[Illustration: (From a daguerreotype taken in 1846, just before leaving for the front) LIEUT. MCCLELLAN, HIS FATHER AND HIS BROTHER ARTHUR.] THE MEXICAN WAR DIARY OF GEORGE B. McCLELLAN EDITED BY WILLIAM STARR MYERS, Ph.D., ASSISTANT PROFESSOR OF HISTORY AND POLITICS PRINCETON UNIVERSITY PRINCETON UNIVERSITY PRESS PRINCETON LONDON: HUMPHREY MILFORD OXFORD UNIVERSITY PRESS 1917 Copyright, 1917, by PRINCETON UNIVERSITY PRESS Published April, 1917 [Illustration] PREFACE During the past four or five years I have been preparing a life of General McClellan in which I plan especially to stress the political influences behind the military operations of the first two years of the Civil War. The main source for my study has been the large collection of “McClellan Papers” in the Library of Congress at Washington, most of which hitherto never has been published. In this collection is the manuscript Mexican War diary and by the courteous permission and kind cooperation of General McClellan’s son, Professor George B. McClellan of Princeton University, I have been able to make the following copy. I desire to thank Professor McClellan for other valuable help, including the use of the daguerreotype from which the accompanying frontispiece was made. My thanks also are due Professor Dana C. Munro for his timely advice and valued assistance in the preparation of the manuscript for the press. The map is reproduced from the “Life and Letters of General George Gordon Meade,” with the kind permission of the publishers, Charles Scribner’s Sons. It has seemed to me that this diary should prove to be of special value at the present time, for it throws additional light upon the failure of our time honored “volunteer system” and forecasts its utter futility as an adequate defense in a time of national crisis or danger. WM. STARR MYERS. Princeton, N. J. January 3, 1917. LIST OF ILLUSTRATIONS Lieut. McClellan, His Father and His Brother Arthur From a daguerreotype taken in 1846, just before leaving for the front _Frontispiece_ War Map opp. p. 6 First Page of the Mexican War Diary in an Old Blankbook Facsimile reproduction of McClellan’s manuscript opp. p. 40 Church at Camargo, Seen from the Palace Facsimile reproduction of a sketch by McClellan opp. p. 70 INTRODUCTION George Brinton McClellan was born in Philadelphia, Pa., on December 3, 1826. He died in Orange, N. J., on October 29, 1885. His life covered barely fifty-nine years, his services of national prominence only eighteen months, but during this time he experienced such extremes of good and ill fortune, of success and of failure, as seldom have fallen to the lot of one man.