“The object most interesting to me for the residue of my life, will be to see you both developing daily those principles of virtue and goodness which will make you valuable to others and happy in yourselves, and acquiring those talents and that degree of science which will guard you at all times against ennui, the most dangerous poison of life. A mind always employed is always happy. This is the true secret, the grand recipe for felicity....In a world which furnishes so many employments which are useful, and so many which are amusing, it is our own fault if we ever know what ennui is...”

“Peace and friendship with all mankind is our wisest policy, and I wish we may be permitted to pursue it.”

“This is the fourth?

“...never [enter] into dispute or argument with another. I never saw an instance of one of two disputants convincing the other by argument. I have seen many, on their getting warm, becoming rude, & shooting one another. ... When I hear another express an opinion which is not mine, I say to myself, he has a right to his opinion, as I to mine; why should I question it? His error does me no injury, and shall I become a Don Quixote, to bring all men by force of argument to one opinion? ... There are two classes of disputants most frequently to be met with among us. The first is of young students, just entered the threshold of science, with a first view of its outlines, not yet filled up with the details & modifications which a further progress would bring to their knoledge. The other consists of the ill-tempered & rude men in society, who have taken up a passion for politics. ... Consider yourself, when with them, as among the patients of Bedlam, needing medical more than moral counsel. Be a listener only, keep within yourself, and endeavor to establish with yourself the habit of silence, especially on politics. In the fevered state of our country, no good can ever result from any attempt to set one of these fiery zealots to rights, either in fact or principle. They are determined as to the facts they will believe, and the opinions on which they will act. Get by them, therefore, as you would by an angry bull; it is not for a man of sense to dispute the road with such an animal.”

“It is reasonable that everyone who asks justice should do justice” 

“I have the consolation of having added nothing to my private fortune during my public service, and of retiring with hands clean as they are empty.”

“I write nothing for publication, and last of all things should it be on the subject of religion. On the dogmas of religion as distinguished from moral principles, all mankind, from the beginning of the world to this day, have been quarrelling, fighting, burning and torturing one another, for abstractions unintelligible to themselves and to all others, and absolutely beyond the comprehension of the human mind. Were I to enter on that arena, I should only add an unit to the number of Bedlamites.

“I shall not die without a hope that light and liberty are on a steady advance. Even should the cloud of barbarism and despotism again obscure the science and liberties of Europe, this country remains to preserve and restore light and liberty to them. In, short, the flames kindled on the 4th of July, 1776, have spread over too much of the globe to be extinguished by the feeble engines of despotism; on the contrary, they will consume these and all who work for them.”

“History, I believe, furnishes no example of a priest-ridden people maintaining a free civil government. This marks the lowest grade of ignorance of which their civil as well as religious leaders will always avail themselves for their own purposes.”

“we commit honest maniacs to Bedlam, so judges should be withdrawn from their bench, whose erroneous biases are leading us to dissolution.”

“The glow of one warm thought is to me worth more than money.”

“You have heard of the new chemical nomenclature endeavored to be introduced by Lavoisier, Fourcroy, &c. Other chemists of this country, of equal note, reject it, and prove in my opinion that it is premature, insufficient and false. These latter are joined by the British chemists; and upon the whole, I think the new nomenclature will be rejected, after doing more harm than good. There are some good publications in it, which must be translated into the ordinary chemical language before they will be useful.”

“He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me.” 

“Thomas Jefferson asked himself “In what country on earth would you rather live ” He first answered “Certainly in my own where are all my friends my relations and the earliest and sweetest affections and recollections of my life.” But he continued “which would be your second choice ” His answer “France.”

“On matters of style, swim with the current, on matters of principle, stand like a rock.”