The Brimsdown process[21], for instance, is automatic and free from dust, except in the initial stage of preparation of litharge in cupellation furnaces. The great risk from the disintegration of this material (see p. 250) by turning it out on the floors is obviated by allowing disintegration to take place in the pots (which must not, therefore, be completely filled), and tipping these when cooled directly into a breaker under powerful exhaust draught. From the bin into which it falls the material is conveyed by dust-proof elevators to (_a_) screens and packing arrangements when the object is flaked litharge, or (_b_), in the case of the bulk of the material for manufacture of white lead, by enclosed conveyors to reducers and mixing mills, where reduction and hydration take place. It is then charged automatically into weak solution of acetic acid, and by agitation with carbonic acid gas converted into basic carbonate of lead. From the carbonators pumps force it into filter presses, where the acetate is drained off and washed out by pure water. The cakes of white lead are fed into mixing machines and pugged with linseed-oil until the water has been entirely removed, and finally passed through the roller mills to be packed in casks. Dry white lead is made by feeding a metal travelling lattice with pulp white lead inside a drying chamber entirely closed in. When dry, the white lead is automatically brushed off, elevated, and automatically packed in a chamber under efficient exhaust draught. In this part of the process, therefore, risk to the workers is very small. The stringent Special Rules for the White Lead Industry show what other precautions, in addition to exhaust ventilation, are necessary--especially personal cleanliness. The effect of one other factor--casual labour--however, must be referred to. The condition at the present time is very different from that which existed twelve years ago. From one factory in 1899, depending much on casual labour, 111 cases were reported, and from another 72. In an inquiry made by one of us in 1898, information was obtained of the actual number employed on any one date, and of the total number passing through the factories in a year. Among the firms with regular employment at that time, the incidence of lead poisoning was 60 per 1,000 on the average number employed, and in those with casual employment 390 per 1,000. Work in lead had secured a bad name, and no one who could get employment elsewhere would take to it. Consequently, the class of men applying for work was a low one--men discharged from other employment and those unfitted for skilled labour. Not a few were addicted to alcohol. The work was unskilled, and had the additional advantage to men of that class that much of it was piece work, paid at a good rate, which could be finished as a rule by three o’clock in the afternoon.