The purport of such works is the conversion of pig-lead into white- lead. This conversion is brought about by the slow and gradual effecting of certain successive chemical changes in the lead itself. The processes are picturesque and interesting,--the most so, being the burying of the lead, at a certain stage of preparation, in pots, each pot containing a certain quantity of acid besides, and all the pots being buried in vast numbers, in layers, under tan, for some ten weeks.
Hopping up ladders, and across planks, and on elevated perches, until I was uncertain whether to liken myself to a bird or a brick- layer, I became conscious of standing on nothing particular, looking down into one of a series of large cocklofts, with the outer day peeping in through the chinks in the tiled roof above. A number of women were ascending to, and descending from, this cockloft, each carrying on the upward journey a pot of prepared lead and acid, for deposition under the smoking tan. When one layer of pots was completely filled, it was carefully covered in with planks, and those were carefully covered with tan again, and then another layer of pots was begun above; sufficient means of ventilation being preserved through wooden tubes. Going down into the cockloft then filling, I found the heat of the tan to be surprisingly great, and also the odour of the lead and acid to be not absolutely exquisite, though I believe not noxious at that stage. In other cocklofts, where the pots were being exhumed, the heat of the steaming tan was much greater, and the smell was penetrating and peculiar. There were cocklofts in all stages; full and empty, half filled and half emptied; strong, active women were clambering about them busily; and the whole thing had rather the air of the upper part of the house of some immensely rich old Turk, whose faithful seraglio were hiding his money because the sultan or the pasha was coming.
As is the case with most pulps or pigments, so in the instance of this white-lead, processes of stirring, separating, washing, grinding, rolling, and pressing succeed. Some of these are unquestionably inimical to health, the danger arising from inhalation of particles of lead, or from contact between the lead and the touch, or both. Against these dangers, I found good respirators provided (simply made of flannel and muslin, so as to be inexpensively renewed, and in some instances washed with scented soap), and gauntlet gloves, and loose gowns. Everywhere, there was as much fresh air as windows, well placed and opened, could possibly admit. And it was explained that the precaution of frequently changing the women employed in the worst parts of the work (a precaution originating in their own experience or apprehension of its ill effects) was found salutary. They had a mysterious and singular appearance, with the mouth and nose covered, and the loose gown on, and yet bore out the simile of the old Turk and the seraglio all the better for the disguise.
At last this vexed white-lead, having been buried and resuscitated, and heated and cooled and stirred, and separated and washed and ground, and rolled and pressed, is subjected to the action of intense fiery heat. A row of women, dressed as above described, stood, let us say, in a large stone bakehouse, passing on the baking-dishes as they were given out by the cooks, from hand to hand, into the ovens.