As adults then, in every similar case, are under the necessity of drawing materials from their general knowledge, for the purpose of compounding all such unknown objects, it must be much more difficult for a child to do this, not only because of his want of ability, but his want of materials. The remedy therefore in this case is, to explain and describe the objects that are to be grouped, before the pupil be called upon to do so. And when the object has not been seen by the child, and cannot be exhibited by a picture, or otherwise, the teacher must exert his ingenuity in enabling him to form an idea of the thing that is unknown, by a combination of parts of objects which are. Thus a tiger may be described as resembling a large cat; a wolf, a fox, or even a lion, as resembling certain kinds of dogs; a howdah as a smaller sofa, and a palanquin, as a light crib. In all these cases, it is worthy of notice, that a mere difference of size never creates confusion;--simply because, by a natural law in optics, such differences are of constant occurrence in the experience both of children and adults. A water neut will convey a sufficiently correct idea of a crocodile; and the picture of an elephant, only one inch square, will create no difficulty, if the correct height be given. When these rules have been attended to, it will be found, that this principle in Nature has been successfully imitated; and the pupil, by the previous process of individuation, will be perfectly prepared for the delightful task of grouping the objects which he now knows. When he comes to these objects in the narrative, he conceives the idea of them accurately, and he groups them without effort. There is no hesitation, and no confusion in his ideas. The painting formed upon the mind is correct; the whole picture is united into one connected scene, and is permanently imprinted on the memory for future use. Another circumstance connected with this principle of grouping in children, we found to be, that when, at any time a greater number of objects were presented to the mind than it was able to reiterate and group, it silently dropt the surplus, and grouped those only which came within the reach of its powers; but if in any instance an attempt was made to _force_ the child to receive and reiterate the ideas of objects beyond a certain point, the mind got confused, and its powers weakened.--The imitation of Nature in this point is also of great importance in education, particularly in teaching and exercising children in reading. To perceive this more clearly, it will be necessary to make a few remarks on the nature of the art of reading.