ADVERTISEMENT TO THE FOURTH EDITION. 



Thk lajjse of twelve years since the issue of the Third Edition of 

 this work has rendered necessary a Second Supplement, which will be 

 found appended to the present Edition, and will suffice to bring it up 

 to date by indicating what has been done in the interval, with the 

 sources of more detailed information, as well as by stating the more 

 important new facts and making some needed corrections. To facili- 

 tate reference, a General Table of Contents of the Two Supplements 

 has been added. 



No change has been made in the original text of 1868, so that all 



the facts and conclusions stated in the body of the work are of that 



date or earlier. 



J. W. D. 



January 1891. 



