What has been said in relation to Form--that the works of our predecessors, so far as they are recognized as true, are to be considered as an extension of Nature, and therefore proper objects of study--is equally applicable to Composition. But it is not to be understood that this extended Nature (if we may so term it) is in any instance to be imitated as a _whole_, which would be bringing our minds into bondage to another; since, as already shown in the second Discourse, every original work is of necessity impressed with the mind of its author. If it be asked, then, what is the advantage of such study, we shall endeavour to show, that it is not merely, as some have supposed, in enriching the mind with materials, but rather in widening our view of excellence, and, by consequent excitement, expanding our own powers of observation, reflection, and performance. By increasing the power of performance, we mean enlarging our knowledge of the technical process, or the medium through which thought is expressed; a most important species of knowledge, which, if to be otherwise attained, is at least most readily learned from those who have left us the result of their experience. This technical process, which has been well called the language of the Art, includes, of course, all that pertains to Composition, which, as the general medium, also contains most of the elements of this peculiar tongue. From the gradual progress of the various arts of civilization, it would seem that only under the action of some great _social_ law can man arrive at the full developement of his powers. In our Art especially is this true; for the experience of one man must necessarily be limited, particularly if compared with the endless varieties of form and effect which diversify the face of Nature; and the finest of these, too, in their very nature transient, or of rare occurrence, and only known to occur to those who are prepared to seize them in their rapid transit; so that in one short life, and with but one set of senses, the greatest genius can learn but little. The Artist, therefore, must needs owe much to the living, and more to the dead, who are virtually his companions, inasmuch as through their works they still live to our sympathies. Besides, in our great predecessors we may be said to possess a multiplied life, if life be measured by the number of acts,--which, in this case, we may all appropriate to ourselves, as it were by a glance. For the dead in Art may well be likened to the hardy pioneers of our own country, who have successively cleared before us the swamps and forests that would have obstructed our progress, and opened to us lands which the efforts of no individual, however persevering, would enable him to reach. Aphorisms. Sentences Written by Mr. Allston on the Walls of His Studio.