140 GOVERNMENT WORKING CHAP. iv. 



water from the mines, and the machines and im- 

 plements for extracting what could not be kept 

 out, were all contrived to answer temporary pur- 

 poses commensurate with the length of the period 

 for which they were Jet to farm. To prevent 

 this premature exhaustion, in some instances 

 the censor limited the number of slaves to be 

 employed, and shortened the term of the leases ; 

 but these regulations seem either to have been 

 evaded or at least ineffectual. 



During the continuance of the republic, as 

 the mines did not improve in productiveness, 

 they gradually deteriorated, but so slowly that 

 their retrocession was not very striking till 

 Rome fell under a despotism, and a new state 

 of things with new institutions roused attention, 

 and directed it to the declining state of that de- 

 partment. 



It is not clear under which of the emperors 

 the alterations were made ; but soon after the 

 abolition of the republic, the mines were all 

 taken from the farmers, and the administration 

 of them intrusted to officers of different ranks, 

 who, upon a regular system, conducted the 

 working of them for the sole benefit of the em- 

 peror. By this change the subterraneous works 

 were more substantially and durably executed, 

 and the exhaustion of the mines did riot advance 

 at so rapid a pace as before. But the expendi- 

 ture was increased without a correspondent in- 



