Produced by D Alexander and the Online Distributed Proofreading Team at https://www.pgdp.net (This file was produced from images generously made available by The Internet Archive/American Libraries.) ROLLO'S PHILOSOPHY. [AIR.] THE ROLLO SERIES IS COMPOSED OF FOURTEEN VOLUMES, VIZ Rollo Learning to Talk. Rollo Learning to Read. Rollo at Work. Rollo at Play. Rollo at School. Rollo's Vacation. Rollo's Experiments. Rollo's Museum. Rollo's Travels. Rollo's Correspondence. Rollo's Philosophy--Water Rollo's Philosophy--Air. Rollo's Philosophy--Fire. Rollo's Philosophy--Sky. A NEW EDITION, REVISED BY THE AUTHOR. BOSTON: PHILLIPS, SAMPSON, AND COMPANY Entered, according to Act of Congress, in the Year 1855, by PHILLIPS, SAMPSON, & CO., In the Clerk's Office of the District Court of the District of Massachusetts. PREFACE. The main design in view, in the discussions which are offered to the juvenile world, under the title of THE ROLLO PHILOSOPHY, relates rather to their effect upon the little reader's habits of thinking, reasoning, and observation, than to the additions they may make to his stock of knowledge. The benefit which the author intends that the reader shall derive from them, is an influence on the cast of his intellectual character, which is receiving its permanent form during the years to which these writings are adapted. The acquisition of knowledge, however, though in this case a secondary, is by no means an unimportant object; and the discussion of the several topics proceeds accordingly, with regularity, upon a certain system of classification. This classification is based upon the more obvious external properties and relations of matter, and less upon those which, though they are more extensive and general in their nature, and, therefore, more suitable, in a strictly-scientific point of view, for the foundations of a system, are less apparent, and require higher powers of generalization and abstraction; and are, therefore, less in accordance with the genius and spirit of the _Rollo_ philosophy. As teachers have, in some cases, done the author the honor to introduce some of the preceding works of this class into their schools, as reading books, &c., considerable reference has been had to this, in the form and manner of the discussion, and questions have been added to facilitate the use of the books in cases where parents or teachers may make the reading of them a regular exercise of instruction. CONTENTS. CHAPTER I. Page. LOST IN THE SNOW, 9 CHAPTER II. FLYING, 19 CHAPTER III. VALVE MAKING, 40 CHAPTER IV. EXPERIMENTS, 51 CHAPTER V. PRESSURE, 64 CHAPTER VI BALLOONING, 79 CHAPTER VII. PHILOSOPHICAL DISCUSSION, 94