Ideal gas

“ It succeeded perfectly, but, of course, either the expense of the gas, the faint light of its flame, or its poisonous qualities, would preclude its application. But we may, perhaps, without being considered extravagant, be allowed to search in the products of oil, resins, coal, &c., distilled, or otherwise treated, with this object in view, for a substance, which being a gas at common temperatures and pressure, shall condense into a liquid, by a pressure of from two to six or eight atmospheres, and which being combustible, shall afford a lamp of the kind described [8] . ”

“ It is clear that were any texture known which would permit a heat-impulse to pass through it in one direction only, nothing more would be necessary than to place a portion of gas in such a receptacle of this substance, so faced as to permit egress but not entrance of the heat, and the gas thus enclosed, were it hydrogen itself, would very soon become liquid and solid, through spontaneous giving off of its energy, without any manipulation whatever. ”

“ Now we know that to burn a given quantity of gas we must supply it with a sufficient quantity of oxygen, i.e., of the active principle of the air; but this is not all: we all know well enough that if cold coal-gas and cold air be brought together in any proportion whatever no combustion occurs. A certain amount of heat is necessary to start the chemical combination of oxygen with hydrogen and carbon, which combination is the combustion, or burning. ”

“ But now suppose our portion of gas, instead of being placed under our hypothetical building, is plunged into a cold medium, which will permit its heat-vibrations to exhaust themselves without being correspondingly restored. Then, presently, the temperature is lowered below the critical point, and, presto! the mad struggle ceases, the atoms lie amicably together, and the gas has become a liquid. What a transformed thing it is now. Instead of pressing out with that enormous force, it has voluntarily contracted as the five thousand tons pressure could not make it do ”

“ The inflammable gas, which lights our streets, churches, shops, &c., is procured chiefly from coal, burnt in furnaces for the purpose the gas being passed through metal pipes, conveyed underground to the places where the light is required: escaping at the orifice prepared for it, it is lighted when wanted, and burns with, a brilliant flame. This gas consists of hydrogen and carbon; and the oxygen of the air, combined with the hydrogen, causes light as long as hydrogen and oxygen exist and combine. ”

“ But let us go a step further: why must the solid sulphur be converted into a gas? We want a flame, and whenever we have flame it is absolutely necessary that we should have a gas to burn. You cannot have flame without you have gas. Let me endeavour to illustrate what I mean. I pour into this flask a small quantity of ether, a liquid easily converted into a gas. If I apply a lighted taper to the mouth of the flask, no gas, or practically none, being evolved at the moment, nothing happens. But I will heat the ether so as to convert it into a gas. ”

“ As the proportion of light given out by the flame of a gaseous compound of carbon and hydrogen, is in common circumstances in proportion to the quantity of carbon present; it is evident that the gas which contains a greater proportion of olifiant gas, or supercarburetted hydrogen than coal gas, will yield a better and brighter light on combustion. ”

“ Recollect that the gas from one of the wires was hydrogen, the one-ninth of water. What should you guess the gas from the other wire to be?”
“Stop—eh?—wait a bit—eh—oh!—why, the other eight-ninths, to be sure.”
“Good again, uncle. Now this gas that is eight-ninths of water is the gas called oxygen that I mentioned just now. This is a very curious gas. It won’t burn in air at all itself, like gas from a lamp, but it has a wonderful power of making things burn that are lighted and put into it. ”

“ Ellisen, of the Paris gas-works, have shown that the gases rich in carbon, such as defiant and acetylene, are developed chiefly during an interval of time, beginning half an hour after the commencement and terminating at half the whole period of distillation, while during the remainder of the time, marsh gas and hydrogen are chiefly developed, which, while possessing little illuminating power, are most advantageous for heating purposes. ”

“ Gases, so far as they are really gaseous, not only have exactly the same properties in all directions of space, but one gas exactly resembles other gases in many qualities. All gases expand by heat, according to the same law, and by nearly the same amount; the specific heats of equivalent weights are equal, and the densities are exactly proportional to the atomic weights. All such gases obey the general law, that the volume multiplied by the pressure, and divided by the absolute temperature, is constant or nearly so. ”

“ The gas is not only comparatively indeterminate—without fixity of volume, without crystalline or other structure, etc.—but it also exhibits, in its functional manifestations, that simplicity and regularity which is characteristic of all types or primary forms. Looking, first, to the purely physical aspect of a gas—I speak, of course, only of gases which are approximately perfect, to the exclusion of vapors at low temperatures and of gases which are readily coercible: its volume expands and contracts inversely as the pressure to which it is subjected ”

“ It is possible to make the gas only as and when it is required, or it is possible in the space of an hour or so, during the most convenient part of the day, to prepare sufficient to last an entire evening, storing it in a gasholder till the moment arrives for its combustion. ”

“ But if you turn either lamp or heater too high, it will smoke anyway; you cannot get enough air through to combine with all the carbon.
The hottest flames are the blue flames. That is because in a blue flame all the carbon is burning up along with the hydrogen of the fuel—both are combining with the oxygen of the air as rapidly as possible. A gas or gasoline stove is so arranged that air is fed into the burner with the gas. You will see this in the following experiment ”

“ Yet the study of the various models and contrivances for Gas-burning there presented, fixed me in the novel faith that Gas is ultimately to be not only the main agent of illumination but the chief fuel also of all cities and villages; that the time is at hand when the head of a family, the solitary lodger, requiring either heat or light, will simply touch a bell in his own room and be supplied with the indicated quantity of Gas, whether for culinary purposes, for warmth, for light, or altogether ”

“ The rapid chemical action would raise the temperature of these gases, and thus increase their bulk immensely, which would produce an irresistible expansive force, which would increase the pressure against the sides of the cavern in which the gases were generated, and the ignition of the hydrogen would be a necessary consequence. Such an immense volume of gas being ignited, and confined, would produce such a degree of heat, as rapidly to decompose or melt the substances in its neighborhood, and set at 63 liberty a vast quantity of other gases ”

“ At first sight it appears absurd, useless, and paradoxical to lose nearly one-third of the heat which fuel can develop, by turning it into gas. Actually the advantage is enormous, especially for producing high temperatures, as is already seen from the fact that fuels rich in oxygen (for instance, wood) when damp are unable, with any kind of hearth whatever, to give the temperature required for glass-melting or steel-casting, whilst in the gas-producer they furnish exactly the same gas as the driest and most carbonaceous fuel. ”

“ There is no earthly reason why a perfect gas should not have a density far exceeding iron. Or it would be more accurate to say, the reason why it should not is earthly and does not apply to the stars.
The sun’s material, in spite of being denser than water, really is a perfect gas. It sounds incredible, but it must be so. The feature of a true gas is that there is plenty of room between the separate particles—a gas contains very little substance and lots of emptiness. ”

“ The physical peculiarity from which this results is the intensity of its heat—commonly stated at 2,000 degrees, as to our common illuminating gas—acting instantaneously throughout its mass, just as in gunpowder. The gas goes up the flue in its own flash, like the ignited charge in the barrel of a gun: the burning coals can only send, and by a leisurely messenger, namely, the moderately heated gases, and contiguous air, that rise only by the gravitation or pressure of the surrounding atmosphere. ”

“ There is no escape of combustible matter unconsumed, which is so great a nuisance [101] in all our common lights. The products of the combustion are water and carbonic acid gas [21] . The accurate and elegant experiments of Dr. W. Henry have shewn in the most satisfactory manner, that considerably less carbonic acid is produced by the flame of coal-gas, than by that of oil, tallow, or wax [22] , which [102] sufficiently refutes the absurd notions that have been circulated respecting the pernicious effects of gas-lights. ”

“ When heated in close vessels much more gas is obtained than when burnt in the open air. If moistened charcoal be put into an earthen retort and heat be applied till the retort becomes ignited; gas will be evolved, consisting partly of carbonic acid, and partly of carburetted hidrogen. A gas of similar properties is obtained by causing steam to pass through a tube filled with red-hot charcoal; by passing spirit of wine, or camphor, through red-hot tubes; by distilling oils, wood, bones, wax and tallow, or any animal or vegetable body whatever. ”

“ We know that, floating around us, these volatilized bodies exist in some material form, and numerous experiments in chemistry are calculated to convince us, that the most attenuated air is capable, with a slight change of circumstances, of being converted into the condition of solid masses. Hydrogen gas, the lightest, the most ethereal of the chemical elements, dissolves iron and zinc, arsenic, sulphur, and carbon; and from the transparent combinations thus formed, we can with facility separate those ponderous bodies. Such substances must exist in our own atmosphere ”

“ Illuminating gas is a variable mixture of hydrogen, marsh gas, olefiant gas, and other gases, and is entirely harmless when produced in the small quantities indicated in the table, and so thoroughly distributed through the air. That so much free oxygen passes off with the escaping products is an indication of the thoroughness of the combustion, and the complete oxidation of the oxidizable products. ”

“ It is thought that all matter may be passed through the three stages--iron being capable of being volatilized, and gases condensed to liquids and solids--the chief difference of these states being greater or less distance between the constituent atoms and molecules. In gas the particles are distant from each other, like gnats flying in the air; in liquids, distant as men passing in a busy street; in solids, as men in a congregation, so sparse that each can easily move about. ”

“ Now, as oxygen gas is a combination of oxygen and caloric, the caloric being in a latent state, the charcoal unites with the oxygen, and the phenomena of combustion ensue; that is, an evolution of heat and light. The caloric of the decomposed gas is given out in a free state, and, according to the theory of Dr. Thomson, (Thomson's System of Chemistry, vol. i.) the light proceeds from the burning body. We have then an instance of combustion, in which there is a combustible, a supporter of combustion, and an elevated temperature. ”

“ The processes, you see, are very different, though the result is the same, in so far as it gives us certain gaseous particles. Here, then, is the hydrogen. I showed you yesterday certain qualities of this gas; now let me exhibit you some other properties. Unlike oxygen, which is a supporter of combustion and will not burn, hydrogen itself is combustible. There is a jar full of it ”

“ I thought you said that the carbonic gas would put out the light?"
"So it will; but if three parts of air should be added to one part of the gas it will make an explosive mixture,—that is, a mixture which will burn, as there has been enough oxygen added to support combustion."
"In what way could enough air mix with the gas to make it burn?"
"By stirring it; the movement of the body might make an admixture just above the surface of the gas, which would burn, and that might mean a catastrophe for us."
"Then we are certainly stopped at this cave." ”

“ As the space occupied by the carbonic-acid gas and that occupied by the oxygen which entered into the combination is the same at the same temperature, there would be no bursting if, after combination, the temperature were the same as before; but it is a fact, which you have all observed, that fuel in burning produces heat; it is also a fact that heat expands a gas, and it is this great amount of heat, taken up by the carbonic acid formed, that produces the immense pressure in all directions. ”

“ But with gases so rich in hydrocarbons as those developed from oil it is excessively difficult to get the necessary air intimately and evenly mixed with the gas in sufficient proportion to bring about the desired result. ”