The materials used by the Painter are principally white lead, linseed oil, spirits of turpentine, “dryers,” and putty. White lead, which forms the basis of almost all the colours used in house painting, is prepared by exposing strips of lead to the action of acid; but the Painter buys it ready made, in the form of small cakes, or lumps. This white lead is used in all the under coats of paint, and generally makes the body of most of the colours which are afterwards applied. Unfortunately, while it is in the half-fluid state, when it is used by Painters, it is very poisonous and unwholesome, and many workmen suffer severely in their health from its use; but it will be found that this is often caused by their own carelessness in working, and by the want of personal cleanliness. The Painter should not only thoroughly wash his hands before every meal, but as soon as his work is done should entirely change his clothes, and wash hands and face thoroughly, or even take a bath. Beside this, he should wear, over his working clothes, a coarse linen frock or blouse, which will protect him from the spots of paint, and may be frequently washed. Linseed oil and spirits of turpentine are used for mixing and thinning the colours; linseed oil is obtained from the seeds of the flax plant, which are heated, beaten, and pressed by machinery, until the greater part of the oil is extracted; the seeds crushed into cakes are then used as food for cattle. Nut oil, or the oil pressed from various kinds of nuts, such as walnuts, hazel and beech nuts, is also frequently used for mixing colours where they are likely to be exposed to the weather, but linseed oil is cheaper and is most generally adapted to the purpose. Oil of turpentine, which the Painter calls “turps,” is the oil obtained by distilling crude turpentine; and is used by the House Painter to make his colours work more smoothly and freely in the brush, to cause them to dry more quickly, and to take away that shiny unpleasant glare that would otherwise be seen on the surface of paint mixed with linseed oil alone. It is necessary, too, to take some means to make the linseed oil dry more rapidly than it would in its raw state; or the paint would remain moist and greasy upon the walls for a very long time. For this purpose the oil is boiled, and is then known as “boiled oil,” this is bought ready prepared, the Painter having by him preparations of lead or vitriol, called “dryers,” which he mixes with his colours, after they are made, in order to increase the rapidity with which they set upon the places where they are applied.