I have created a scanned pdf version of Mitchell's Class Method for Cornet, copyright 1920. It is in the public domain and the Project Gutenberg people have kindly placed it in a new section of their e-books site: http://preprints.readingroo.ms/.
This book is a gem. It has great tips from the 1920's for teachers and students, many of which are humorous today or still completely applicable. It has plenty of popular songs, "orchestral studies", American tunes, operatic songs, hymn tunes, and bugle calls, besides scales, rhythm studies, etc.
And did I mention it is free? (15Mbytes, 74 pages)