An Irish soldier had lost an eye in battle, but was allowed to continue in the service on consenting to have a glass eye in its place. One day, however, he appeared on parade without his artificial eye.
Nolan, said the officer, "you are not properly dressed. Why is your artificial eye not in its place?"
Sure, sir, replied Nolan, "I left it in me box to keep an eye on me kit while I'm on parade."