Deists

"[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."

"Plan in the morning the work of the day, and reflect in the evening on what has been done."

"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."

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

"Love is almost the only passion that the good man may avow. It is the only one which accords with delicacy."

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

"We say that man is an egotist, and nevertheless his sweetest pleasures come to him through others. He only tastes them on condition of sharing them."

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

"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."

"According to the system of modern economists, it would be desirable that the government should interfere as little as possible in the commerce and industry of the country. Nevertheless we cannot deny that in certain circumstances this intervention is very useful."

"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."

"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."

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

"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."

"Suffer slight disagreeables without seeming to perceive them, but repulse decisively any one who evidently intends to injure or humiliate you."

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

"Question thyself to learn what will please others."

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

"Speak to every one of that which he knows best. This will put him at his ease, and be profitable to you."

"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."

"Show neither passion nor weariness in discussion."

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

"How much modesty adds to merit! A man of talent who conceals his knowledge is like a branch bending under a weight of fruit."

"Egotism is the most common and most hated of all vices. Properly speaking, it is the only one which should be hated."

"The pleasures of self-love are the only ones that can really be turned into ridicule."

"The strain of suffering causes the mind to decay."

"It must be that all honest people are in the galleys; only knaves are to be met with elsewhere."

"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?"

"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."

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

"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?"

"[C]hanges caused in the temperature of bodies by motion have been very little studied. This class of phenomena merits... attention... When bodies are in motion, especially when that motion disappears, or when it produces motive power, remarkable changes take place in the distribution of heat, and perhaps in its quantity."

"The Collision of Bodies. ...[I]n the collision of bodies there is always expenditure of motive power. Perfectly elastic bodies only form an exception, and none such are found in nature."

"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."

"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."

"To take away to-day from England her steam-engines would be to take away at the same time her coal and iron. It would be to dry up all her sources of wealth, to ruin all on which her prosperity depends, in short, to annihilate that colossal power."

"Notwithstanding the work of all kinds done by steam-engines... their theory is very little understood, and the attempts to improve them are still directed almost by chance."

"[T]here cannot be loss of living force, or, which is the same thing, of motive power, if the bodies act upon each other without directly touching each other, without actual collision. ...[T]he molecules of bodies are always separated from each other by some space ...they are never actually in contact. If they touched each other, they would remain united, and consequently change form. If the molecules of bodies are never in close contact with each other, whatever... forces... separate or attract them, there can never be either production or loss of motive power... This power must be as unchangeable in quantity as matter."

"Heat is simply motive power, or rather motion which has changed form. It is a movement among the particles of bodies. Wherever there is destruction of motive power there is, at the same time, production of heat in quantity exactly proportional to the quantity of motive power destroyed. Reciprocally, wherever there is destruction of heat, there is production of motive power."

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

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

"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."

"Carnot considered that the steam engine was analogous to another prime mover, the water wheel. The analogy, and the upon which it was based, led Carnot to the incorrect conclusion that no heat was lost, or converted into mechanical energy during the operation of the steam engine. He thought that the same quantity of heat was given out by the boiler at the higher temperature as was received by the condenser at the lower temperature. However, the analogy led him also to the fruitful conception that the amount of energy produced... was solely dependent, in principle, upon the temperature difference between the boiler and the condenser and the amount of heat which passed from the one to the other. Thus it appeared that all heat engines in general, would have the same efficiency if they worked within the same temperature levels. He substantiated this... Carnot's principle, by pointing out that would be possible if it were not true. If two perfect heat engines operating between the same temperature levels did not have the same efficiency, it would be possible for the more efficient... to drive the less efficient engine backwards, pumping heat from the lower to the higher temperature, thus leaving the thermal conditions unchanged and yet generating a continuous excess of energy."

"The production of motive power is then due... not to an actual consumption of caloric, but to its transportation from a warm body to a cold body... to its re-establishment of equilibrium..."

"The maximum of motive power resulting from the employment of steam is also the maximum of motive power realizable by any means whatever.1878"

"The production of motion in steam-engines is always accompanied by... the re-establishing of equilibrium in the caloric; that is, its passage from a body in which the temperature is more or less elevated, to another in which it is lower."

"What happens... in a steam-engine... ? The caloric developed in the furnace by the effect of the combustion traverses the walls of the boiler, produces steam, and in some way incorporates itself with it. The latter carrying it away, takes it first into the cylinder, where it performs some function, and from thence into the condenser, where it is liquefied by contact with the cold water... [T]he cold water of the condenser takes possession of the caloric... It is heated by the intervention of the steam as if it had been placed directly over the furnace. The steam is here only a means of transporting the caloric."

"[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."

"The whole theory rests on a principle generally admitted as an axiom, which Carnot expresses in the following terms:— "In our demonstration, we tacitly assume that after a body has experienced a certain number of transformations, if it be brought identically to its primitive physical state as to density, temperature, and molecular constitution, it must contain the same quantity of heat as that which it initially possessed; or, in other words, we suppose that the quantities of heat lost by the body under one set of operations, are precisely compensated by those which are absorbed in the others. This fact has never been doubted; it has at first been admitted without reflection, and afterwards verified in many cases by calorimetrical experiments. To deny it would be to overturn the whole theory of heat, of which it is a fundamental principle. It must be admitted, however, that the chief foundations on which the theory of heat rests would require a most attentive examination. Several experimental facts appear nearly inexplicable in the actual state of this theory." Since the time when Carnot thus expressed himself, the necessity of a most careful examination of the entire experimental basis of the theory of heat has become more and more urgent. Especially all those assumptions depending on the idea that heat is a substance invariable in quantity, not convertible into any other element, and incapable of being generated by any physical agency..."