“What?  I am to cultivate my mind in the street, on the platform, in the train, and in the crowded street again?” Precisely.  Nothing simpler!  No tools required!  Not even a book.  Nevertheless, the affair is not easy.

When you leave your house, concentrate your mind on a subject (no matter what, to begin with).  You will not have gone ten yards before your mind has skipped away under your very eyes and is larking round the corner with another subject.

Bring it back by the scruff of the neck.  Ere you have reached the station you will have brought it back about forty times.  Do not despair.  Continue.  Keep it up.  You will succeed.  You cannot by any chance fail if you persevere.  It is idle to pretend that your mind is incapable of concentration.  Do you not remember that morning when you received a disquieting letter which demanded a very carefully-worded answer?  How you kept your mind steadily on the subject of the answer, without a second’s intermission, until you reached your office; whereupon you instantly sat down and wrote the answer?  That was a case in which you were roused by circumstances to such a degree of vitality that you were able to dominate your mind like a tyrant.  You would have no trifling.  You insisted that its work should be done, and its work was done.

By the regular practice of concentration (as to which there is no secret—­save the secret of perseverance) you can tyrannise over your mind (which is not the highest part of you) every hour of the day, and in no matter what place.  The exercise is a very convenient one.  If you got into your morning train with a pair of dumb-bells for your muscles or an encyclopaedia in ten volumes for your learning, you would probably excite remark.  But as you walk in the street, or sit in the corner of the compartment behind a pipe, or “strap-hang” on the Subterranean, who is to know that you are engaged in the most important of daily acts?  What asinine boor can laugh at you?

I do not care what you concentrate on, so long as you concentrate.  It is the mere disciplining of the thinking machine that counts.  But still, you may as well kill two birds with one stone, and concentrate on something useful.  I suggest—­it is only a suggestion—­a little chapter of Marcus Aurelius or Epictetus.

Do not, I beg, shy at their names.  For myself, I know nothing more “actual,” more bursting with plain common-sense, applicable to the daily life of plain persons like you and me (who hate airs, pose, and nonsense) than Marcus Aurelius or Epictetus.  Read a chapter—­ and so short they are, the chapters!—­in the evening and concentrate on it the next morning.  You will see.

Yes, my friend, it is useless for you to try to disguise the fact.  I can hear your brain like a telephone at my ear.  You are saying to yourself:  “This fellow was doing pretty well up to his seventh chapter.  He had begun to interest me faintly.  But what he says about thinking in trains, and concentration, and so on, is not for me.  It may be well enough for some folks, but it isn’t in my line.”