These operate by electrostatic induction and convert mechanical work into electrostatic energy by the aid of a small initial charge which is continually being replenished or reinforced.
Bela endeavoured to strengthen his own monarchy by introducing the hereditary principle, crowning his infant son Emerich, as his successor during his own lifetime, a practice followed by most of the later Arpads; he also held a brilliant court on the Byzantine model, and replenished the treasury by his wise economies.
He replenished the treasury by a more equable and rational system of assessing and collecting the taxes.
But though the treasury was thus temporarily replenished and the army increased, the gentry who had been so generous at the expense of their richer neighbours would hear of no additional burdens being laid on themselves, and the king only obtained what he wanted by sacrificing his principles to his necessities, and helping the szlachta to pull down the magnates.
The state domains were exhausted by 1870, but were again replenished by the large confiscations which followed the Arab revolt of 1871.