ON THE ANTIQUE HOUR-LINES. 77 



Some fragments of ancient dials are also published by Gr.e- 



vius *. 



Except the table of Palladius, the instruments above men- 

 tioned are each made for an unvarying azimuth. In the de- 

 scription of the antiquities of Herculaneum f, there is repre- 

 sented and explained a dial whose azimuth is changeable, to 

 suit the hour and the different declinations of the sun. It is 

 drawn on an irregularly curved surface of bronzfc, and the de- 

 clinations are marked with the Roman names of the months. 



The ancient names of different kinds of fixed and moveable 

 sun-dials, with the names of their inventors, are given by Vi- 



TUUVIUS. 



Something respecting the time of the first introduction of 

 gnomonic instruments, is to be collected from Greek and Ro- 

 man authors. The ancient inhabitants of Egypt appear to 

 have cultivated astronomy at a time prior to the earliest histo- 

 rical accounts ; and they have left a monument of their practi- 

 cal skill in that science, in the accurate meridional position of 

 these most ancient of human works the Pyramids. Portions 

 of their knowledge were diffused amongst the Hebrews and 

 Babylonians. 



The astronomical science of the Greeks was derived partly 

 from the Egyptians, and partly from the Babylonians J. Tha- 

 les || acquired his knowledge of astronomy and geometry 

 from the Egyptian priests, and introduced these sciences into 

 Greece. The gnomonic projection of the sphere is a branch 

 of the doctrine of spherical astronomy, and when applied to 



the 



* Gr*vii Thesaurus Antiquitalum Romanarum. 



-f- Le Pitture antiche d'Erculano, torn. ill. Napoli 1763. 



J Herodotus. 



jl Diogenes Laertius. 



