By perfecting ourselves in military science, paradoxical as it may seem, we are therefore assisting in the diffusion of peace, and hastening on the approach of that period when swords shall be beaten into ploughshares and spears into pruning-hooks." APPENDIX.
Since the first edition of this work was published, two important wars have been commenced and terminated--that between the United States and the Republic of Mexico, and that between Russia and the Western Powers of Europe--and another is now being waged between France and Austria, upon the old battle fields of Northern Italy.

In issuing a new edition of these Elements of Military Art and Science, it is deemed proper to refer to these wars, and to apply the principles here discussed to the military operations carried on in Mexico and in the Crimea.

It is proposed to do this in the form of Notes to the several Chapters.

The war in Italy being still undetermined, and the details of the several battles which have already been fought being but imperfectly known, it is obviously improper to attempt to criticize their strategic character or tactical arrangement.
H.W.H.
NEW YORK, _July_, 1859.
NOTE TO CHAPTER II .-- STRATEGY.
In the invasion of Mexico, the United States formed four separate armies, moving on _four distinct lines of operation:_ 1st.

The "Army of the West," under General Kearny, moving from St.Louis on New Mexico and California; 2d.