Chapter XVI: Part 16

Following are three columns of figures. The first represents atmospheres of pressure—_i.e._, taking our atmospheric pressure when it supports 30 inches of mercury in the barometer tube as a unit, that pressure is doubled, trebled, etc., up to twenty times in the first column. The second column states the temperature at which water boils when under the different pressures thus indicated. The third column, which is the subject for special study just now, shows how much we must rise the temperature of the water in order to make it boil as we go on adding atmospheres of pressure; or, in other words, the increase of temperature due to each increase of one atmosphere of pressure. The figures are founded on the experiments of Regnault.

Pressure in Temperature, F. Rise of Temperature
Atmospheres ° for each additional
Atmosphere
1 212
2 249·5 37·5
3 273·3 23·8
4 291·2 17·9
5 306·0 14·8
6 318·2 12·2
7 329·6 11·4
8 339·5 9·9
9 348·4 8·9
10 356·6 8·2
11 364·2 7·6
12 371·1 6·9
13 377·8 6·7
14 384·0 6·2
15 390·0 6·0
16 395·4 5·4
17 400·8 5·4
18 405·9 5·1
19 410·8 4·9
20 415·4 4·6

It may be seen from the above that, with the exception of one irregularity, there is a continual diminution of the additional temperature which is required to overcome an additional atmosphere of pressure, and if this goes on as the pressure and temperatures advance, we may ultimately reach a curious condition—a temperature at which additional pressure will demand no additional temperature to maintain the gaseous state; or, in other words, a temperature may be reached at which no amount of pressure can condense steam into water, or at which the gaseous and liquid states merge or become indifferent.

But we must not push this mere numerical reasoning too far, seeing that it is quite possible to be continually approaching a given point, without ever reaching it, as when we go on continually halving the remaining distance. The figures in the above do not appear to follow according to such a law—nor, indeed, any other regularity. This probably arises from experimental error, as there are discrepancies in the results of different investigators. They all agree, however, in the broad fact of the gradation above stated. Dulong and Arago, who directed the experiments of the French Government Commission for investigating this subject, state the pressure at 20 atmospheres to be 418·4, at 21 = 422·9, at 22 = 427·3, at 23 = 431·4, and at 24 atmospheres, their highest _experimental_ limit, 435·5, thus reducing the rise of temperature between the 23d and 24th atmospheres to 4·1.

If we could go on heating water in a transparent vessel until this difference became a vanishing quantity, we should probably recognize a visible physical change coincident with this cessation of condensibility by pressure; but this is not possible, as glass would become red-hot and softened, and thus incapable of bearing the great pressure demanded. Besides this, glass is soluble in water at these high temperatures.

If, however, we can find some liquid with a lower boiling-point, we may go on piling atmosphere upon atmosphere of elastic expansive pressure, as the temperature is raised, without reaching an unmanageable degree of heat. Liquid carbonic acid, which, under a single atmosphere of pressure, boils at 112° below the zero of our thermometer, may thus be raised to a temperature having the same relation to its boiling-point that a red-heat has to that of water, and may be still confined within a glass vessel, provided the walls of the vessel are sufficiently thick to bear the strain of the elastic outstriving pressure. In spite of its brittleness glass is capable of bearing an enormous strain _steadily applied_, as may be proved by trying to break even a mere thread of glass by direct pull.

Dr. Andrews thus treated carbonic acid, and the experiment, as I have witnessed its repetition, is very curious. A liquid occupies the lower part of a very strong glass tube, which appears empty above. But this apparent void is occupied by invisible carbonic acid gas, evolved by the previous boiling of the liquid carbonic acid below. We start at a low temperature—say 40° Fahr. Then the temperature is raised; the liquid boils until it has given off sufficient gas or vapor to exert the full expansive pressure or tension due to that temperature. This pressure stops the boiling, and again the surface of the liquid is becalmed.

This is repeated at a higher temperature, and thus continued until we approach nearly to 88° Fahr., when the surface of the liquid loses some of its sharp outline. Then 88° is reached, and the boundary between liquid and gas vanishes; liquid and gas have blended into one mysterious intermediate fluid; an indefinite fluctuating something is there filling the whole of the tube—an etherealized liquid or a visible gas. Hold a red-hot poker between your eye and the light; you will see an upflowing wavy movement of what appears like liquid air. The appearance of the hybrid fluid in the tube resembles this, but is sensibly denser, and evidently stands between the liquid and gaseous states of matter, as pitch or treacle stands between solid and liquid.

The temperature at which this occurs has been named by Dr. Andrews the “_critical temperature_”; here the gaseous and liquid states are “_continuous_,” and it is probable that all other substances capable of existing in both states have their own particular critical temperatures.

Having thus stated the facts in popular outline, I shall conclude the subject by indulging in some speculations of my own on the philosophy of these general facts or natural laws, and on some of their possible consequences.

As already stated, the conversion of water into steam under ordinary atmospheric pressure demands 966·6° of heat over and above that which does the work of raising the water to 212°, or, otherwise stated, as much heat is at work in a given weight of steam at 212°, as would raise the same quantity of water to 1178·6° if it remained liquid.

James Watt concluded from his experiments that a given weight of steam, whatever may be its density, or, in other words, under whatever pressure it may exist, contains the same quantity of heat. According to this, if we reduced the pressure sufficiently to bring down the boiling-point to 112°, instead of 212°, the latent heat of the steam thus formed would be 1066·6° instead of 966·6°, or if, on the other hand, we placed it under sufficient pressure to raise the boiling-point to 312°, the latent heat of the steam would be reduced to 866·6°, _i.e._, only 866·6° more would be required to convert the water into steam. If the boiling-point were 412°, as it is between 19 and 20 atmospheres of pressure, only 766·6° more heat would be required, and so on, till we reached a pressure which raised the boiling-point to 1178·6°; the water would then become steam without further heating, _i.e._, the critical point would be reached, and thus, if Watt is right, we can easily determine, theoretically, the critical temperature of water.[36]

Mr. Perkins, who made some remarkable experiments upon very high pressure steam many years ago, and exhibited a steam gun at the Adelaide Gallery, stated that red-hot water does not boil; that if the generator be sufficiently strong to stand a pressure of 60,000 lbs. load on the safety-valve, the water may be made to exert a pressure of 56,000 lbs. on the square inch at a cherry-red heat without boiling. He made a number of rather dangerous experiments in thus raising water to a red-heat, and his assertion that red-hot water does not boil is curious when viewed in connection with Dr. Andrews’ experiments.

I cannot tell how he arrived at this conclusion, having been unable to obtain the original record of his experiments, and only quote the above second hand. It is worthy of remark that the temperature he names is about 1170°, or that which, if Watt is right, must be the critical temperature of the water. Perkins’ red-hot water would not boil, being then in the intermediate condition.

So far, we have a nice little theory, which not only shows how the critical state of water must be reached, but also its precise temperature; but all this is based on the assumption that Watt made no mistake.

Unfortunately for the simplicity of this theory, Regnault states that _his_ experiments contradict those of Watt, and prove that the latent heat of steam does not diminish just in the same degree as the boiling-point is raised, but that instead of this the diminution of the latent heat progresses 30½ per cent more slowly than the rise of temperature, so that, instead of the latent heat of steam between boiling-points of 212° and 312° falling from 966·6° to 866·6° it would only fall to 895·1° or 69·5° of latent heat for every 100° of temperature.

If this is correct, the temperature at which the latent heat of steam is reduced to zero is much higher than 1178·6°, and is, in fact, a continually receding quantity never absolutely reached; but I am not prepared to accept these figures of Regnault as implicitly as is now done in text-books (I was nearly saying “as is now the fashion”), seeing that they are not the actual figures obtained by his experiments, but those of his “empirical formulæ” based upon them. His actual experimental figures are very irregular; thus, between steam temperature of 171·6° and 183·2° a difference of 11·6°, the experimental difference in the latent heat came out as 4·7°; between steam temperature of 183·2° and 194·8°, or 11·6° again, the latent heat difference is tabulated as 8·0°.

Regnault’s experiments were not carried to very high temperatures and pressures, and indicate that as these advance the deviation from Watt’s law diminishes, and may finally vanish at about 1500° or 1600°, where the latent heat would reach zero, and there, according to the above, the critical temperature would be reached. Any additional heat applied after this will have but one function to perform, viz., the ordinary work of increasing the bulk of the heated body without doing anything further in the way of conferring upon it any new self-repulsive properties.

Our notions of solids, liquids, and gases are derived from our experiences of the state of matter here upon this earth. Could we be removed to another planet, they would be curiously changed. On Mercury water would rank as one of the condensible gases; on Mars, as a fusible solid; but what on Jupiter?

Recent observations justify us in regarding this as a miniature sun, with an external envelope of cloudy matter, apparently of partially condensed water, but red-hot, or probably still hotter within. His vaporous atmosphere is evidently of enormous depth, and the force of gravitation being on his visible outer surface two and a half times greater than that on our earth’s surface, the atmospheric pressure in descending below this visible surface must soon reach that at which the vapor of water would be brought to its critical condition. Therefore we may infer that the oceans of Jupiter are neither of frozen liquid nor gaseous water, but are oceans or atmospheres of critical water. If any fish-birds swim or fly therein they must be very critically organized.

As the whole mass of Jupiter is three hundred times greater than that of the earth, and its compressing energy towards the centre proportional to this, its materials, if similar to those of the earth and no hotter, would be considerably more dense, and the whole planet would have a higher specific gravity; but we know by the movement of its satellites that, instead of this, its specific gravity is less than a fourth of that of the earth. This justifies the conclusion that it is intensely hot, for even hydrogen, if cold, would become denser than Jupiter under such pressure.

As all elementary substances may exist as solids, liquids, or gases, or critically, according to the conditions of temperature and pressure, I am justified in hypothetically concluding that Jupiter is neither a solid, a liquid, nor a gaseous planet, _but a critical planet_, or an orb composed internally of dissociated elements in the critical state, and surrounded by a dense atmosphere of their vapors, and those of some of their compounds, such as water. The same reasoning applies to Saturn and the other large and rarefied planets.

The critical temperature of the dissociated elements of the sun is probably reached at the base of the photosphere, or that region revealed to us by the sun-spots. When I wrote “The Fuel of the Sun,” thirteen or fourteen years ago, I suggested, on the above grounds, the then heretical idea of the red-heat of Jupiter, Saturn, Uranus, and Neptune, and showed that all such compounds as water must be dissociated at the base of the sun’s atmosphere; but being then unacquainted with the existence of this critical state of matter, I supposed the dissociated elements to exist as gases with a small solid nucleus or kernel in the centre.

Applying now the researches of Dr. Andrews to the conditions of solar existence, as I formerly applied the dissociation researches of Deville, I conclude that the sun has no nucleus, either solid, liquid, or gaseous, but is composed of dissociated matter in the critical state, surrounded, first, by a flaming envelope due to the re-combination of the dissociated matter, and outside of this another envelope of vapors due to this combination.

MURCHISON AND BABBAGE.

The curious contrast of character presented by these two eminent men, and the very different course of their lives, conveys a striking lesson to all those superficial thinkers and unthinking talkers who make sweeping generalizations concerning human character; who assume as a matter of course that any man who writes poetry must be merely a dreamer of day-dreams, incapable of transacting any practical daily business, and not at all reliable in money matters; whose eyes are always “in a fine frenzy rolling”; that he is, in short, a sort of amiable, harmless lunatic. All actors, according to such people, are dissipated spendthrifts; and if Sims Reeves, or any other public performer, is prevented by delicate larynx or other indisposition from appearing, they look knowing, shrug their shoulders, wink wisely, and assume, without the faintest shadow of evidence, that he is drunk.

In like manner they set up a typical philosopher of their own manufacture, and attribute his imaginary character to all who devote themselves to science. Their philosopher is a musty, dried-up, absent-minded pedant, whose ordinary conversation is conducted in words of seven syllables, who is always lost in profound abstractions; takes no interest in common things; regards music, dancing, play-acting, poetry, and every cheerful pursuit as frivolous and contemptible—a creature who never makes a joke, seldom laughs, and who in matters of business is even more incapable than the poet.

The singular contrast of character presented by Babbage and Murchison affords at once a most complete refutation of such generalizations. Here were two men, both philosophers, one the very type of amiability, suavity, and all conceivable polish, the very perfection of a courtier, but differing from the vulgar courtier of the Court in this respect, that his high-toned courtesy was not bestowed upon kings only, but also upon all his human brethren, and with especial gracefulness upon those whose rank was below his own.

I doubt whether there is any man now living, or has lived during this generation, that could equal Sir Roderick Murchison in the art of distributing showers of compliments upon a large number of different people in succession, and making each recipient delightfully satisfied with himself. In his position as Chairman to the Geological Section of the British Association, he did this with marvelous tact, without the least fulsomeness or repetition, or any display of patronizing. Every man who read a paper before that section was better than ever satisfied with the great merits and vast importance of his communication, after hearing the Chairman’s comments upon it. None but a most detestably strong-minded and logical brute could resist the insinuating flattery of Sir Roderick.

How different was poor Babbage! Who that attends any sort of scientific gatherings has not seen Sir Roderick? but who in the world, excepting the organ-grinders and the police magistrate has ever seen Babbage, or even his portrait? What a contrast between the seclusion and the public existence; between the hedgehog bristles and the velvet softness, of the one and the other!

Those who were on intimate terms with Babbage (I have never met or heard of such a person) could probably tell us that all his irritability and roughness were outside, and that, in the absence of organ-grinders, he was a kind and amiable gentleman; but, even admitting this, the contrast between the two philosophers is as great as could well be found between any two men following the most widely divergent studies or professions.

Those who would reply that mathematics and geology are such different studies have only to go a little further back on the death-roll, and they will find the name of De Morgan, a pure mathematician, like Babbage. He was a man of exuberant fun and humor, and so far from hating music of either a humble or pretentious character, was a highly accomplished musician, both theoretical and practical, and if we are to believe confidential communications, one of his favorite instruments was the penny whistle, on which he was a most original and peculiar performer.

I had not intended to reprint the above, which was written just after the death of Murchison and Babbage, but the comments that have recently followed the death of Darwin induce me to do so.

Many have expressed their surprise at the unanimous expressions of Darwin’s friends concerning the geniality of his disposition, his gentleness, cheerfulness; his _genuine_ humility and simplicity of character.

A third type of character is here presented, and that which corresponds most correctly with the true ideal of a modern philosopher, also represented by that great master of experimental science, Faraday. In both of these there was the full measure of Murchison’s amiability, but without the courtly polish of the ex-soldier. Philosophic meditation and close application to original research may, and often does, induce a certain degree of shyness due to a consciousness of the social disqualification which arises from that inability to fulfil all the demands for small attentions which constitute conventional politeness; a disability due to habits of consecutive thought and mental abstraction.

A sensitive and amiable man would suffer much pain on finding that he had neglected to supply the small wants of the lady sitting next to him at a dinner party, and would withdraw himself from the risk of repeating such unwitting rudeness. This holding back from ordinary society, though really due to a conscientious sense of social duty and tender regard for the feelings of others, is too often referred to a churlish unsociality or arrogant assumption of superiority.

If Newton really did mistake the lady’s finger for a tobacco-stopper, depend upon it the pain he suffered was far more acute than that which he inflicted, and was suffered over and over again whenever the incident was recollected.

ATMOSPHERE _versus_ ETHER.

One of the most remarkable meteors of which we have a reliable record appeared on February 6, 1818. Several accounts of it were published, the fullest being that in _The Gentleman’s Magazine_ of the time. (I may here add, parenthetically, that one reason why I have especial pleasure in writing these notes is that they contribute something towards the restoration of the ancient status of this magazine, which was at one time the only English serial that ventured upon any notable degree of exposition of _popular_ science.)

Upon the data supplied by this account, Mr. Joule has calculated the height of the meteor to have been 61 miles above the surface of the earth, and he states that “this meteor is one of the few that have been seen in the daytime, and is also interesting as having been one of the first whose observation afforded materials for the estimation of its altitude.” It was seen in the neighborhood of Cambridge at 2 P.M., also at Swaffham in Norfolk, and at Middleton Cheney near Banbury. The distance between this and Cambridge is sufficient to afford a measurement of its height, provided its position above the horizon at both places was determined with tolerable accuracy.

According to the orthodox text-books, the atmosphere of this earth terminates at a height of about 45 or 50 miles, or, if not absolutely ended there, it ceases to be of appreciable density anywhere above this elevation.

But here we have a fact which flatly contradicts the calculation. At 61 miles above the earth’s surface there must be atmospheric matter of sufficient density to offer to the passage of this meteor through it an amount of resistance which produced an intense white heat, visible by its luminosity in broad daylight.

In the above-quoted paper, read by Mr. Joule before the Manchester Literary and Philosophical Society on December 1, 1863, he refers to subsequent observations and estimates 116 miles as “the elevation at which meteors in general are first observed”—_i.e._, where our atmosphere is sufficiently dense to generate a white-heat by the resistance it offers to the rapidly flying meteor.

It is curious to observe how, in dealing with actual physical facts, a mathematician of the solid practical character of Joule becomes compelled to practically throw overboard the orthodox theory of limited atmospheric extension. Here, in making his calculations of the resistance of atmospheric matter at this elevation, he bases them on the assumption of a decrease of density at the rate of “one quarter for every seven miles,” and indicates no limit at which this rate shall vary. Very simple arithmetic is sufficient to show that this leads us to the unlimited atmospheric extension, for which I have contended we may go on for ever taking off a quarter at every seven miles, and there will still remain the three quarters of the quantity upon which we last operated, or, more practically stated, we shall thus go on seven after seven until we reach the boundaries of the atmospheric grasp of the gravitation of some other sphere.

Surely the time has arrived for the full reconsideration of this fundamental question of whether the universe is filled with atmospheric matter or is the vacuum of the molecular mathematicians plus the imaginary “ether,” which has been invented by its mathematical creators only to extricate them from the absurd dilemma into which they are plunged when they attempt to explain the transmission of light and heat by undulations traveling through space containing nothing to undulate.

They have filled it with immaterial matter evolved entirely from their own consciousness, which they have gratuitously endowed with whatever properties are required for the fitting of their theories—properties that are self-contradictory and without any counterpart in anything seen or known outside of the fertile imagination of these reckless theorists.

We know of nothing that can penetrate every form of matter without adding either to its weight or its bulk; we know of nothing that can communicate motion to ponderable matter without itself being ponderable—_i.e._, having the primary property of matter, viz., mass, or weight, and consequent _vis viva_ when moving; we know of nothing that can set bodies in motion without proportionally resisting the motion of bodies through it; and if the waving of the ether is (as Tyndall describes it) “as real and as truly mechanical as the breaking of sea-waves upon the shore,” the material of the breakers must be like the “jelly” to which he compares it, and have some viscosity, or resistance to penetration, or pushing aside.

We have not a shadow of direct evidence of the existence of the “interatomic” spaces occupied by the other, and in the midst of which the atoms are made to theoretically swing, nor even of the existence of the atoms themselves.

The “ether” of to-day, with its imaginary penetration and its material action without material properties, has merely taken the place of the equally imaginary phlogiston, caloric, electric, and magnetic fluids, the “imponderables” of the past. I have little doubt that ere long the modern modification of these physical superstitions will share their fate, and we shall all adopt the simple conception that heat, light, end electricity are, like sound, merely transmissible states or affections of matter itself regarded bodily, as it is seen and felt to exist.

This may possibly throw a good many mathematicians out of work—or into more useful work; but, however that may be, it will certainly aid the general diffusion of science as the intellectual inheritance of every human being. At present the explanations of the simple phenomena of light and heat are incomparably more difficult to understand and to account for than the facts which they attempt to elucidate.

A NEGLECTED DISINFECTANT.

When the household of our grandmothers was threatened with infection, the common practice was to sprinkle brimstone on a hot shovel or on hot coals on a shovel, and carry the burning result through the house. But now this simple method of disinfecting has gone out of fashion without any good and sufficient reason. The principal reason is neither good nor sufficient, viz., that nobody can patent it and sell it in shilling and half-crown bottles.

On September 18th last, M. d’Abbadie read a paper at the Academy of Sciences on “Marsh Fevers,” and stated that in the dangerous regions of African river mouths immunity from such-fevers is often secured by sulphur fumigations on the naked body. Also that the Sicilian workers in low ground sulphur mines suffer much less than the rest of the surrounding population from intermittent fevers. M. Fouqué has shown that Zephyria (on the volcanic island of Milo or Melos, the most westerly of the Cyclades), which had a population of 40,000 when it was the centre of sulphur-mining operations, became nearly depopulated by marsh fever when the sulphur-mining was moved farther east, and the emanations prevented by a mountain from reaching the town. Other similar cases were stated.

It is well understood by chemists that bleaching agents are usually good disinfectants; that which can so disturb an organic compound as to destroy its color, is capable of either arresting or completing the decompositions that produce vile odors and nourish the organic germs or ferments which usual accompany, or, as some affirm, cause them. Sulphurous acid is, next to hypochlorous acid, one of the most effective bleaching agents within easy reach.

I should add that sulphurous acid is the gas that is _directly_ formed by burning sulphur. By taking up another dose of oxygen it becomes sulphuric acid, which, combined with water, is oil of vitriol. The bleaching and disinfecting action of the sulphurous acid is connected with its activity in appropriating the oxygen which is loosely held or being given off by organic matter. Chlorine and hypochlorous acid (which is still more effective than chlorine itself) act in the opposite way, so do the permanganates, such as Condy’s fluid, etc. They supply oxygen in the presence of water. It is curious that opposite actions should produce like results. A disquisition on this and its suggestions would carry me beyond the limits of a note.

ANOTHER DISINFECTANT.

The above-named disinfectants are objectionable on account of their own odors and their corrosive action. Both sulphurous acid and hypochlorous acid (the active principle of the so-called “chloride of lime”) have a disagreeable habit of rusting iron and suggesting antique green bronzes by their action on brass ornaments. Under serious conditions this should be endured, but in many cases where the danger is not already developed, the desired end may be attained without these annoyances.

Sulphate of copper, which is not patented or “brought out” by a limited company, may be bought at its fair retail value of 6_d._ or less per lb. (the oil-shop name for it is “blue vitriol”), in crystals, readily soluble in water.

I have lately used it in the case of a trouble to which English households are too commonly liable, and one that has in many cases done serious mischief. The stoppage of a soil-pipe caused the overflow of a closet, and a consequent saturation of floor boards, that in time would probably have developed danger by nourishing and developing those germs of bacteria, bacilli, etc., which abound in the air, and are ready to increase and multiply wherever their unsavory food abounds.

By simply mopping the floor with a solution of these green crystals, and allowing it to soak well into the pores of the wood, they cease to become a habitat for such microscopic abominations. The copper-salt poisons the poisoners.

Dr. Burg goes so far as to recommend that building materials, articles of furniture, and clothing, etc., should be injected with sulphate of copper, in order to avert infection, and in support of this refers to the immunity of workers in copper from cholera, typhoid fever, and infectious diseases generally.

I agree with him to the extent of suggesting the desirability of occasionally mopping house floors with this solution. Its visible effects on the wood are first to stain it with a faint green tinge which gradually tones down to a brown stain, giving to deal the appearance of oak, a change which has no disadvantage from an artistic point of view. If the wood is already tainted with organic matter capable of giving off sulphureted hydrogen, the darkening change is more rapid and decided, owing to the formation of sulphide of copper.

The solution of sulphate should not be put into iron or zinc vessels, as it rapidly corrodes them, and deposits a non-adherent film of copper. It will even disintegrate common earthenware, by penetrating the glaze, and crystallizing within the pores of the ware, but this is a work of time (weeks or months). Stoneware resists this, and wooden buckets may be used safely. It is better to keep the crystals and dissolve when required. Ordinary earthenware may be used with impunity if washed immediately afterwards.

ENSILAGE.

This subject has been largely expounded and discussed lately in the _Times_ and other newspapers. As most of my readers are doubtless aware, it is simply a substitute for haymaking, by digging pits, paving and building them round with stone or concrete, then placing the green fodder therein and covering it over with sufficient earth to exclude the air.

We are told that very inferior material (such as coarse maize grass mixed with chaff) when thus preserved gives better feeding and milking results than good English hay.

I may mention a very humble experience of my own that bears upon this. When a boy, I was devoted to silkworms, and my very small supply of pocket-money was over-taxed in the purchase of exorbitantly small pennyworths of mulberry leaves at Covent Garden. But a friend in the country had a mulberry tree, and at rather long intervals I obtained large supplies, which, in spite of all my careful wrapping in damp cloths, became rotted in about ten days. I finally tried digging a hole and burying them. They remained fresh and green until all my silkworms commenced the working and fasting stage of their existence. This was ensilage on a small scale.

The correspondence in the newspapers has suggested a number of reasons why English farmers do not follow the example of their continental neighbors in this respect; climate, difference of grasses, etc., etc., are named, but the real reason why this is commercially impossible, and farming, properly so called, is becoming a lost art in England (mere meadow or prairie grazing gradually superseding it) is not named in any part of the discussion that I have read.

I refer to the cause which is abolishing the English dairy, which drives us to the commercial absurdity of importing fragile eggs from France, Italy, Spain, etc., apples from the other side of the Atlantic, tame house-fed rabbits from Belgium, and so on, with all other agricultural products which are precisely those we are _naturally_ best able to produce at home; I mean _those demanding a small area of land and a proportionately large amount of capital and labor_. A poultry or rabbit farm, acre for acre, demands fully ten times the capital, ten times the labor, and yields ten times the produce obtained by our big-field beef and mutton graziers.

The scientific and economic merits of ensilage are probably all that is claimed for it, and it is especially adapted for our uncertain haymaking climate, but what farmer who is merely a lodger on the land, holding it as an annual tenant-at-will or under a stinted beggarly lease of 21 years, would expend his capital in building a costly _silo_, which becomes by our feudal laws and usages the absolute property of the landlord?

Our tenant farmers employ the latest and best achievements of engineering science in the form of implements, but take care that they shall be _upon wheels_, or otherwise non-fixtures, and use rich chemically prepared manures, provided they are not permanent, while they abstain from improvements which involve any serious outlay in the form of fixtures on the land. Those who lecture them about their want of enterprise should always remember that their condition is merely a form of feudal serfdom, tempered by the possession of capital, and that all their agricultural operations are influenced by a continual struggle to prevent their capital from falling into the hands of the feudal lord. Anybody who has ever read an ordinary form of English farm-lease, with its prohibitions concerning the sale of hay and straw, and restrictions to “four-course,” or other mode of cultivation, must see the hopelessness of any development of British agriculture comparable to that of British commerce and manufactures.

Imagine the condition of a London shopkeeper or Midland manufacturer holding his business premises as a yearly tenant, liable at six months’ notice to quit, with confiscation of all his business fixtures.

THE FRACTURE OF COMETS.

The view of the constitution of comets expounded in one of my notes of April last, viz., that they are meteoric systems consisting of a central mass, or masses, round which a multitude of minor bodies are revolving like satellites around their primary, is strongly confirmed by the curious proceedings of the present comet, which proceedings also justify my last note of last month pointing out the omission of our astronomers, who have neglected the positive and irregular repulsive action of the sun upon comets, that, like the great comets of 1843, 1880, and 1882, come within a few hundred thousand miles of the visible solar surface.

The solar prominences are stupendous eruptions from the sun, consisting, as the spectroscope demonstrates, of hydrogen flames and incandescent metallic vapors ejected with furious violence to visible distances ranging from ten or twenty to above three hundred thousand miles, but this flame shown by the spectroscope is but the flash of the gun, the actual ejection proceeding vastly farther, far beyond the limits of the corona, as described in last month’s notes. These eruptions are so abundant that Secchi alone observed and recorded 2767 in one year (1871). Speaking generally, the sun is never free from them, and they proceed from all parts of the sun, but most abundantly from the sun-spot zones.

A system of meteoric bodies such as I suppose to form a comet (I mean the comet as it exists in space before the generation of its tail, which is only formed as it approaches the sun) could not approach so near to the sun as did the present comet at perihelion, without encountering more or less of these furious blasts the flash of some of which have been seen to move with a measurable mean velocity of above 300 miles per second, and a probable maximum velocity sufficient to eject solid matter beyond the reclaiming grasp of solar gravitation.

It is evident that such a meteoric system as I suppose to constitute a comet would, in the course of a rapid perihelion flight crossing these outblasts, be liable to various degrees of ejection in different parts, that would disturb its original structure by blowing some of its constituents out of their orbits, or even quite away from the control of the feeble gravitation of the general meteoric mass, and thus effecting a rupture of the comet.

Now such a disintegration or dispersion of the present comet has been actually observed. Several able observers have described a breaking of the head of this comet shortly after its perihelion passage. Commander Sampson’s observations with the great 26-inch equatorial telescope of the Washington Naval Observatory are very explicit. On October 25 he saw the nucleus as a single well-defined globular body. On November 3, with the same telescope, he saw a triple nucleus, due to the formation of two additional minor bodies. These were more distinctly seen on November 6. Mr. W. R. Brooks, of New York, saw a detached fragment of the comet which afterwards faded out of view. Professor Schmidt observed another and similar fragment which has likewise disappeared.

All these observations indicate disruption due to some disturbing force, acting with different degrees of violence upon different portions of the comet.

Minor disturbances of this kind will, I think, account for the trail of meteoric bodies which Schiaparelli has shown to follow the paths of other comets. A great disturbance might give quite a new orbit to the meteoric fragments.

These considerations suggest another and a curious view of the question of possible cometary collision with the sun, viz., that a comet might be traveling in such an orbit as to make it mathematically due to plunge obliquely beneath the solar surface at its next perihelion; but on its approach to the surface of the sun it might encounter so violent an outrush of solar-prominence matter as to drive it bodily out of its course, and avert the threatened peril to its existence.

THE ORIGIN OF COMETS.

We read in story-books of uncomfortable people who have cherished a guilty secret in their bosoms, that it has “gnawed their vitals,” until at last they have carried it to the grave. I have such a secret that does the gnawing business whenever I write or speak of comets, concerning the origin of which I am guilty of an hypothesis that has hitherto been cherished as aforesaid from the very shame of adding another to an already exaggerated heap of speculations on celestial physics.

It assumes, in the first place, that all the other suns which we see as stars are constituted like our own sun; that they eject great eruptions similar to the prominences above described, and even of vastly greater magnitude, as in the case of the flashing stars that have excited so much wonderment among astronomers, but which I regard simply as suns like ours, subject, like ours, to periodic maximum and minimum activities, but of greater magnitude.

If such is the case, some of the prominence matter or vaporous constituents of these suns must be ejected with much greater proportional violence than are those from our sun. But those from our sun have been proved to rush out on some occasions with a velocity so great that the solar gravitation cannot bring them back. If such is ever the case with the explosions of our sun, it must be of frequent occurrence with the greater explosions of certain stars, and therefore vast quantities of meteoric matter are continually ejected into space, and traveling there until they come within the gravitation domain of some other sun like ours, when they will necessarily be bent into such orbits as those of comets.

But what will be the nature of this meteoric matter?

If from our sun, it would be a multitude of metallic hailstones, due to the condensation of the metallic vapor by cooling as it leaves the sun, and such meteoric hail would correspond to the meteoric stones that fall upon our earth, and which, for reasons stated in “The Fuel of the Sun,” I believe to be of solar origin. Besides these, there would be ice-hail, such as Schevedorf claims to be meteoric.

A star mainly composed of hydrogen and carbon, or densely enveloped in these gases (as the spectroscope indicates to be the case in some of these flashing stars), would eject hydrocarbon vapors, condensible by cooling into solids similar to those we obtain by the condensation of terrestrial hydrocarbon vapors (paraffin, camphor, turpentine, and all the essential oils, for example), and thus we should have the meteoric systems composed of these particles circulating about their own common centre of mass as above stated, and displaying the spectrum which Dr. Huggins has found common to comets.

If this is correct, the present comet comes from a sun that contains metallic sodium in addition to the hydrocarbons, as the spectrum of this metal was seen when this comet was near enough to the sun to render its vapor incandescent.

FOOTNOTES

[1] Up to the present date (1882) nobody, as far as I know, has questioned my figures or defended those of Wollaston. Sir William Grove has written to me, pointing out his own anticipations of my conclusions respecting the universality of atmospheric matter. Sir Charles Lyell, before his death, expressed very strong approval of my conclusions, and many other men of scientific eminence have done the same. To expect any immediate, unreserved adoption of such bold speculations would be unreasonable.

[2] Since the above was written these analogies have been generally accepted.

[3] Since the publication of “The Fuel of the Sun,” Mr. Norman Lockyer has adopted this view of solar dissociation, and has gone so far as to suppose that it splits metals and other substances regarded by modern chemists as simple elements into more elementary and simple constituents. He assumes that the temperature of the solar atmosphere, growing higher at increasing depths, becomes somewhere capable of doing far greater dissociation work than that which separates the hydrogen of the prominences revealed by the spectroscope. In putting forth this “working hypothesis” he seems to have lost sight of the fact clearly proved by Deville’s experiments, that the temperature of dissociation rises with the pressure to which the compound is subjected, and thus that within the bowels of the sun the metals will be far less dissociable than they are on the surface of our earth.

[4] Still more recently (1882) the magnificent photographs of Jannsen have displayed further evidence of the flame-tongue character of the mottling.

[5] Subsequent observations (1882) by Secchi, Young, and others have demonstrated velocities far exceeding this; quite sufficient to project the solid matter clearly beyond the sphere of solar attraction.

[6] My first memorandum on this subject is dated April 23, 1840, in a _Register of Ideas_, then commenced in very early student days.

[7] Any reader of “The Fuel of the Sun” will perceive that the vaporous envelope which I have described as “an effectual jacket for limiting the amount of radiation,” is a complete theoretical anticipation and explanation of the “solar crust” of Respighi and the “Trennungschicht” of Zöllner. We agree perfectly in our conclusions, though arriving at them by such very different paths, and so independently of each other.

[8] What did he smell? Was it an emanation from the soles of my feet? If so, how did this aura get through the soles of my boots, which were thick? It could scarcely have been the odor of the boot soles themselves that he followed, as he recognized me afterwards at some distance. This suggests an interesting experiment, that anybody owning one of these dogs may easily try. Make a similar track to mine, but when on the way, take off the boots you wore on starting and change them for some one else’s boots, or a new pair, and watch the result from the window.

[9] “The Fuel of the Sun,” Chapters iv. to x.

[10] Since this was written some such modifications have been made with equivocal results.

[11] _Nature_, vol. xiv. p. 429.

[12] See Chapter on “The Origin of Lunar Volcanoes.”

[13] The burnt card, burnt bamboo, and other flimsy incandescent threads now (1882) in vogue, merely represent Starr’s preliminary failures prior to his adoption of the hard adamantine stick of retort-carbon, which I suppose will be duly re-invented, patented again, and form the basis of new Limited Companies, when the present have collapsed.

[14] Hull, “On the Coal-fields of Great Britain.”

[15] “The Great Ice Age, and its Relation to the Antiquity of Man.” By James Geikie, F.R.S., etc. Second edition, revised, 1877. Daldy and Isbister.

[16] The terminal moraine at the Oxfjord station, which I have already mentioned as the only ancient example of an ordinary moraine that I have seen in Arctic Norway, was, of course, a special object of interest to me. Further observation showed that it does not merely consist of the heap of stones I noticed in 1856, which appears like a disturbed talus cut through and heaped up at its lower part, but that there is another moraine adjoining it, or in continuation with it, which is covered with vegetation, and stretches quite across the mouth of the valley. The Duke of Roxburgh, who is well acquainted with this neighborhood, having spent sixteen summers in Arctic Norway, was one of our fellow-passengers, and told me that this moraine forms a barrier that dams up the waters of a considerable lake, abounding with remarkably fine char. I learned this just as the packet was starting, too late to go on shore even for a few minutes, and obtain a view of this lake and the valley beyond. This I regret, as it might have revealed some explanation of the exceptional nature of this moraine. It would be interesting to learn whether it belongs to the greater ice age, or to that period of minor glaciation that fashioned the farm patches already described. The formation of the lake is easily understood in the latter case. It is only required that such a minor reglaciated valley as one of these should be of larger magnitude and of very gentle inclination at its lower part, so that the secondary glacier should die out before reaching the present seashore. It would then deposit its moraine across the mouth of the valley, and this moraine would dam up the waters which such a valley must necessarily receive from the drainage of its hilly sides. Llyn Idwal, in North Wales, is a lake thus formed.

[17] See “Through Norway with a Knapsack,” chapters xi. and xii., for further descriptions of these.

[18] Lyell, “Elements of Geology,” p. 159.

[19] The celebrated “Maelström” is one of the currents that flow down the submarine incline between these islands when the tide is falling. Although I have ridiculed some of the accounts of this now innocent stream, I am not prepared to assert that it was always as mild as at present. If the ancient glaciers were stopped suddenly, as they may well have been, by the rocky barrier of Mosken, between Vaerö and Moskenesö, and they then suddenly concluded their deposition of till, a precipice must have been formed between this and the deep sea outside the islands, down which the sea would pitch when the tide was falling, and thus form some dangerous eddies. This cascade would gradually obliterate itself by wearing down the precipitous wall to an inclined plane such as at present exists, and down which the existing current flows.

[20] The largest of the Norwegian lakes, the Mjosen, is 1550 feet deep, and its surface 385 feet above the sea-level. Its bottom is about 1000 feet lower than the sea outside, or 500 to 800 feet below the bottom of the Christiana Fjord. The fjords, generally speaking, are very much shallower near their mouths than further inland, as though their depth had been determined by the thickness of the glaciers flowing down them, and the consequent limits of flotation and deposition.

[21] This has been recently overcome to a great extent by using glycerine instead of water.

[22] Since the above was written I have made some experiments with a solution of shellac in borax (obtained by long boiling), and hereby claim the invention of its application to this purpose, in order to prevent anybody from patenting it. I shall not do so myself.

[23] Written during the coal famine of 1872–73.

[24] From 1870 to 1880 the amount has risen from 110,431,192 to 146,818,622 tons per annum, an average increase of 3,638,743 tons per annum.

[25] At the present time (1882) we are receiving the excessive supplies consequent upon the opening of new pits that, under the stimulus of high prices, were in the course of sinking when the above was written. Hence the present low prices. Presently the annual increase of consumption will overtake this increased supply, and another “coal famine” like that then existing will follow. This is not far distant.

[26] “The Coal Fields of Great Britain,” pp. 447, 448.

[27] In a paper on the Comstock mines, read at the Pittsburg meeting of the American Institute of Mining Engineers in 1879, by Mr. John A. Church, the hot mine waters are described as reaching 158° Fahr. (so hot that men have been scalded to death by falling into them). The highest recorded _air temperature_ there is 128°. These are silver mines, and vigorously worked in spite of this temperature and great humidity. A much higher temperature is endurable in _dry air_.

[28] The scientific pedant of the Middle Ages displayed his profundity by continually quoting Aristotle and other “ancients.” His modern successor does the like by decorating his pages with displays of algebraical formulæ. In order to secure the proper respect of _my_ readers I here repeat the equation that I enunciated many years ago, “_c_ = _s_/_p_” where _c_ stands for civilization, _s_ for the quantity of soap consumed per annum, and _p_ the population of a given community.

[29] Geologists who may be interested in seeing the results of this experiment, will find on the Edgbaston Vestry Hall, in Enville Road, near the Five Ways, Birmingham, some columns, massive window pieces, doorways, and ornamental steps cast from the fused Rowley Rag and slowly cooled.

[30] In each of my three visits to America 1 lost about thirty pounds in weight, which I recovered within a few months of my return to the “home country” (of English-speaking nations).—RICHARD A. PROCTOR.

[31] Since the above was written, a correspondent in Paris tells me that a caricature exists, representing a Frenchman enjoying an open fire by standing on his head in the middle of the room.

[32] See foot-note, page 365.

[33] I tried the seeds given to me by Messrs. Carter, and find them to produce the same plant as my own, which I still cultivate very successfully. I now sow it in the spring as a kitchen garden border.

[34] Subsequent experiments induce me not to recommend this economy, on account of the bagging which results from excessive width between the frames; 3 feet should not be exceeded.

[35] I have followed up Mr. Trewby’s hint, and find that more than one quality of scrim is made. The best, made entirely of flax, costs rather more than the 2¼_d._ stated in the estimate, but it is the cheapest practically. The best I have seen is that used in the Houses of Parliament.

[36] Watt’s own figure for the latent heat of steam at 212° was 950°, but I adopt that which is now generally accepted.

Transcriber’s Notes

Punctuation and spelling were made consistent when a predominant preference was found in this book; otherwise they were not changed.

The original text contained many typographical errors. The simple ones were corrected without comment here; others are noted below.

Unbalanced quotation marks were corrected, as proper placement always could be determined.

Some typographical errors probably remain undetected.

Ambiguous hyphens at the ends of lines were retained; occurrences of inconsistent hyphenation have not been changed.

Text uses both “Acadamy” and “Academy”; both retained here.

Page 336: “The disagreeable sensation experienced by Dr. Siemens in the stove-heated railway cars, etc., were probably due to this” was printed that way. Either “sensation” should be “sensations” or “were” should be “was”.

End of Project Gutenberg's Science in Short Chapters, by W. Mattieu Williams