19·4 per cent. solubility. 19·4 per cent. total lead.] [Illustration: FIG. 6.--RAW LEAD USED. 44·1 per cent. solubility. 45·2 per cent. total lead.] [Illustration: FIG. 7.--ROCKINGHAM (RAW LEAD) USED. 50·9 per cent. solubility. 50·9 per cent. total lead.] Ground-laying, colour-dusting, and aerographing to be done under locally applied exhaust ventilation. Proper receptacles to be provided for cotton-wool used and waste cotton-wool to be burnt. No short-sighted person to be employed to do either glaze or colour blowing, unless wearing suitable glasses, and certificate to this effect to be entered in the Health Register. =Litho-Transfer Making[25].=--Transfers for the decoration of earthenware and china are made in special factories, of which there are seven, employing 257 persons. The patterns are impressed in the ordinary chromo-lithographic fashion, but as the enamel colours, containing high percentages of lead, are dusted either mechanically in the machine, or by hand by means of a pad of cotton-wool, danger from dust is great in the absence of maintenance of a negative pressure inside the dusting machine and an efficient exhaust draught behind the bench where the final dusting with flour, to remove the superfluous colour, is done. In one factory, before a fresh colour was applied to the adhesive pattern on the sheets, the machines had to be cleaned as far as possible of the previous colour used. To do this it was necessary for the attendant to enter a closed chamber at the back of each machine, so as to supply the powder to the hoppers which feed the rollers, or to clean them by means of a brush, sometimes as often as every half-hour. The upward exhaust ventilation applied to the interior of the machine tended to draw the dust created in brushing past the worker’s face, and led to severe incidence of poisoning. The remedy suggested by Pendock[26] was to dispense altogether with the need for entering the chamber, to maintain a slight negative pressure inside the machine by downward exhaust, and to remove the dust by means of a small vacuum cleaning plant.