The moral advantages likely to result from the general adoption of this mode of teaching useful knowledge are exceedingly cheering, and the only surprise is, that it has been so long overlooked. That the principle, though not directly applied to the purposes of education, was well known, and frequently practised by our forefathers, appears obvious from many of their valuable writings. One beautiful example of its application is familiar to thousands, though not always perceived, in the illustration given of the Lord's prayer towards the close of the Assembly's Larger and Shorter Catechisms. The study of the lessons there drawn from the truths stated or implied in that prayer, will afford a better idea of the value of this mode of teaching, than perhaps any farther explanation we could give, and to these therefore we refer the reader. Before closing these general observations upon the value and necessity of this method of training the young to the practical use of knowledge, there is a circumstance which should not be omitted, as it tends to double all the advantages of the exercise, both to the teacher and the pupil. It will be found in general, especially in morals, that every practical lesson that is drawn from a truth or passage, actually embodies two,--both of which are equally legitimate and connected with the subject. There is always a _negative_ lesson implied, when the _positive_ lesson is expressed; and there is in like manner a _positive_ implied, whenever it is the _negative_ that is expressed. As for example, when the child, from the history of Cain and Abel, draws the negative lesson that he should _not hate_ his brother; the opposite of that lesson is equally binding in the positive form, that he should _love_ his brother. And when, from the history of Job, the positive lesson is drawn that we ought to be patient; the negative of that lesson becomes equally binding, and the child may, by the very same fact, be taught and enjoined not to be fretful, discontented, or impatient, during sickness or trouble. Of this method of multiplying the practical uses of knowledge, we have a most appropriate example in the Assembly's Larger and Shorter Catechisms, where the illustrations given of the decalogue are conducted upon this important principle, and in a similar way. CHAP. VIII. _On the Imitation of Nature in Teaching the Use of Knowledge by means of the Animal or Common Sense._ A large portion of what has been advanced in the foregoing chapter, has reference to the practical application of all kinds of knowledge, whether by the Animal or Moral sense; and we shall here offer a few additional remarks on the teaching of those branches which are more immediately connected with the former.