A Chemistry Professor chalked a formula HNO8 on the blackboard. Then he wheeled about and pointed a finger at the sleepiest member of the class. "Identify that formula," he demanded.
"Er, ah," stalled the unhappy student, "I've got it right on the tip of my tongue, sir."
"In that case," said the professor softly, "you'd better spit it out, my boy. It's nitric acid."
"Er, ah," stalled the unhappy student, "I've got it right on the tip of my tongue, sir."
"In that case," said the professor softly, "you'd better spit it out, my boy. It's nitric acid."