almost inevitably escapes, and a hood and exhaust should be provided, however perfectly the machine is said to act. Much of the white lead is converted into paint on the premises, being ground in oil either in pug mills, Torrance mills, or under edge-runners. A negative pressure must be maintained inside the casing, which must enclose the stones. Here the conditions are precisely those described under the manufacture of paints and colours. In some white lead works conversion into paint is done without the dangerous process of stove drying, either by drying under a vacuum or by mixing the white lead directly with oil. In the process of grinding the oil incorporates itself with the white lead, and the water is forced out, running away in a clear stream. _Chamber Process._--In this method, almost universally used in Germany, and adopted in at least one large white lead works in this country, a chamber arranged with numerous sets of parallel bars on which the thin strips of lead are set saddle-wise takes the place of the stack in the Dutch process. Carbonic acid gas and acetic acid vapour act on and corrode the strips. In a period of from eight to ten weeks the corrosions mostly fall to the ground. Such of the strips as do not fall have to be lifted off the bars, having been previously well saturated with water from a hosepipe, and are dropped on to the floor of the chamber. We are not satisfied that working in the dark, confined chamber by artificial light is less dangerous than working on the stacks. Chamber-made lead undergoes practically the same subsequent processes as have been described. _Precipitation Processes._--These also dispense with stacks and the consequent risks attending work on the blue and white beds, but they substitute another--namely, use of oxide of lead (litharge or the suboxide) as the initial product to be carbonated, with the inevitable danger, in the absence of mechanical contrivances entirely closed in, of shovelling dusty material. In many of these methods, however, mechanical arrangements obviate hand labour or contact with dust in all but the first process.