PEEFACE. 



These papers are now collected at the request of 

 friends and correspondents, who think that they may 

 be useful ; and two new essays are added. Most of 

 the articles were written as occasion called for them 

 within the past sixteen years, and contributed to 

 various periodicals, with little thought of their form- 

 ing a series, and none of ever bringing them together 

 into a volume, although one of them (the third) was 

 once reprinted in a pamphlet form. It is, therefore, 

 inevitable that there should be considerable iteration 

 in the argument, if not in the language. This could 

 not be eliminated except by recasting the whole, 

 which was neither practicable nor really desirable. 

 It is better that they should record, as they do, the 

 writer's freely-expressed thoughts upon the subject 

 at the time ; and to many readers there may be some 

 advantage in going more than once, in different 

 directions, over the same ground. If these essays 

 were to be written now, some things might be differ- 

 ently expressed or qualified, but probably not so as 



