130 nature's teaching**. 



remain for centuries if man does not deface tnem. Such, for 

 example, are Caesar's camp, near Alder shot, and the fine camp 

 at Lyddington, in Wiltshire, almost every detail of which is 

 preserved. Roman camps are all constructed on the same 

 model, the general's place, or Praetorium, being in the centre, 

 whence he issued his orders, and the commanders under him 

 occupying the corners. Thus, no matter how he might be 

 shifted from one corps to another, every Roman soldier knew 

 his way about the camp without needing to see it, and could 

 tell at any moment where to find any officer. 



MOUND FORT. 



Other nations made their Forts circular, an example of which 

 I lately saw a few miles from Bideford, while others consisted 

 of nearly parallel lines, enclosures, and demi-lunes, like those 

 wonderful dykes near Clovelly, which occupy more than thirty 

 acres of land. One of the circular Forts is shown on the right 

 hand of the illustration. 



As time went on, stone took the place of earth, and the prin- 

 cipal object of the builder was to give considerable thickness 

 below, so as to resist the battering-ram, and great height both 

 to walls and towers, so as to be comparatively out of the reach 

 of the arrows and other missiles of the besiegers. 



For awhile, such castles were impregnable, and the owners 

 thereof were the irresponsible despots of the neighbourhood, 

 recognising no law but their own will, robbing, torturing, and 

 murdering at pleasure, and setting the king at open defiance. 

 When, however, the tremendous powers of artillery became 

 developed, the age of stone castles passed away. Height was 

 found to be equivalent to weakness, as the strongest tower in 

 existence could be knocked to pieces in an hour or two, and do 

 infinite harm within the fortress by its falling fragments. 



Fortification then returned to its original principles. Earth 

 took the place of stone or brick ; and at the present day, 



