The object of the following treatise is to present a full and explicit account of the art of Lithography in its various branches, adapted to the requirements alike of the amateur and professional. In its manner, an endeavour has been made to adopt a style simple enough for the learner and the self-educator; while the matter will, it is hoped, be comprehensive enough to be regarded as a useful compendium and vade-mecum for those who already possess a knowledge of the general principles and ordinary practice of the art.

The plan of the treatise is to give, in the first place, a description of the materials, tools, implements, and machinery; then to show their application. The subject is divided into two chief portions,—those appertaining to the provinces respectively of the Artist and the Printer.

The principal subjects are referred to in independent paragraphs, numbered consecutively. This plan insures facility of reference, avoids repetition, and obviates unnecessary recapitulation.

1. The art of lithography is based upon a chemical principle,—that of the attraction and repulsion of various natural substances, and more especially upon the antagonistic qualities of grease and water, or of those substances which are soluble in water and those soluble in oil.

Every one must have observed that grease will not directly combine with water. On this property depends the whole principle of Lithography, however simple or complex the result may be, from the ordinary circular in black to the highly-finished imitation in colours of water, or oil painting.