14. Above all things, impress on your men the enormous power of their rifle. I have heard many stories of men not firing at all because they hoped the enemy would come within _bombing range_. I have also heard of bodies of German troops streaming across the open unfired at because no order was given. I have also heard of machine guns stopping a German advance, whilst infantry who were lying down beside them did not fire a shot. 15. Rifle grenades and bombs both have their proper uses, and in trench fighting it would be difficult to get on without them. The former are also excellent for giving covering fire whilst a post is being rushed; but if the infantryman’s worth be 100, of this 100, 85 per cent. belongs to his rifle and bayonet, 10 per cent. to his rifle grenade, and 5 per cent. at the outside to his bomb. 16. Never miss an opportunity to reorganise your company or platoon, as the case may be, ready for the next emergency. 17. After capturing a trench or work, get your Lewis guns into position without any delay. From a small front they can bring a great fire to bear, and they must be given the best position. Under the protection given by them, the remainder of your command must consolidate. (For consolidation, see note to Scheme 7.) 18. Your duty towards the enemy is your duty towards your neighbour reversed. Think how he could make himself most objectionable to you and act in this manner towards him. 19. Always be certain that you understand your orders, and if you are in doubt never hesitate to ask and make certain, even should your commanding officer have a short temper. 20. If you are detached for any specific purpose you should always rejoin your unit when you have accomplished what you were told to do. 21. Do not fail to give negative information. Young officers are very apt to neglect this. It may be of great importance to a commanding officer to know that a certain place is not held by the enemy, and this is just the kind of information that his patrol leaders are apt to forget to send him. 22. Always insist on any verbal order you may give being repeated to you by the recipient before he leaves your presence. 23. In a retirement you send men to the rear with orders to take up another position to protect your retirement; always see that they are accompanied by a competent leader, or when the last party falls back they will very likely find that their retirement is unsupported. Try to remember these axioms. My subsequent letters will be founded on their application. Your affectionate father, “X. Y. Z.” LETTER II [Illustration: W X Y are Pill Boxes W & Y have been captured by us X still holds out ] _December 7, 1917._ MY DEAR DICK,-- I will now proceed to set you a few problems in illustration of the axioms which I gave you at the end of my last letter.