PREFACE. xiii 



in groups the surest means to make a deep impression on 

 the reader's mind. 



The Author begs to acknowledge his most grateful 

 obligations to the numerous writers whose names appear 

 in the following pages, and who have enabled him to carry 

 out his scheme as well, he fondly hopes, as his plan admitted. 

 For part of the scientific matter he has incorporated, he is 

 particularly indebted to Pouchet, Comte, H. Spencer, Liebig, 

 De Maistre, Brewster, Whewell, Draper, Ganot, Rodwell, 

 S. Laing, and Jevons ; for some of the historical and philo- 

 sophical appreciations he has enunciated, he owes much 

 inspiration to the brilliant works of G. H. Lewes, Prevost- 

 Paradol, Lecky, and John Morley, who are recognised by all 

 impartial minds, not safe guides only, but, among the dis- 

 tinguished throng of philosophers, as some of the foremost 

 representatives of modern thought. 



