| | |after each coat). | |Burning off old paint | 6·50|White paint of London and North-| | | |Western coach. Gas-burner used. | +-----------------------------+-----+--------------------------------+ =Dust.=--Reference to the table shows that the conditions in the pottery workrooms, as stated in Column 7, are reflected in Columns 3 and 5. Further details from his experiments may be useful. Thus, in a dipping room where low-solubility glaze was in use, the amount of lead in the dust collected per 10 cubic metres of air was 0·70 milligramme. The average of four experiments where there were no dipping boards was 1·80 milligrammes, and where dipping boards were used, 3·75; _i.e._, 1·95 milligrammes of lead in the dust per 10 cubic metres of air is added by the use of dirty dipping boards. As the result of his experiments, Duckering believes that approximately 1·95 milligrammes of lead per 10 cubic metres of air was due to the fine spray given off in the shaking of the ware. In bright sunlight, he says, the spray can be seen dancing high above the dipping tub. In a dipping house where work was done slowly by two occupants only, the proportion of lead in the measured quantity of air was also low--0·58 milligramme per 10 cubic metres. Where, in the absence of special provision made for admission of fresh air to a fan, the air was drawn from a neighbouring room in which lead processes were carried on, the amount of lead rose to 5·76 milligrammes at the level breathed by the gatherer at a mangle. In ware-cleaning the average of all his observations where lead was used (eleven) was 3·44 milligrammes; and he concluded that “wet cleaning of ware causes less direct contamination of the atmosphere, even where no local exhaust is applied. A still more important result of wet cleaning, however, is that the overalls keep much freer of dust.” The highest results were obtained when the process of ware-cleaning was done outside the influence of the exhaust draught. In one instance, where the ware was cleaned at a distance of 6 feet from the exhaust opening, 13·34 milligrammes per 10 cubic metres of air were found. Subsequently at the same point, after the exhaust system of ventilation had been remodelled, 0·95 milligramme only was present. Even in a stillage room in which no work was done other than the placing on and removal of the boards from the racks, the lead content per 10 cubic metres of the air was 1·08 milligrammes. In glost-placing, the average of four experiments was 1·83 milligrammes--no doubt the result of glaze on the boards. As much as 9·11 milligrammes of lead was found per 10 cubic metres of air in the centre of a large majolica-painting room, with wooden floors and much traffic in it. Wooden floors generally appeared to influence the results, as determinations of the lead present were higher in rooms with them than with tiled floors.