It was not all smooth sailing, however.  In the course of time I began to realize that these marvelous dictated chapters were not altogether history, but were often partly, or even entirely, imaginary.  The creator of Tom Sawyer and Huck Finn had been embroidering old incidents or inventing new ones too long to stick to history now, to be able to separate the romance in his mind from the reality of the past.  Also, his memory of personal events had become inaccurate.  He realized this, and once said, in his whimsical, gentle way: 

   “When I was younger I could remember anything, whether it happened
   or not; but I am getting old, and soon I shall remember only the
   latter.”

Yet it was his constant purpose to stick to fact, and especially did he make no effort to put himself in a good light.  Indeed, if you wanted to know the worst of Mark Twain you had only to ask him for it.  He would give it to the last syllable, and he would improve upon it and pile up his sins, and sometimes the sins of others, without stint.  Certainly the dictations were precious, for they revealed character as nothing else could; but as material for history they often failed to stand the test of the documents in the next room—­the letters, notebooks, agreements, and the like—­from which I was gradually rebuilding the structure of the years.

In the talks that we usually had when the dictations were ended and the stenographer had gone I got much that was of great value.  It was then that I usually made those inquiries which we had planned in the beginning, and his answers, coming quickly and without reflection, gave imagination less play.  Sometimes he would touch some point of special interest and walk up and down, philosophizing, or commenting upon things in general, in a manner not always complimentary to humanity and its progress.

I seldom asked him a question during the dictation—­or interrupted in any way, though he had asked me to stop him when I found him repeating or contradicting himself, or misstating some fact known to me.  At first I lacked the courage to point out a mistake at the moment, and cautiously mentioned the matter when he had finished.  Then he would be likely to say: 

   “Why didn’t you stop me?  Why did you let me go on making a donkey
   of myself when you could have saved me?”

So then I used to take the risk of getting struck by lightning, and nearly always stopped him in time.  But if it happened that I upset his thought, the thunderbolt was apt to fly.  He would say: 

   “Now you’ve knocked everything out of my head.”

Then, of course, I was sorry and apologized, and in a moment the sky was clear again.  There was generally a humorous complexion to the dictations, whatever the subject.  Humor was his natural breath of life, and rarely absent.

Perhaps I should have said sooner that he smoked continuously during the dictations.  His cigars were of that delicious fragrance which belongs to domestic tobacco.  They were strong and inexpensive, and it was only his early training that made him prefer them.  Admiring friends used to send him costly, imported cigars, but he rarely touched them, and they were smoked by visitors.  He often smoked a pipe, and preferred it to be old and violent.  Once when he had bought a new, expensive briar-root, he handed it to me, saying: