. vi PREFACE. 



to place before him or her such an account of the principal 

 steps in the progress of science as will be intelligible through- 

 out. The whole body and matter of any department of 

 knowledge cannot of course be all passed in review ; but those 

 researches, discoveries, and theories which have contributed 

 to furnish its form and principles may be traced in their incep- 

 tion, progression, and completion. In the following chapters 

 the endeavour has .been to follow the main lines along which 

 each science has developed, by adducing such specific experi- 

 ments, observations, and reasonings as support or illustrate the 

 most important results. The intermixture with the scientific 

 matter of more or less brief biographical notes concerning 

 the great men who have made science, and the introduction of 

 the portraits of many of them, will, it is hoped, import into 

 the present work some of that element of " human interest " 

 in which books of pure science are often accused of being 

 deficient. 



As science is a word with a wide extent of application, it will 

 of course be readily understood that it is used in the title of 

 this work with a limitation of its sense, and this limitation will; 

 best be defined by an enumeration of the branches of science 

 treated of in the present volume. These are: Astronomy; the 

 Physical Sciences light, heat, electricity, etc. ; Chemistry, 

 and the group which we venture to call the Natural History 

 Sciences botany, zoology, geology, etc. ; and, to a certain small 

 extent, Mathematics. As the last is a study popularly sup- 

 posed to offer few attractions, we hasten to add, that it is only 

 because they have proved mighty instruments in advancing 

 the other sciences, that we have given some brief and very 

 simple illustrations of the nature of such inventions as lo- 

 garithms, the Cartesian geometry, and the infinitesimal calculus; 

 but, as it is not to be expected that the general reader will 

 most commonly be a votary of 



" The hard-grain'd Muses of the cube and square," 

 no reference is made to the subsequent development of mathe- 



