Mediums

These are requisites, and upon the kind used and upon their quality depends, to an extent greater than is generally supposed, the appearance of the finished work. The mediums are, as their other general name of vehicles indicates, the carriers of the paint, the means by which it may be spread. The mediums in general use and which give every satisfaction are of two kinds, a spirit and an oil, the latter being the vehicle proper, the former, the thinning agent to render practicable the spreading of the mixed oil and paint in a coat of any desired depth or thickness. The spirit and the oil are both either of turpentine or of tar, spirit and oil of turpentine being used together, and spirit and oil of tar.

Turpentine

The ordinary turpentine of the house-painter will answer the purpose, but it will be found best to procure rectified spirits of turpentine as sold by the druggist, which is as clear as the proverbial crystal, and as limpid as the purest water. The common turpentine may be used for washing brushes. The oil of turpentine is also known as fat oil. It is viscid, much of the consistency of golden syrup, and has something of the color of clouded amber. This may be purchased for a few cents a small bottle, but it may be prepared from spirits of turpentine by any one, thus: Into a flat saucer pour a little spirits of turpentine, say a tablespoonful, according to the size of the saucer, and over the saucer place a layer of muslin, sufficiently close in texture to prevent dust getting to the turpentine, and yet not so close as to prevent evaporation. The saucer with the muslin drawn tight over it should now be put in a place where evaporation will be free, but not over the fire or stove so as to hasten evaporation, or the heat might dissipate the whole. When the spirituous part of the liquid has passed off there will be found left the oil at the bottom of the saucer.

Fresh spirit may be added, and the process repeated until there is enough oil to pour off.

Tar. The spirit of tar is in two shades, one a rich amber, the other a dark brown, but both are alike in nature. The oil of tar corresponds to it in the same way as the oil of turpentine does to the spirit of turpentine. The spirits of oil of tar are of similar use to the other spirit and oil, and are employed principally by those who object to the vapor of the turpentine as causing headache or affecting the throat. The spirits of turpentine and of tar are extremely volatile, the former being somewhat more so than the latter; and during the working, sufficient may pass off to render the paint somewhat troublesome to deal with. This difficulty is, however, only a slight one, and is easily overcome by the use of a little

Oil Of Lavender

Oil of spike, as it is sometimes called, is a perfectly volatile and fluid oil, but very much less vo'a-tile than either of the above mentioned spirits, and a small quantity is added to the other mediums used when it is desired to keep the work open, to counteract its drying or fattening through loss of spirit.

The mediums should be kept in bottles with closely fitting stoppers, especially the spirits, as otherwise these would quickly become "fat" by evaporation.