Monday, 16 March 2026

Heat and fire

If you can’t stand the heat, get out of the kitchen.
— Harry S. Truman (1884-1972).

As the heat of a fire reduces wood to ashes, the fire of knowledge burns to ashes all karma.
Bhagavad Gita, 4:37, in the translation of Eknath Easwaran, Arkana Books, 1985.

The subject of heat is one of extreme delicacy in Queensland, as indeed it is also in the other colonies. One does not allude to the heat in a host’s house any more than to a bad bottle of wine or an ill-cooked joint of meat. You may remark that it is very cool in your friend’s verandah, your friend of the moment being present, and may hint that the whole of your absent friend’s establishment is as hot as a furnace; but though you be constrained to keep your handkerchief to your brow, and hardly dare walk to the garden gate, you must never complain of the heat then and there. You may call an inn hot, or a court-house, but not a gentleman’s paddock or a lady’s drawing-room.
— Trollope, Anthony, Australia and New Zealand, London: 1873 and Brisbane: University of Queensland Press, 1967 (edited by Edwards and Joyce), 67.

I will blow out one of these candles in such a way as not to disturb the air around it … and now, if I hold a lighted taper two or three inches from the wick, you will observe a train of fire going through the air till it reaches the candle.
— Michael Faraday (1791 – 1867), On the Chemical History of a Candle, lecture given at the Royal Institution, 1860-1861.

We boil at different degrees.
— Ralph Waldo Emerson (1803-1882), Society and Solitude, ‘Eloquence’.

About ten years ago I read in the ‘History of Sciences’ issued by the Royal Academy of Paris, that the celebrated Amontons, using a thermometer of his own invention, had discovered that water boils at a fixed degree of heat. I was at once inflamed with a great desire to make for myself a thermometer of the same sort, so that I might with my own eyes perceive this beautiful phenomenon of nature and be convinced of the truth of the experiment.

I therefore attempted to construct a thermometer, but because of my lack of experience in its construction, my efforts were in vain, though they were often repeated … It then came into my mind what that most careful observer of natural phenomena had written about the correction of the barometer; for he had observed that the height of the column of mercury in the barometer was a little (though noticeably enough) altered by the varying temperature of the mercury. From this I gathered that a thermometer might perhaps be constructed with mercury, which would be easy to construct, and by which it might be possible to carry out the experiment which I so greatly wished to try.

When a thermometer of that sort was made (perhaps imperfect in many ways) the result answered my prayer; and with great pleasure of mind I observed the truth of the thing.

… the degree 48 … in my thermometers holds the middle place between the limit of the most intense cold obtained artificially in a mixture of water, of ice and of sal-ammoniac or even of sea-salt, and the limit of the heat which is found in the blood of a healthy man.
— Gabriel Daniel Fahrenheit (1686 – 1736), Philosophical Transactions, Vol. 33, 1734, 1.

It frequently happens that in the ordinary affairs and occupations of life, opportunities present themselves of contemplating some of the most curious operations of Nature; and very interesting philosophical experiments might often be made, almost without trouble or expense, by means of machinery contrived for the mere mechanical purpose of the arts and manufactures.

I have frequently had occasion to make this observation; and am persuaded that a habit of keeping the eyes open to everything that is going on in the ordinary course of the business of life has oftener led, as it were by accident … to useful doubts and sensible schemes for investigation and improvement, than all the more intense meditations of philosophers in the hours expressly set apart for study.

It was by accident that I was led to make the experiments of which I am about to give an account …

Being engaged lately in superintending the boring of cannon in the workshops of the military arsenal at Munich, I was struck by the very considerable degree of Heat (much greater than that of boiling water, as I found by experiment) of the metallic chips separated from it by the borer.

… according to the modern doctrines of latent Heat, and of caloric, the capacity for Heat of the parts of the metal, so reduced to chips, ought not only to be changed, but the change undergone by them should be sufficiently great to account for all the Heat produced.

But no such change had taken place … I could not determine whether any, or what change had been produced in the metal, in regard to its capacity for Heat, by being reduced to chips by the borer.
— Benjamin Thompson (Count Rumford) (1753 – 1814), Philosophical Transactions (vol. 88), 1798.

And by several experiments which have been made with great care, and with the assistance of thermometers, it has been demonstrated, that the saving of fuel, arising from these improvements of Fire-places, amounts in all cases to more than HALF, and in many cases to more than TWO THIRDS of the quantity formerly consumed.
— Benjamin Thompson (Count Rumford) (1753 – 1814), Essays, Political, Economical and Philosophical, Volume 1, 308 – 9.

Two fixed points of temperature being chosen according to Sir Isaac Newton’s suggestions, by particular effects on a particular substance or substances, the difference of these temperatures is to be called unity, or any number of units or degrees as may be found convenient. The particular convention is, that the difference of temperatures between the freezing- and boiling-points of water under standard atmospheric pressure shall be called 100 degrees. The determination of the absolute temperatures of the fixed points is then to be effected by means of observations indicating the economy of a perfect thermodynamic engine, with the higher and lower respectively as the temperatures of its source and refrigerator. The kind of observation best adapted for this object was originated by Mr. Joule, whose work in 1844 laid the foundation of the theory, and opened the experimental investigation; and it has been carried out by him, in conjunction with myself … The best result that we have yet been able to obtain is, that the temperature of water is 273.7 on the absolute scale; that of the boiling point being consequently 373.7.
— Lord Kelvin [William Thomson] (1824 – 1907), Philosophical Magazine, October 1848.

What is accomplished by fire is alchemy, whether in the furnace or kitchen stove.
— Paracelsus (1493-1541)

Lucifer matches, although first-rate articles at home, are often from damp or from wind utterly useless in the bush. Small tinder-boxes suitable for this kind of service may be purchased cheaply in Sydney, and a sort of fungus which grows upon dead timber, and is well known to most colonists by the name of “punk,” makes, when scorched, the best tinder. The ordinary German tinder, however, is very good. By its aid a few pieces of dry bark may be lighted, and with the addition of a twig or two and some dry leaves, there is speedily sufficient foundation to “build,” as the phrase is, a large fire. The blacks procure fire very readily by means of the grass tree, but few whites succeed in doing this, until they have seen it practised several times by their sable brethren.

The best mode is this. Cut a piece of the dried stalk of the grass tree in two; point one half, and hollow out in a cup shape one end of the other half, so that the pointed part may fit as nearly as possible the hollowed part; put the hollowed piece between the knees and inserting the point of the other, which is held between the palms of the hands, twirl it rapidly and regularly round by moving the hands backwards and forwards. If this is dexterously managed the friction will soon produce fire.
— The Sydney Morning Herald, Saturday 13 September 1851, 4.

There was pushing and pulling and officious cries. Ralph moved the lenses back and forth, this way and that, until a glossy white image of the declining sun lay on a piece of rotten wood. Almost at once a thin trickle of smoke rose up and made him cough. Jack knelt too and blew gently, so that the smoke drifted away, thickening, and a tiny flame appeared. The flame, nearly invisible in that bright sunlight, enveloped a small twig, grew, was enriched with colour and reached up to a branch which exploded with a crack. The flame flapped higher and the boys broke into a cheer.
— William Golding (1912 –1993), Lord of the Flies, chapter 2, Faber edition (1974).

I may here describe the usual method of encampment on such expeditions. A convenient spot being selected, if possible, to windward of a large fallen half-burned tree, a few branches and bushes are placed in a semicircular form, as a defence against the night wind; the log is kindled, and soon forms a blazing fire, which, being too fierce for cooking, a smaller one is used for that purpose. After supper, each rolls himself in his blanket, and, with his feet towards the fire, soon falls asleep.
— Wilson, T. B., Narrative of a Voyage Round the World. London: Sherwood, Gilbert and Piper, 1835, London: Dawson’s of Pall Mall, 1968, 246.

‘Now we shall see,’ I said: I carefully lifted the cathode jar, and holding it with its open end down, lit a match and brought it close. There was an explosion, small but sharp and angry, the jar burst into splinters (luckily, I was holding it level with my chest and not higher), and there remained in my hand, as a sarcastic symbol, the glass ring of the bottom.
— Primo Levi (1919 – 1987), ‘Hydrogen’ in The Periodic Table (1985)

I perceived that this opinion was a mistake, and that the quantities of heat which different kinds of matter must receive, to reduce them to an equilibrium with each one another, or to raise their temperature by an equal number of degrees, are not in proportion to the quantity of matter in each.
— Joseph Black (1728-1799), Lectures on the Elements of Chemistry (1803)

Heat passes from one body into another through an intervening substance, as from a vessel of water through the glass bulb of a thermometer into the mercury inside the bulb. This process, by which heat passes from hotter to colder parts of a body is called the conduction of heat.
— James Clerk Maxwell (1831-1879), Theory of Heat, 10th edition, 1891 (revised by Lord Rayleigh), 7.


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