178 DECLINE OF THE 



CHAP. VII. 



arising from the irruption of the barbarous tribes 

 which surrounded the empire. The new mines 

 along the borders of the Danube in Dacia, those 

 of Illyria, Dalmatia, and Thrace, were the first 

 to suffer from this ceruse, which the emperors, 

 either from the weakness of their forces, or the 

 exhausted state of their treasuries, were unable 

 to prevent. The workmen in the mines either 

 fell as captives into the hands of the invaders, 

 and were thus removed from the districts, or 1 

 they were induced by the sufferings they en- 

 dured to enlist with the Barbarians, and to aug- 

 ment their means of annoyance to the empire. 



By these events some of the mining provinces 

 became gradually depopulated, and in others 

 the workings were by degrees abandoned, as the 

 exhaustion of the products of the more precious 

 minerals had caused the expense of separating 

 them far to exceed the value that could be 

 extracted. This exhaustion of the more valua- 

 ble contents of the mines had produced the 

 abandonment of those in the east and in Spain; 

 where other nations had gathered the first-fruits, 

 and left to the Romans neither the first, the 

 second, nor the third harvests. From these well- 

 known circumstances, and from the silence of 

 all the writers of a later period concerning the 



1 See Gibbon's Decline and Fall,, cap. xxvi. p. 393, where 

 he describes the miners of Thrace conducting the Barbarians 

 to secret magazines of corn and cattle. 



