=Must= signifies to be confined, limited, bound, or restrained.  I must, or am bound, to obey; certain obligations require me to obey.  The adjective of this word is in common use.  The air in the cask is musty.  It has long been bound or confined there, and prevented from partaking of the purifying qualities of the atmosphere, and hence has become musty.

=Can.= This word is found as a principal verb and as a noun in our language, especially in the Scotch dialect.  “I ken nae where he’d gone.”  Beyond the ken of mortals.  Far from all human ken.  It signifies to know, to perceive, to understand.  I knew not where he had gone.  Beyond the knowledge of mortals.  Far from all human reach.  To con or cun is a different spelling of the same word. Cunning is that quick perception of things, which enables a person to use his knowledge adroitly.  The child can read; knows how to read.  It can walk.  Here it seems to imply power; but power, in this case, as in most others, is gained only by knowledge, for =knowledge is power=.  Many children have strength sufficient to walk, long before they do.  The reason why they can not walk, is, they do not know how; they have not learned to balance themselves in an erect position, so as to move forward without falling.

A vast proportion of human ability is derived from knowledge.  There is not a being in creation so entirely incapable of self-support, as the new-born infant; and yet, by the help of knowledge, he becomes the lord of this lower world.  Bonaparte was once as helpless as any other child, and yet by dint of can, ken, cunning, or knowledge, he made all Europe tremble.  But his knowledge was limited.  He became blind to danger, bewildered by success, and he could no longer follow the prudent course of wisdom, but fell a sacrifice to his own unbridled ambition, and blinded folly.  An enlightened people can govern themselves; but power of government is gained by a knowledge of the principles of equality, and mutual help and dependency; and whenever the people become ignorant of that fact, they will fall, the degraded victims of their own folly, and the wily influence of some more knowing aspirant for power.

This is a most important topic; but I dare not pursue it farther, lest I weary your patience.  A few examples must suffice.

“Jason, she cried, for aught I see or can,
This deed,” &c.
Chaucer.

                          A famous man,
    Of every witte somewhat he can,
    Out take that him lacketh rule,
    His own estate to guide and rule.
                              Gower.

=Do= has been called a helping verb; but it needs little observation to discover that it is no more so than a hundred other words. “Do thy diligence to come before winter.” “Do the work of an evangelist.”—­Paul to Timothy. I do all in my power to expose the error and wickedness of false teaching. Do afford relief. Do something to afford relief.