Preface Continued 



are utilized, the context and illustrations will enable the reader readily to comprehend 

 them. All articles have been scrutinized by the editors for the purpose of securing 

 clearness. Every writer has had it impressed upon him that each sentence should 

 be so constructed that the reader will not have to go over any part of it a second time 

 in order to grasp its meaning. 



It was decided when the plans were being prepared for THE WORLD BOOK that it 

 should be abundantly and effectively illustrated. This decision has been carried out 

 fully. Over five thousand pictures appear in these volumes. Topics in any depart- 

 ment which could not well be illustrated by photographs are made clear by diagrams 

 and sketches which show all significant facts of structure, function and relation. 

 Pictures illustrating historical events are given in plenty. Animal and plant life 

 are richly illustrated with photographs and designs showing structure, function, and 

 adaptation to environment. Every geographical topic is made concrete by the use 

 of maps and photographic illustrations of physiographic and political conditions. 

 Ancient and modern architecture is pictured so that the reader can hardly fail to get 

 the essential characteristics of any style, and there are reproductions of renowned 

 works of art. All pictures, maps, reproductions, and illustrations of every kind were 

 made especially for THE WORLD BOOK by artists working in connection with the 

 editors. 



It is essential, of course, that every topic in an encyclopedia should be treated 

 accurately and authoritatively. In order to insure accuracy as well as timeliness in 

 this work, the editors were assisted by a large staff of specialists in every department 

 of learning and achievement. All important articles have been contributed or re- 

 viewed by these authorities. No topic has been allowed to escape careful scrutiny, 

 to the end that no error of fact might be permitted to enter into this work. 



In order to assist the reader, all long articles have been presented under subheads. 

 The chief points in each of these articles can thus be quickly grasped. In many of 

 the articles an outline of points is presented for the guidance of the teacher, the parent 

 and the pupil, and review and original questions are given upon the contents of these 

 articles. Extensive use has been made of cross references and lists of related topics, 

 so that the reader in the study of any subject can quickly turn to all the articles that 

 relate in any way to it. Generous use has been made also of departmental and general 

 indexes which will enable the reader to locate any subject in which he is interested 

 without loss of time or energy. The correct pronunciation of all unusual or difficult 

 terms is given. 



Special mention should be made of the exceptionally valuable services of the editor, 

 Mr. Ellsworth D, Foster. The completion of THE WORLD BOOK would have been 

 impossible without his varied and extensive knowledge, his organizing skill and 

 his devotion. 



M. V. O'SHEA. 



THE UNIVERSITY OF WISCONSIN. 



IV 



