Macmillan's Science Monographs 



' I V HE aim of these volumes is to provide a medium through 

 *- which investigators who have made substantial contributions 

 to the advance of Science in particular directions may bring 

 together their results and conclusions and discuss them in connexion 

 with the related work of others. 



Scientific research of to-day is essentially specialised ; and 

 though investigators may make excursions into various parts of 

 the field of natural knowledge, their names are usually associated 

 most closely with studies of specific areas. Surveys thus carried 

 on are described in papers presented to Scientific Societies during 

 a period which may extend over a number of years ; so that the 

 student or the original researcher who desires to know the 

 position of a subject as represented by the work of a leading 

 authority upon it, has to refer to many volumes of Transactions 

 or Proceedings of possibly different Scientific Societies. Occasionally, 

 in an address or an article in a scientific journal, an investigator 

 gives a sketch of the outstanding points of his studies of a subject; 

 but the limitations of space prevent him from doing justice to 

 himself or his work. 



Macmillan's Science Monographs afford to authorities upon 

 definite aspects of science a means by which an adequate statement 

 of their work may be made available to the scientific world 

 within a volume of reasonable dimensions and at a moderate 

 price. The monographs are not intended to be exhaustive records 

 of all the researches that have been carried out in particular 

 subjects, but the expression of the original work of the individual 

 authors, with such consideration of related contributions by others 

 as is demanded of a scientific publication. Each volume is, 

 therefore, unique ; and the series forms a collection of authoritative 

 works which claims a place in every scientific library and is of 

 prime value both to the student and the original investigator. 



i 



