Bill Diffley, aged 12, of Lancaster, Penna., for his question:

How did Samuel Clemens Get the name Mark Twain?

Samuel Langhorne Clemens spent much of his boyhood on the banks of the mighty Mississippi. His home town was the river port of Hannibal, Missouri. In the 1840's , the great river teemed with boats of all sorts. The muddy sand banks. then, as now, were tricky to navigate. Special river pilots were needed to steer the boats.

Young Sam watched these men at their work. He saw them let down plumb lines to mark the depth of the water. There were marks on the lines to show each fathom of water below the ship. Mark one, meant that there was only six feet, one fathom of water, below. This boat was in danger of being stuck in the mud.

But mark two ‑ or mark twain as it eras called ‑. was another matter. When a pilot called out these cheerful words the boat was safe. It floated on two fathoms, twelve feet of water. The words mark twain were the all‑clear signal for a river boat. Young Sam loved those words as a boy and later ‑when he himself became a river pilot. They sounded to him like a safe and cheerful name.

Still later, Samuel Clemens became a writer. He wrote of the people who lived on and around the busy Mississippi. And he chose the words Mark Twain for his pen name,