The paragraph concerning Henry, and his employment on the Pennsylvania, begins the story of a tragedy.  The story has been fully told elsewhere,—­[Mark Twain:  A Biography, by same author.] —­and need only be sketched briefly here.  Henry, a gentle, faithful boy, shared with his brother the enmity of the pilot Brown.  Some two months following the date of the foregoing letter, on a down trip of the Pennsylvania, an unprovoked attack made by Brown upon the boy brought his brother Sam to the rescue.  Brown received a good pummeling at the hands of the future humorist, who, though upheld by the captain, decided to quit the Pennsylvania at New Orleans and to come up the river by another boat.  The Brown episode has no special bearing on the main tragedy, though now in retrospect it seems closely related to it.  Samuel Clemens, coming up the river on the A. T. Lacey, two days behind the Pennsylvania, heard a voice shout as they approached the Greenville, Mississippi, landing: 

     “The Pennsylvania is blown up just below Memphis, at Ship Island! 
     One hundred and fifty lives lost!”

It was a true report.  At six o’clock of a warm, mid-June morning, while loading wood, sixty miles below Memphis, the Pennsylvania’s boilers had exploded with fearful results.  Henry Clemens was among the injured.  He was still alive when his brother reached Memphis on the Lacey, but died a few days later.  Samuel Clemens had idolized the boy, and regarded himself responsible for his death.  The letter that follows shows that he was overwrought by the scenes about him and the strain of watching, yet the anguish of it is none the less real.

To Mrs. Onion Clemens: 

Memphis, Tenn., Friday, June 18th, 1858.  Dear sister Mollie,—­Long before this reaches you, my poor Henry my darling, my pride, my glory, my all, will have finished his blameless career, and the light of my life will have gone out in utter darkness.  (O, God! this is hard to bear.) Hardened, hopeless,—­aye, lost—­lost —­lost and ruined sinner as I am—­I, even I, have humbled myself to the ground and prayed as never man prayed before, that the great God might let this cup pass from me—­that he would strike me to the earth, but spare my brother—­that he would pour out the fulness of his just wrath upon my wicked head, but have mercy, mercy, mercy upon that unoffending boy.  The horrors of three days have swept over me—­they have blasted my youth and left me an old man before my time.  Mollie, there are gray hairs in my head tonight.  For forty-eight hours I labored at the bedside of my poor burned and bruised, but uncomplaining brother, and then the star of my hope went out and left me in the gloom of despair.  Men take me by the hand and congratulate me, and call me “lucky” because I was not on the Pennsylvania when she blew up!  May God forgive them, for they know not what they say.