Read "Some Principles of Frontier Mountain Warfare" by Wilkinson Dent Bird online for free on Textopian. Full text with search, annotations, highlights, and AI-powered reading aids.
A body of troops moving in an enemy's country is liable to be attacked at any time, and from any direction, and must, therefore, always take measures for the protection of its front, flanks, and rear.
In warfare in civilised and highly developed countries, when the enemy's object is rather to defeat the fighting force than to harry the convoy, and when troops can march on broad frontages, the protection given by bodies of cavalry with horse artillery, flung far to front and flanks, and supported, if necessary, by infantry, is usually adequate.