The De Beers Company employs upward of eleven thousand African natives--Kafirs, they are called--working above and below ground. They come not only from the surrounding districts but from regions hundreds of miles away. All native laborers are kept in large walled enclosures, or compounds, which are covered with wire netting to prevent the laborers from throwing diamonds over the walls to confederates outside. Twelve such enclosures are owned by the De Beers Company, the largest of which occupies four acres and contains ample space for housing three thousand natives. On entering the service of the company each applicant must sign a contract to live in the compound and work faithfully at least three months. At the expiration of his contract he may leave or make another contract, as he wills. Constant vigilance is maintained in order to prevent stealing diamonds, and yet, notwithstanding this watchfulness, it is estimated that hundreds of thousands of dollars' worth of diamonds are stolen each year. Everything necessary for the sustenance and comfort of the men is brought into the compounds, and no one is permitted to leave until the expiration of his contract except by permission of the overseer, which is seldom given. The men go out of the compounds to their work through tunnels and return the same way. Besides the native Kafirs already mentioned, about two thousand white laborers are employed, the greater number being engaged in the offices and workshops and on the depositing floors. Electric lights are used throughout the mines, and underground work is carried on both day and night by three shifts. Every known scientific device is pressed into service. In all of the deep mines the laborers are taken up and down the shafts in cages. The method of mining and working the diamond-bearing earth at present employed is far more economical than in former years. After the blue material has been brought up it is carried to the depositing floors where it is allowed to remain several months. In the meanwhile it is harrowed several times to break the lumps. The part that resists this treatment is carried to a mill to be crushed. The disintegrated and pulverized material is then carried to the washing machines. The coarser fragments of the concentrates from the washing machines are picked out by hand; the finer are sent to the pulsators. Each shaking-table of the pulsators is made of corrugated iron plates in several sections with a drop of about an inch from one division to another. A sufficient quantity of thick grease is spread over the plates to cover them to the top of the corrugations. The concentrates are continuously spread over the upper portion of the table automatically while running water washes them down.