I received, by Mr. Mazzei, your letter of April the 20th.  I am much mortified to hear that you have lost so much time; and that when you arrived in Williamsburg, you were not at all advanced from what you were when you left Monticello.  Time now begins to be precious to you.  Every day you lose, will retard a day your entrance on that public stage whereon you may begin to be useful to yourself.  However, the way to repair the loss is to improve the future time.  I trust, that with your dispositions, even the acquisition of science is a pleasing employment.  I can assure you, that the possession of it is, what (next to an honest heart) will above all things render you dear to your friends, and give you fame and promotion in your own country.  When your mind shall be well improved with science, nothing will be necessary to place you in the highest points of view, but to pursue the interests of your country, the interests of your friends and your own interests also, with the purest integrity, the most chaste honor.  The defect of these virtues can never be made up by all the other acquirements of body and mind.  Make these then your first object.  Give up money, give up fame, give up science, give the earth itself and all it contains, rather than do an immoral act.  And never suppose, that in any possible situation, or under any circumstances, it is best for you to do a dishonorable thing, however slightly so it may appear to you.  Whenever you are to do a thing, though it can never be known but to yourself, ask yourself how you would act were all the world looking at you, and act accordingly.  Encourage all your virtuous dispositions, and exercise them whenever an opportunity arises; being assured that they will gain strength by exercise, as a limb of the body does, and that exercise will make them habitual.  From the practice of the purest virtue, you may be assured you will derive the most sublime comforts in every moment of life, and in the moment of death.  If ever you find yourself environed with difficulties and perplexing circumstances, out of which you are at a loss how to extricate yourself, do what is right, and be assured that that will extricate you the best out of the worst situations.  Though you cannot see, when you take one step, what will be the next, yet follow truth, justice, and plain dealing, and never fear their leading you out of the labyrinth, in the easiest manner possible.  The knot which you thought a Gordian one, will untie itself before you.  Nothing is so mistaken as the supposition, that a person is to extricate himself from a difficulty by intrigue, by chicanery, by dissimulation, by trimming, by an untruth, by an injustice.  This increases the difficulties ten fold; and those who pursue these methods, get themselves so involved at length, that they can turn no way but their infamy becomes more exposed.  It is of great importance to set a resolution, not to be shaken, never to tell an untruth.  There is no vice so mean, so pitiful, so contemptible; and he who permits himself to tell a lie once, finds it much easier to do it a second and third time, till a length it becomes habitual; he tells lies without attending to it, and truths without the world’s believing him.  This falsehood of the tongue leads to that of the heart, and in time depraves all its good dispositions.