Dear boy:  I recommended to you, in my last, an innocent piece of art; that of flattering people behind their backs, in presence of those who, to make their own court, much more than for your sake, will not fail to repeat and even amplify the praise to the party concerned.  This is, of all flattery, the most pleasing, and consequently the most effectual.  There are other, and many other, inoffensive arts of this kind, which are necessary in the course of the world, and which he who practices the earliest, will please the most, and rise the soonest.  The spirits and vivacity of youth are apt to neglect them as useless, or reject them as troublesome.  But subsequent knowledge and experience of the world reminds us of their importance, commonly when it is too late.  The principal of these things is the mastery of one’s temper, and that coolness of mind, and serenity of countenance, which hinders us from discovering by words, actions, or even looks, those passions or sentiments by which we are inwardly moved or agitated; and the discovery of which gives cooler and abler people such infinite advantages over us, not only in great business, but in all the most common occurrences of life.  A man who does not possess himself enough to hear disagreeable things without visible marks of anger and change of countenance, or agreeable ones, without sudden bursts of joy and expansion of countenance, is at the mercy of every artful knave or pert coxcomb; the former will provoke or please you by design, to catch unguarded words or looks by which he will easily decipher the secrets of your heart, of which you should keep the key yourself, and trust it with no man living.  The latter will, by his absurdity, and without intending it, produce the same discoveries of which other people will avail themselves.  You will say, possibly, that this coolness must be constitutional, and consequently does not depend upon the will:  and I will allow that constitution has some power over us; but I will maintain, too, that people very often, to excuse themselves, very unjustly accuse their constitutions.  Care and reflection, if properly used, will get the better:  and a man may as surely get a habit of letting his reason prevail over his constitution, as of letting, as most people do, the latter prevail over the former.  If you find yourself subject to sudden starts of passion or madness (for I see no difference between them but in their duration), resolve within yourself, at least, never to speak one word while you feel that emotion within you.  Determine, too, to keep your countenance as unmoved and unembarrassed as possible; which steadiness you may get a habit of, by constant attention.  I should desire nothing better, in any negotiation, than to have to do with one of those men of warm, quick passions; which I would take care to set in motion.  By artful provocations I would extort rash unguarded expressions; and, by hinting at all the several things that I could suspect, infallibly