The turner places the vessel on the clipck, and, with his finger, presses its eRge firm, or fixed to the clay-ring pre viously formed on it, the treader gives motion to the spindle, and the turner, by his tools of very thin steel, varying in breadth for the several vessels, carefully abstracts all the surplus clay left by the thrower, and likewise adds all the ele gance the pattern suggests; and, after this is finished, the treader expertly gives to the spindle a retrograde motion, dur ing which the turner applies the flat sur face of his tool to the vessel, and thereby gives the whole a solidity not previously existing, and also a glossy smoothness, preventive of any inequalities the prior operation might have left. It will be readily conjectured, that this manipula tion affords much opportunity for exer cising taste and genius, and requires con siderable practice, to prevent the articles being fractured and destroyed.
In manufactories, where the lathes have motion from a steam-engine, the lathes are so constructed as to receive increased velocity for those parts of the operation which require it. There is a general spur, or driving-shaft, along the room, nigh the wall, and a drum fixed on it, over each lathe, over which a belt passes. The lathe has a small shaft fixed
parallel to its spindle, with one fixed and two loose pulleys ; from the drum, the belt passes round the fixed pulley, which will give motion to either of those loose that may be geared with it. One of these gives the direct motion to the spindle, and the other, to the crossed belt, gives the retrograde.
Some articles, after being taken off the turner's lathe, are only required to be gradually dried, to be ready for being baked in the biscuit-oven; others require to be ornamental, figured, or hurdled, and are placed where they will not dry quickly.
Many articles of a circular figure, and some hollow-ware, of even oval, are form ed and finished on a mould, placed on the head of a vertical spindle, moved by a winch (not dissimilar to a lapidary's wheel), and a larger of clay (butted, as described under pressing), is laid on the mould, and, by swage and sponge, as the spindle revolves, has the full thick ness and shape, at the same operation, completed. This is much used to fabri cate saucers and plates.