n A grinding machine consisting of a cylindrical, horizontal shell containing a number of free steel rods and rotated about its axis at a speed such that each rod is lifted almost to the top of the cylinder before it falls to impact the charge of material being ground. Compare Ball Mill. Roentgen \▐rent-gәn, ▐rәnt-, -jәn, -shәn\ adj [ISV, fr. Wilhelm Röntgen] (1896) (R) The former international unit, now being phased out, of quantity or dose of X-rays or gamma rays, a measure of the ionization induced by these rays, equal to 2.58 × 10−4 coulomb per kilogram (C/kg).
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