a very short version of a wonderful joke: (I have heard it milked for 5 minutes)

Admiral Nelson's Red Coat

Nelson and Hardy were on the bridge of HMS victory the morning before engaging the French flotilla.

"Admiral Nelson sir" said Hardy, "Why do you wear a red tunic?"

"Well Hardy, it is because if I were to be wounded, the blood would
not show and the crew would think I were still with them."

Good idea sir, I shall wear my brown trousers."