PREFACE. rii 



The history of the nineteenth century has been a 

 very difficult and I fear scarcely a successful task ; 

 for, while those who know anything of the subjects 

 mentioned, will feel that the account is very defective 

 owing to so much being left out, the beginner will 

 probably find it difficult owing to so much being put 

 in. The reproach on both sides would be just, yet it 

 seemed better to give even a few of the leading dis- 

 coveries and theories of our own time than to leave 

 the student with such crude ideas of many branches 

 of science as he must have had if the history had 

 ended with the eighteenth century. 



When treating of such varied subjects, many of 

 them presenting great difficulties both as regards 

 historical and scientific accuracy, I cannot expect to 

 have succeeded equally in all, and must trust to the 

 hope of a future edition to correct such grave errors 

 as will doubtless be pointed out, in spite of the care 

 with which I have endeavoured to verify the state- 

 ments made. 



As the size of the book makes it impossible to 

 give the numerous references which would occur on 

 every page, I have named at the end of each chapter 

 a few of the works consulted in its preparation, choos- 

 ing always in preference those which will be useful to 

 the reader if he cares to refer to them. I had also 

 prepared questions on the work ; but those competent 

 to give an opinion, tell me that teachers in these days 

 prefer to prepare their own lessons. I have there- 

 fore substituted, at p. 439, a chronological table of the 



