☞ _Either of the above volumes will be sent by mail, postage prepaid, to any part of the United States or Canada, on receipt of the price._ Entered, according to Act of Congress, in the year one thousand eight hundred and fifty-seven, by HARPER & BROTHERS, in the Clerk’s Office of the District Court of the Southern District Court of New York. PREFACE. Children are busy observers of natural objects, and have many questions to ask about them. But their inquisitive observation is commonly repressed, instead of being encouraged and guided. The chief reason for this unnatural course is, that parents and teachers are not in possession of the information which is needed for the guidance of children in the observation of nature. They have not themselves been taught aright, and therefore are not able to teach others. In their own education the observation of nature has been almost entirely excluded; and they are, therefore, unprepared to teach a child in regard to the simplest natural phenomena. Here is a radical error in education. When we put a child into the school-room, to be drilled in spelling, reading, arithmetic, geography, etc., we effectually shut him in from all the varied and interesting objects of nature, which he is so naturally inclined to observe and study. These are very seldom made the subjects of instruction in childhood. And even at the fireside the deficiency is nearly as great as it is in the school-room. A similar defect appears to a great extent through the whole course of education. The study of the wonderful phenomena which are all around us and within us, is, for the most part, neglected, except by the few whose inclinations to it are so strong that they can not be repressed. This defect is well illustrated in a remark which was made by a mother in relation to her own education. When at school she stood at the head of her class, and excelled particularly in mathematics. Her remark was, that she every day regretted that much of the time she had given to the study of mathematics had not been spent in learning what would enable her to answer the continual questions of her children. Even when the natural sciences are taught, the mode of teaching them is generally ineffectual. The knowledge which the mass of pupils in our higher schools gain of Natural Philosophy, Chemistry, Botany, and Physiology, is very deficient. There should be a thorough change in this respect in the whole course of education, beginning in childhood. The natural sciences should be made prominent among the studies even of young children, who, in other words, should be encouraged and guided in that observation of nature to which they are generally so much inclined. In the different departments of natural science there are multitudes of facts or phenomena in which children readily become interested, when they are properly explained.