnomonic lines of the ancients, 

 is in the valuable collection of antiquities brought from Athens 

 by the Earl, of Elgin. It consists of four vertical dials, two of 

 which are nearly south-east, and two nearly south-west in azi- 

 muth. They are inscribed on a block of white marble, which 

 bears the maker's name. The radius of the generating sphere 

 is about four inches and a half. 



The third example, is a projection of the antique hour-lines 

 on the inner surface of a cone whose axis is parallel to the axis 

 of the earth. It exists at Athens, and is figured by Stuart. 



The fourth is a small east dial, on a vertical plane, described 

 bv Delambre. It was found at Delos. The radius is half an 



inch. 



The fifth is a piece of Roman workmanship, figured by Bois- 



sard *. It is composed of five dials on the upper part of a 

 squared block of marble ; three of the vertical sides of which 

 are covered with an ancient Roman agricultural calendar. In 

 like manner, the treatise of Palladius de Re rustica, which is 

 a set of agricultural directions for every month, contains a gno- 

 monic table, shewing the length of a man's shadow for each 

 month, and for a climate in Italy. 



Some 

 * Boissardi Antiquitates Roman*. 



