... I left Caen, where I was living, to go on a geologic excursion under the auspices of the School of Mines. The incidents of the travel made me forget my mathematical work. Having reached Coutances, we entered an omnibus to go to some place or other. At the moment when I put my foot on the step, the idea came to me, without anything in my former thoughts seeming to have paved the way for it, that the transformations I had used to define the Fuchsian functions were identical with those of non-Eudidean geometry. I did not verify the idea; I should not have had time, as upon taking my seat in the omnibus, I went on with a conversation already commenced, but I felt a perfect certainty. On my return to Caen, for convenience sake, I verified the result at my leisure.

… the truth is that the knowledge of external nature and of the sciences which that knowledge requires or includes, is not the great or the frequent business of the human mind. Whether we provide for action or conversation, whether we wish to be useful or pleasing, the first requisite is the religious and moral knowledge of right and wrong; the next is an acquaintance with the history of mankind, and with those examples which may be said to embody truth, and prove by events the reasonableness of opinions. Prudence and justice are virtues, and excellencies, of all times and of all places; we are perpetually moralists, but we are geometricians only by chance. Our intercourse with intellectual nature is necessary; our speculations upon matter are voluntary, and at leisure. Physical knowledge is of such rare emergence, that one man may know another half his life without being able to estimate his skill in hydrostatics or astronomy; but his moral and prudential character immediately appears.

’Tis a pity learned virgins ever wed
With persons of no sort of education,
Or gentlemen, who, though well born and bred,
Grow tired of scientific conversation.

[Godfrey H. Hardy] personified the popular idea of the absent-minded professor. But those who formed the idea that he was merely an absent-minded professor would receive a shock in conversation, where he displayed amazing vitality on every subject under the sun. ... He was interested in the game of chess, but was frankly puzzled by something in its nature which seemed to come into conflict with his mathematical principles.

A bacteriologist is a man whose conversation always starts with the germ of an idea.

About eight days ago I discovered that sulfur in burning, far from losing weight, on the contrary, gains it; it is the same with phosphorus; this increase of weight arises from a prodigious quantity of air that is fixed during combustion and combines with the vapors. This discovery, which I have established by experiments, that I regard as decisive, has led me to think that what is observed in the combustion of sulfur and phosphorus may well take place in the case of all substances that gain in weight by combustion and calcination; and I am persuaded that the increase in weight of metallic calxes is due to the same cause... This discovery seems to me one of the most interesting that has been made since Stahl and since it is difficult not to disclose something inadvertently in conversation with friends that could lead to the truth I have thought it necessary to make the present deposit to the Secretary of the Academy to await the time I make my experiments public.

Conversation in society is found to be on a platform so low as to exclude science, the saint, and the poet.

Cuvier had even in his address & manner the character of a superior Man, much general power & eloquence in conversation & great variety of information on scientific as well as popular subjects. I should say of him that he is the most distinguished man of talents I have ever known on the continent: but I doubt if He be entitled to the appellation of a Man of Genius.

Daniel Bernoulli used to tell two little adventures, which he said had given him more pleasure than all the other honours he had received. Travelling with a learned stranger, who, being pleased with his conversation, asked his name; “I am Daniel Bernoulli,” answered he with great modesty; “and I,” said the stranger (who thought he meant to laugh at him) “am Isaac Newton.” Another time, having to dine with the celebrated Koenig, the mathematician, who boasted, with some degree of self-complacency, of a difficult problem he had solved with much trouble, Bernoulli went on doing the honours of his table, and when they went to drink coffee he presented Koenig with a solution of the problem more elegant than his own.

Debate is masculine; conversation is feminine.

DOCTOR. Always preceded by “The good”. Among men, in familiar conversation, “Oh! balls, doctor!” Is a wizard when he enjoys your confidence, a jack-ass when you're no longer on terms. All are materialists: “you can't probe for faith with a scalpel.”

During a conversation with the writer in the last weeks of his life, Sylvester remarked as curious that notwithstanding he had always considered the bent of his mind to be rather analytical than geometrical, he found in nearly every case that the solution of an analytical problem turned upon some quite simple geometrical notion, and that he was never satisfied until he could present the argument in geometrical language.

Edward [Teller] isn’t the cloistered kind of scientist. He gets his ideas in conversation and develops them by trying them out on people. We were coming back from Europe on the Ile de France and I was standing in the ship’s nightclub when he came up and said, 'Freddie, I think I have an idea.’ It was something he’d just thought of about magnetohydrodynamics. I was a bachelor then and I’d located several good-looking girls on the ship, but I knew what I had to do, so I disappeared and started working on the calculations. I’d get something finished and start prowling on the deck again when Edward would turn up out of the night and we’d walk the deck together while he talked and I was the brick wall he was bouncing these things off of. By the end of the trip we had a paper. He’d had the ideas, and I’d done some solving of equations. But he insisted that we sign in alphabetical order, which put my name first.

For the evolution of science by societies the main requisite is the perfect freedom of communication between each member and anyone of the others who may act as a reagent.
The gaseous condition is exemplified in the soiree, where the members rush about confusedly, and the only communication is during a collision, which in some instances may be prolonged by button-holing.
The opposite condition, the crystalline, is shown in the lecture, where the members sit in rows, while science flows in an uninterrupted stream from a source which we take as the origin. This is radiation of science. Conduction takes place along the series of members seated round a dinner table, and fixed there for several hours, with flowers in the middle to prevent any cross currents.
The condition most favourable to life is an intermediate plastic or colloidal condition, where the order of business is (1) Greetings and confused talk; (2) A short communication from one who has something to say and to show; (3) Remarks on the communication addressed to the Chair, introducing matters irrelevant to the communication but interesting to the members; (4) This lets each member see who is interested in his special hobby, and who is likely to help him; and leads to (5) Confused conversation and examination of objects on the table.
I have not indicated how this programme is to be combined with eating.

Grand telegraphic discovery today … Transmitted vocal sounds for the first time ... With some further modification I hope we may be enabled to distinguish … the “timbre” of the sound. Should this be so, conversation viva voce by telegraph will be a fait accompli.

Human societies are glued together with conversation and friendship. Conversation is the natural and characteristic activity of human beings. Friendship is the milieu within which we function.

I asked Fermi whether he was not impressed by the agreement between our calculated numbers and his measured numbers. He replied, “How many arbitrary parameters did you use for your calculations?" I thought for a moment about our cut-off procedures and said, “Four." He said, “I remember my friend Johnny von Neumann used to say, with four parameters I can fit an elephant, and with five I can make him wiggle his trunk.” With that, the conversation was over.

I have often had cause to feel that my hands are cleverer than my head. That is a crude way of characterizing the dialectics of experimentation. When it is going well, it is like a quiet conversation with Nature. One asks a question and gets an answer, then one asks the next question and gets the next answer. An experiment is a device to make Nature speak intelligibly. After that, one only has to listen.

I know each conversation with a psychiatrist in the morning made me want to hang myself because I knew I could not strangle him.

I was introduced to Mr. Davy, who has rooms adjoining mine (in the Royal Institution); he is a very agreeable and intelligent young man, and we have interesting conversation in an evening; the principal failing in his character as a philosopher is that he does not smoke.

If [a man] is sent to a hospital, he is supplied with a topic of conversation, and often is boastful.

In the spring of 1760, [I] went to William and Mary college, where I continued two years. It was my great good fortune, and what probably fixed the destinies of my life, that Dr. William Small of Scotland, was then Professor of Mathematics, a man profound in most of the useful branches of science, with a happy talent of communication, correct and gentlemanly manners, and an enlarged and liberal mind. He, most happily for me, became soon attached to me, and made me his daily companion when not engaged in the school; and from his conversation I got my first views of the expansion of science, and of the system of things in which we are placed.

In the summer of 1937, … I told Banach about an expression Johnny [von Neumann] had once used in conversation with me in Princeton before stating some non-Jewish mathematician’s result, “Die Goim haben den folgendenSatzbewiesen” (The goys have proved the following theorem). Banach, who was pure goy, thought it was one of the funniest sayings he had ever heard. He was enchanted by its implication that if the goys could do it, Johnny and I ought to be able to do it better. Johnny did not invent this joke, but he liked it and we started using it.

It gets you nowhere if the other person’s tail is only just in sight for the second half of the conversation.

Look, first of all, the climate is changing. I don’t think the science is clear what percentage is man-made and what percentage is natural. It’s convoluted. And for the people to say the science is decided on, this is just really arrogant, to be honest with you, it’s this intellectual arrogance that now you can’t have a conversation about it, even. The climate is changing, and we need to adapt to that reality.

Mr. Dalton's aspect and manner were repulsive. There was no gracefulness belonging to him. His voice was harsh and brawling; his gait stiff and awkward; his style of writing and conversation dry and almost crabbed. In person he was tall, bony, and slender. He never could learn to swim: on investigating this circumstance he found that his spec. grav. as a mass was greater than that of water; and he mentioned this in his lectures on natural philosophy in illustration of the capability of different persons for attaining the art of swimming. Independence and simplicity of manner and originality were his best qualities. Though in comparatively humble circumstances he maintained the dignity of the philosophical character. As the first distinct promulgator of the doctrine that the elements of bodies unite in definite proportions to form chemical compounds, he has acquired an undying fame.
Dr John Davy's (brother of Humphry Davy) impressions of Dalton written in c.1830-31 in Malta.

My interest in Science had many roots. Some came from my mother … while I was in my early teens. She fell in love with science,… [from] classes on the Foundations of Physical Science. … I was infected by [her] professor second hand, through hundreds of hours of conversations at my mother’s knees. It was from my mother that I first learned of Archimedes, Leonardo da Vinci, Galileo, Kepler, Newton, and Darwin. We spent hours together collecting single-celled organisms from a local pond and watching them with a microscope.

Next to ignorance of the grammar of one’s native language, nothing betrays want of information so soon as ignorance in matters of geography, without which it is almost impossible to carry on conversation long on any general subject.

Our [scientists] enterprise, the exploration of nature’s secrets, had no beginning and will have no end. Exploration is as natural an activity for human beings as conversation.

People of the same trade seldom meet together, even for merriment and diversion, but the conversation ends in a conspiracy against the public, or in some contrivance to raise prices. It is impossible indeed to prevent such meetings, by any law which either could be executed, or would be consistent with liberty and justice.

Silence is one great art of conversation.

Talking to the Monbuttu was very laborious as the conversation required double interpretation. I spoke in Arabic to a Niam Niam and he spoke in his language to a Niam Niam who understood Monbuttu or to a Monbuttu who understood Niam Niam.

The cell phone has transformed public places into giant phone-a-thons in which callers exist within narcissistic cocoons of private conversations. Like faxes, computer modems and other modern gadgets that have clogged out lives with phony urgency, cell phones represent the 20th Century’s escalation of imaginary need. We didn’t need cell phones until we had them. Clearly, cell phones cause not only a breakdown of courtesy, but the atrophy of basic skills.

The general knowledge of our author [Leonhard Euler] was more extensive than could well be expected, in one who had pursued, with such unremitting ardor, mathematics and astronomy as his favorite studies. He had made a very considerable progress in medical, botanical, and chemical science. What was still more extraordinary, he was an excellent scholar, and possessed in a high degree what is generally called erudition. He had attentively read the most eminent writers of ancient Rome; the civil and literary history of all ages and all nations was familiar to him; and foreigners, who were only acquainted with his works, were astonished to find in the conversation of a man, whose long life seemed solely occupied in mathematical and physical researches and discoveries, such an extensive acquaintance with the most interesting branches of literature. In this respect, no doubt, he was much indebted to an uncommon memory, which seemed to retain every idea that was conveyed to it, either from reading or from meditation.

The most noble and profitable invention of all other, was that of SPEECH, consisting of Names or Appellations, and their Connexion; whereby men register their Thoughts; recall them when they are past; and also declare them one to another for mutuall utility and conversation; without which, there had been amongst men, neither Commonwealth, nor Society, nor Contract, nor Peace, no more than amongst Lyons, Bears, and Wolves.

The United States would be better off if we had less conversation and more conservation.

The vulgar opinion, then, which, on health reasons, condemns vegetable food and so much praises animal food, being so ill-founded, I have always thought it well to oppose myself to it, moved both by experience and by that refined knowledge of natural things which some study and conversation with great men have given me. And perceiving now that such my constancy has been honoured by some learned and wise physicians with their authoritative adhesion (della autorevole sequela), I have thought it my duty publicly to diffuse the reasons of the Pythagorean diet, regarded as useful in medicine, and, at the same time, as full of innocence, of temperance, and of health. And it is none the less accompanied with a certain delicate pleasure, and also with a refined and splendid luxury (non è privo nemmeno d’una certa delicate voluttà e d’un lusso gentile e splendido ancora), if care and skill be applied in selection and proper supply of the best vegetable food, to which the fertility and the natural character of our beautiful country seem to invite us. For my part I have been so much the more induced to take up this subject, because I have persuaded myself that I might be of service to intending diet-reformers, there not being, to my knowledge, any book of which this is the sole subject, and which undertakes exactly to explain the origin and the reasons of it.

There are four classes of Idols which beset men’s minds. To these for distinction’s sake I have assigned names,—calling the first class Idols of the Tribe; the second, Idols of the Cave; the third, Idols of the Market Place; the fourth, Idols of the Theatre …
The Idols of the Tribe have their foundation in human nature itself, and in the tribe or race of men. For it is a false assertion that the sense of man is the measure of things. On the contrary, all perceptions as well of the sense as of the mind are according to the measure of the individual and not according to the measure of the universe. And the human understanding is like a false mirror, which, receiving rays irregularly, distorts and discolours the nature of things by mingling its own nature with it.
The Idols of the Cave are the idols of the individual man. For every one (besides the errors common to human nature in general) has a cave or den of his own, which refracts and discolours the light of nature; owing either to his own proper and peculiar nature; or to his education and conversation with others; or to the reading of books, and the authority of those whom he esteems and admires; or to the differences of impressions, accordingly as they take place in a mind preoccupied and predisposed or in a mind indifferent and settled; or the like.
There are also Idols formed by the intercourse and association of men with each other, which I call Idols of the Market-place, on account of the commerce and consort of men there. For it is by discourse that men associate; and words are imposed according to the apprehension of the vulgar, and therefore the ill and unfit choice of words wonderfully obstructs the understanding. Nor do the definitions or explanations where with in some things learned men are wont to guard and defend themselves, by any means set the matter right. But words plainly force and overrule the understanding, and throw all into confusion, and lead men away into numberless empty controversies and idle fancies.
Lastly, there are Idols which have immigrated into men’s minds from the various dogmas of philosophies, and also from wrong laws of demonstration. These I call Idols of the Theatre; because in my judgment all the received systems are but so many stage-plays, representing worlds of their own creation after an unreal and scenic fashion.

This is the question
Marry
Children—(if it Please God)—Constant companion (& friend in old age) who will feel interested in one—object to be beloved and played with—better than a dog anyhow. Home, & someone to take care of house—Charms of music and female chit-chat.—These things good for one’s health.—but terrible loss of time.—
My God, it is Intolerable to think of spending ones whole life, like a neuter bee, working, working—& nothing after all.—No, no, won’t do. Imagine living all one’s day solitary in smoky dirty London House.—Only picture to yourself a nice soft wife on a sofa with good fire, & books & music perhaps-—Compare this vision with the dingy reality of Grt. Marlbro’ Street.
Not Marry
Freedom to go where one liked—choice of Society and little of it. —Conversation of clever men at clubs—Not forced to visit relatives, & to bend in every trifle. —to have the expense and anxiety of children—perhaps quarreling—Loss of time. —cannot read in the Evenings—fatness & idleness—Anxiety & responsibility—less money for books &c—if many children forced to gain one’s bread. —(but then it is very bad for ones health to work too much)
Perhaps my wife won’t like London; then the sentence is banishment & degradation into indolent, idle fool.
Marry—Marry—Marry Q.E.D.
It being proved necessary to Marry When? Soon or late?

Thomas Godfrey [was] a self-taught mathematician, great in his way…. But he knew little out of his way and was not a pleasing companion, as, like most great mathematicians I have met with, he expected universal precision in everything said, and was forever denying and distinguishing upon trifles, to the disturbance of all conversation.

To Monsieur Lavoisier by appointment. Madame Lavoisier, a lively, sensible, scientific lady, had prepared a dejuné Anglois of tea and coffee, but her conversation on Mr. Kirwan’s Essay on Phlogiston, which she is translating from the English, and on other subjects, which a woman of understanding, that works with her husband in his laboratory, knows how to adorn, was the best repast.

We know enough to be sure that the scientific achievements of the next fifty years will be far greater, more rapid, and more surprising, than those we have already experienced. … Wireless telephones and television, following naturally upon the their present path of development, would enable their owner to connect up to any room similarly equipped and hear and take part in the conversation as well as if he put his head in through the window.

WEATHER, n. The climate of an hour. A permanent topic of conversation among persons whom it does not interest, but who have inherited the tendency to chatter about it from naked arboreal ancestors whom it keenly concerned. The setting up of official weather bureaus and their maintenance in mendacity prove that even governments are accessible to suasion by the rude forefathers of the jungle.

When two minds of a high order, interested in kindred subjects, come together, their conversation is chiefly remarkable for the summariness of its allusions and the rapidity of its transitions. Before one of them is half through a sentence the other knows his meaning and replies. ... His mental lungs breathe more deeply, in an atmosphere more broad and vast...

Whereas what knowledge we derive from lectures, reading and conversation, is but the copy of other men’s men's ideas; that is, the picture of a picture; and ’tis one remove farther from the original.

You can talk about people like Buddha, Jesus, Moses, Confucius, but the thing that convinced me that such people existed were the conversations with Bohr.
About his time working with Niels Bohr in Copenhagen.