Cossacks and the Charkars of eastern Mongolia, we have a large body of men living in the same arid grassland, leading the same pastoral life, and carrying on the same kind of warfare as the nomadic marauders whose pillaging, cattle-lifting raids they aim to suppress. The imperial orders to the Charkars limit them strictly to the life of herdmen, with the purpose of maintaining their mobility and military efficiency. So in olden times, for the Don Cossacks agriculture was prohibited on pain of death, lest they should lose their taste for the live-stock booty of a punitive raid. A still earlier instance of this utilization of border nomads is found in the first century after Christ, when the Romans made the Arabian tribe of Beni Jafre, dwelling on the frontier of Syria, the warders of the eastern marches of the Empire.[397] [Sidenote: Lawless citizens deported to frontiers.] The advancing frontier of an expanding people often carries them into a sparsely settled country where the unruly members of society can with advantage be utilized as colonists. After centralized and civilized Russia began to encroach with the plow upon the pastures of the steppe Cossacks, and finally suppressed these military republics, the more turbulent and obstinate remnants of them she colonized along the Kuban and Terek rivers, to serve as bulwarks against the incursions of the Caucasus tribes and as the vanguard of the advance southward.[398] This is one principle underlying the transportation of criminals to the frontier. They serve to hold the new country. There these waste elements of civilization are converted into a useful by-product. They may be only political radicals or religious dissenters: if so, so much the better colonial material. The Russian government formerly transported the rebellious sect of the Molokans or Unitarians to the outskirts of the Empire, where the danger of contagion was reduced. Hence they are to be found to-day scattered in the Volga province of Samara, on the border of the Kirghis steppe, in the Crimea, the Caucasus, and Siberia, still faithful and still persecuted.[399] Since 1709 the Russian advance into Siberia has planted its milestones in settlements formed of prisoners of war, political exiles, and worse offenders.[400] Penal colonists located on the shores of Kamchatka helped build and man the crazy boats which set out for Alaska at the end of the eighteenth century. China settles its thieves and cheats among the villages of its own border provinces of Shensi[401] and Kansu; but its worst criminals it transports far away to the Hi country on the western frontier of the Empire, where they have doubtless contributed to the spirit of revolt that has there manifested itself.[402] [Sidenote: Drift of lawless elements to the frontiers.]