Physicists From France

"To neglect the opportunity of an innocent pleasure is a loss to ourselves."

"Recherché pleasures cause simple pleasures to lose all their attractions."

"It may sometimes be necessary to yield the right, but how is one to recover it when wanted?"

"The truly wise man is he who loves virtue for its own sake."

"War has been represented as necessary to prevent the too rapid increase of the population, but war mows down the flower of the young men, while it spares the men disgraced by nature. Hence it tends to the degeneration of the species."

"The decadence of the Greeks and Romans... proves the influence of institutions upon customs."

"Taxes are regarded by economists as an evil, but as a necessary evil, since they provide for public expenses. Consequently, economists think that if the government possessed sufficient revenues, in domains for example, the suppression of all taxes would be a desirable measure."

"The laws of war, do they say? As if war were not the destruction of all laws."

"If Christianity were pruned of all which is not Christ, this religion would be the simplest in the world."

"Taxes are a means of influencing production and commerce to give to them a direction which they would not naturally have taken. Such an influence may undoubtedly have disagreeable consequences if the taxes are imposed without discrimination or exclusively for a fiscal purpose, but it is entirely otherwise if wisdom and tact preside at their institution."

"What motives have influenced the writers who have rejected all religious systems? Is it the conviction that the ideas which they oppose are all injurious to society? Have they not rather included in the same proscription religion and the abuse of it?"

"The belief in an all-powerful Being, who loves us and watches over us, gives to the mind great strength to endure misfortune."

"Is heat the result of a vibratory motion of molecules? If... so, quantity of heat is simply quantity of motive power. As long as motive power is employed to produce vibratory movements, the quantity of heat must be unchangeable... but when it passes into movements of sensible extent, the quantity of heat can no longer remain constant."

"It would seem... that heat set free should be attributed to the friction of the molecules of the metal, which change place relatively to each other, that is, the heat is set free just where the moving force is expended. ...We may also cite... the heat produced by the extension of a metallic rod just before it breaks... the greater the elongation before rupture, the more considerable is the elevation of temperature."

"According to the doctrine of the church, God resembles a proposing enigmas, and devouring those who cannot guess them."

"When a hypothesis no longer suffices to explain phenomena, it should be abandoned. This is the case with... caloric as matter, as a subtile fluid. The experimental facts tending to destroy this theory are as follows: (1) The development of heat by percussion or the friction of bodies (experiments of Rumford, friction of wheels on... axles...). Here the elevation of temperature takes place at the same time in the body rubbing and the body rubbed. ...Thus heat is produced by motion. If... [caloric] is matter... matter is created by motion. (2) ...[A]ir compressed by the pumps must rise in temperature above the air outside, and it is expelled at a higher temperature. ...Thus heat has been created by motion."

"Liquuefaction of bodies, solidification of liquids, crystallization—are they not forms of combinations of integrant molecules?"

"God cannot punish man for not believing when he could so easily have enlightened and convinced him."

"[[Light|[L]ight]] is generally regarded as the result of a vibratory movement of the ethereal fluid. Light produces heat, or at least accompanies the radiating heat, and moves with the same velocity as heat. Radiating heat is then a vibratory movement. It would be ridiculous to suppose that it is an emission of matter while the light which accompanies it could be only a movement."

"Could a motion (that of radiating heat) produce matter (caloric)? No, undoubtedly; it can only produce a motion. Heat is then the result of a motion. Then it is plain that it could be produced by the consumption of motive power, and that it could produce this power."

"[W]e have just described the re-establishment of equilibrium in the caloric, its passage from a... heated body to a cooler one."

"Steam navigation... tends to unite the nations of the earth as inhahitants of one country. ...is not this the same as greatly to shorten distances?"

"Nature, in providing us with combustibles on all sides, has given us the power to produce, at all times and in all places, heat and the impelling power which is the result of it. To develop this power, to appropriate it to our uses, is the object of heat-engines."

"Iron and heat are... the supporters, the bases, of the mechanic arts."

"There is almost as great a distance between the first apparatus in which the expansive force of steam was displayed and the existing machine, as between the first raft that man ever made and the modern vessel."

"Savery, Newcomen, Smeaton, the famous Watt, Woolf, Trevithick, and some other English engineers, are the veritable creators of the steam-engine."

"The phenomenon of the production of motion by heat has not been considered from a sufficiently general point of view. We have considered it only in machines... [for which] the phenomenon is... incomplete. It becomes difficult to recognize its principles and study its laws. ...[T]he principle of the production of motion by heat... must be considered independently of any mechanism or... particular agent. It is necessary to establish principles applicable not only to steam-engines but to all imaginable heat-engines, whatever the working substance and whatever the method by which it is operated."

"We shall have [a complete theory] only when the laws of Physics shall be extended enough, generalized enough, to make known beforehand all the effects of heat acting in a determined manner on any body."

"Wherever there exists a difference of temperature... it is possible to have also the production of impelling power. ...All substances in nature can be employed for this purpose, all are susceptible of changes of volume, of successive contractions and dilatations, through the alternation of heat and cold. All are capable of overcoming in their changes of volume certain resistances... A solid... A liquid... An aeriform fluid... If it is enclosed in an expansible space, such as a cylinder provided with a piston, it will produce movements of great extent. Vapors of all substances capable of passing into a gaseous condition, as of , of mercury, of , etc., may fulfil the same office as vapor of water. ...Most of these... have been proposed, many even have been tried, although... without remarkable success."

"Heat can evidently be a cause of motion only by virtue of the changes of volume or of form which it produces in bodies."

"[I]f we should find about us only bodies as hot as our furnaces, how can we condense steam? What should we do with it if once produced?"

"[T]he production of heat alone is not sufficient to give birth to the impelling power: it is necessary that there should also be cold; without it, the heat would be useless."

"Vary the mental and bodily exercises with dancing, horsemanship, swimming, fencing with sword and with sabre, shooting with gun and pistol, skating, the sling, stilts, tennis, bowls; hop on one foot, cross the arms, jump high and far, turn on one foot propped against the wall, exercise in shirt in the evening to get up a perspiration before going to bed; turning, joinery, gardening, reading while walking, declamation, singing, violin, versification, musical composition; eight hours of sleep; a walk on awakening, before and after eating; great sobriety; eat slowly, little, and often; avoid idleness and useless meditation."

"Adopt good habits when I change my method of life."

"Form resolutions in advance in order not to reflect during action. Then obey thyself blindly."

"The promptitude of resolutions most frequently accords with their justice."

"Self-possession without self-sufficiency. Courage without effrontery."

"Make intimate acquaintances only with much circumspection; perfect confidence in those who have been thoroughly tested. Nothing to do with others."

"No useless discourse. All conversation which does not serve to enlighten ourselves or others, to interest the heart or amuse the mind, is hurtful."

"Speak little of what you know, and not at all of what you do not know."

"Employ only expressions of the most perfect propriety."

"Listen attentively to your interlocutor, and so prepare him to listen in the same way to your reply, and predispose him in favor of your arguments."

"Never direct an argument against any one. If you know some particulars against your adversary, you have a right to make him aware of it to keep him under control, but proceed with discretion, and do not wound him before others."

"When discussion degenerates into dispute, be silent; this is not to declare yourself beaten."

"The more nearly an object approaches perfection, the more we notice its slightest defects."

"Hope being the greatest of all blessings, it is necessary, in order to be happy, to sacrifice the present to the future."

"Life is a short enough passage. I am half the journey. I will complete the remainder as I can."

"I rejoice for all the misfortunes which might have happened to me, and which I have escaped."

"I do not know why these two expressions, good sense and common sense, are confounded. There is nothing less common than good sense."

"[W]hen a body has experienced any changes, and when after a certain number of transformations it returns to precisely its original state, that is, to that state considered in respect to density, to temperature, to mode of aggregation—let us suppose, I say, that this body is found to contain the same quantity of heat that it contained at first, or else that the quantities of heat absorbed or set free in these different transformations are exactly compensated. This fact has never been called in question. It was first admitted without reflection, and verified afterwards in many cases by experiments with the . To deny it would be to overthrow the whole theory of heat to which it serves as a basis. For the rest, we may say in passing, the main principles on which the theory of heat rests require the most careful examination. Many experimental facts appear almost inexplicable in the present state of this theory."