Possible Clues:

• Sonar's measurement
• Measure sometimes leading to charge for sailors at war?
• Hospital following department's intense quality
• Emotional substance
• What a plumb gauges
• Intensity of short section, hard to follow
• Dumbhead! What? Covering point with profundity?
• What "mark twain" refers to
• That's enough to get the D.P. down
• Heads of departments expect pupils to have intensity