If in this department then, the teacher is to imitate Nature with effect, there are two preliminary objects of which he ought never to lose sight. The first is, that he studiously select from the numerous subjects which may form the staple of education, those only, or at least chiefly, which are to be most useful, and which may most easily and most frequently be put to use by the pupil;--and the second is, that whatever be the truth or the subject taught, the child should, at the time of learning, be instructed in the methods and the circumstances in which it may be used. To neglect these preliminary points, is really to betray the cause of education, and, besides inflicting a lasting injury on the young, to deceive the public. In our enquiries into Nature's method of applying knowledge, we found, in a former chapter, that she employs two distinct agencies in the work. The one we denominated the Natural, or Common Sense; and the other is the Conscience, or Moral Sense:--the one appearing to regulate our knowledge in so far as it refers to the promotion of our own personal and physical comforts; and the other, in so far as it refers to the rights and the well-being of others, and to our own moral good. The method which she employs in working out these two principles, is, as we before explained, very nearly the same; consisting of the perception of some useful truth,--the deduction of a lesson from that truth,--and the application of that lesson to corresponding circumstances. On that account, our attempts to imitate her operations as exhibited by the one, will, in form, be nearly the same as in the other. We shall here, therefore, attend to the methods by which Nature may be successfully imitated under both agencies, and shall then state a few illustrations and facts which are more peculiarly applicable to each in particular.