The appearance of the book has been delayed considerably beyond the date originally planned for it. The printing was begun in November last, but was interrupted by my illness, and a resulting stay of considerable length in the West Indies.
I shall esteem it a favor if any who may use this book will notify me of misprints or inaccuracies of any sort which they may remark.
Berlin, August, 1885.
NOTE TO THE SECOND EDITION.
In this edition errors have been corrected in the plates wherever possible, otherwise noted in a list of corrections and additions at the end of the book. My thanks are due to Prof. Lanman and Prof. H. F. Burton of Rochester for corrections furnished.
New York, September, 1886.
NOTE TO THE THIRD EDITION.
The revision of the book for the new impression I owe to Dr. Louis H. Gray, to whom I am glad to express my hearty thanks for his kindness in undertaking and performing this irksome task.
Munich, July, 1901.
