The principle of Grouping, or Association, as employed by Nature in her educational process, is obviously intended to enable the pupil easily to receive knowledge, and to assist the memory in retaining and keeping it ever after at the command of the will. It is employed to unite many objects or truths into one aggregate mass, which is received as one,--having the component parts so linked, or associated together, that when any one part is afterwards brought before the mind, it has the power of immediately conjuring up, and holding in review, all the others. For example, when a child enters a room in which its parents and relations are severally employed, the whole scene is at a single glance comprehended and understood, and will afterwards be distinctly remembered in all its parts. The elements of the scene are no doubt all familiar, but the particular grouping of these elements are _entirely new_, and form an addition to his knowledge, as we formerly explained, as substantial, and as distinct, as the grouping of any other kind of objects or circumstances could possibly do. Here then is a certain amount of knowledge acquired by the child, which could be recorded in writing, or which might be communicated by words; but which, by the operation of this principle of grouping, has been acquired with greater ease, and in much less time, than he could either have read it, or described it. It has been done in this instance by Nature bringing the _ideas_ suggested by the group directly before the mind of the child, without even the intervention of words; and we see by this example, how much more laborious it would have been to communicate the very same amount of knowledge to the pupil, by making him _read_ the description of it, and how utterly preposterous and unnatural it would be to compel him, for the same purpose, to commit the words of that description to memory. The words are merely an artificial contrivance for the conveying of ideas;--and the more they can be kept out of view, it will be better for the teacher, and more natural and easy for the child. In communicating knowledge, therefore, to the young, the more directly and simply the ideas to be communicated are presented to the mind the better. They must usually be communicated by words; but these, as the mere instruments of conveyance, should be kept as much as possible out of view. To bring them at all under the notice of the child is a defect; but to make them the chief object of learning, or to make the pupil commit them to memory, is not only laborious and unnecessary, but is unnatural and hurtful.