Popular Science Monthly/Volume 15/July 1879/Editor's Table



THERE is a certain class of minds whose efforts to explain things generally leave them more obscure than they were before. In undertaking to represent a question they complicate rather than simplify it, and instead of helping the learner to understand a subject they hinder him. This failure to make things lucid and comprehensible is due to various causes. Oftenest, it comes from a total neglect of the art of luminous writing, and it is unfortunate that many scientific men are not a little perverse about cultivating this art. They do not, as a matter of conscience, make any effort to enter into the state of mind of the parties addressed, and their expositions, therefore, often fail from lack of adaptation. Sometimes a subject familiar to teachers of great capacity is still too abstruse to be grasped by common minds. Sometimes the expounder does not understand the subject himself; and not unfrequently hypotheses are invented to explain unexplainable things, and which serve only to increase existing difficulties. A marked illustration of this is afforded by a lecture delivered not long ago before the Royal Institution, by the eminent physicist and mathematician, Sir William Thomson, who announced as his topic of discourse the curious subject, "Maxwell's Sorting Demons."

The lecture was mainly devoted to an explication of the phenomena of the diffusion of liquids and the principles it involves. Professor Thomson bad many tubes prepared, each containing two liquids of different colors, to represent the progress of diffusion, while some ingenious experiments were made by throwing the spectra of various solutions upon the screen with an electric light. The diffusibility of solids and gases was also referred to, and a just tribute paid to the memory of Graham, whose name stands most prominently associated with this branch of research.

Sir William Thomson's reasons, however, for bringing forward these phenomena of diffusion were that they stand very closely related to the present theories and speculations concerning the molecules of matter, and which aim to account for their motions. In diffusion, the molecules gradually intermingle, according to definite laws, which are variable in different cases. The molecules do not move capriciously or irregularly, as all chemical action and all crystallization prove. But why do they move this way or that, and why always go the same way in the same conditions? This "why" is the perplexing word of science, and when we get down among objects the very existence of which is hypothetical it carries us far beyond our depth. But Professor Maxwell thinks he gives us aid here by inventing a host of little demons—living creatures with wills and infallible intelligence—which sort the molecules and regulate their extraordinary motions. In a very brief abstract of his lecture which Sir William Thomson has published, he thus explains the attributes and offices of these remarkable agents:

Clerk Maxwell's "demon" is a creature of imagination having certain perfectly well-defined powers of action, purely mechanical in their character, invented to help us to understand the "dissipation of energy" in nature. He is a being with no preternatural qualities, and differs from real living animals only in extreme smallness and agility. He can at pleasure stop, or strike, or push, or pull any single atom of matter, and so moderate its natural course of motion. Endowed ideally with arms and hands and fingers—two hands and ten fingers suffice—he can do as much for atoms as a piano-forte player can do for the keys of the piano—just a little more, he can push or pull each atom in any direction.

He can not create or annul energy; but, just as a living animal does, he can store up limited quantities of energy, and reproduce them at will. By operating selectively on individual atoms he can reverse the natural dissipation of energy, can cause one half of a closed jar of air, or of a bar of iron, to become glowingly hot and the other ice cold; can direct the energy of the moving molecules of a basin of water to throw the water up to a height and leave it there proportionately cooled (1° Fahr. for seven hundred and seventy-two feet of ascent): can "sort" the molecules in a solution of salt or in a mixture of two gases, so as to reverse the natural process of diffusion, and produce concentration of the solution in one portion of the water, leaving pure water in the remainder of the space occupied; or in the other case, separate the gases into different parts of the containing vessel.

The classification, according to which the ideal demon is to sort them, may he according to the essential character of the atom: for instance, all atoms of hydrogen to be let go to the left, or stopped from crossing to the right, across an ideal boundary; or it may be according to the velocity each atom chances to have when it approaches the boundary: if greater than a certain stated amount, it is to go the right; if less, to the left. This latter rule of assortment, carried into execution by the demon, disequalizes temperature, and undoes the natural diffusion of heat; the former undoes the natural diffusion of matter.

This looks to us like a somewhat ridiculous way of evading the real difficulties in the explanation of molecular motions and their effects. All nature is supposed to be filled with infinite swarms of absurd little microscopic imps, which are so omniscient that they direct the invisible and insensible movements by which the whole order of nature is determined and maintained. When men like Maxwell, of Cambridge, and Thomson, of Glasgow, lend their sanction to such a crude hypothetical fancy as that of little devils knocking and kicking the atoms this way and that, in order to explain the observed changes of natural phenomena, we may well ask, What next? This is a palpable case of contriving an artifice to explain a subject which yet leaves the subject more obscure than ever. There were difficulties enough with the molecules considered alone, but when complicated with another hypothetical order of beings the difficulties are redoubled, for we have now to explain the explanation. There is a great proneness to invent explanations which only remove the trouble one step further away. Sir William Thomson's hypothesis of the origin of terrestrial life by means of germs, brought to our planet from some unknown source by meteorites, is another example of explanations by assumptions, in which nothing is explained. There is a class of scientific men who feel it incumbent upon them to answer all questions. They do not seem to appreciate the fact that there are limits to our knowing, which had better be honestly acknowledged, instead of offering conjectures which are mere travesties of legitimate theory, and absurdities in science.


We print an indignant letter from Mr. Bergh the philanthropist, denouncing one of our eminent ornithologists for saying that the English sparrows among us are interlopers, and, instead of being protected, should be left to shift for themselves, and be exposed to the raids of the street boys. We have a very high respect for Mr. Bergh and his mission, and have never been disposed to criticise his peculiarities or find fault with the way in which he has chosen to perform his duty. It is enough that such a man was greatly needed in the community, and it is not well to raise questions of taste, or to carp at mistakes committed in the performance of a disagreeable but most beneficent public service. We cordially approve of his practical work in protecting animals against the infliction of cruelty, whether from wantonness, carelessness, or insensate stupidity. But because Mr. Bergh's labors are important they ought to be maintained on proper grounds; though, judging from his letter, we should rather trust his instincts than his logic.

As regards the sparrows, Mr. Bergh seems not to recognize that they are at present under indictment, and, while we have no disposition to prejudge their case, it certainly is not to be settled on purely sentimental grounds. The question of their treatment depends upon whether or not they have become pests and nuisances. If it is true, as maintained by reputable naturalists and those who have observed their habits and history, that these birds are extremely prolific, hatching out several broods in the same season, and that, besides this, they have been so coddled and cared for as greatly to increase the usual rate of their multiplication; if it is true that they are quarrelsome and pugnacious little creatures, and by their bad dispositions and excessive numbers are driving out other birds, and consuming the means of subsistence, which all should share, and, moreover, if they are specially destructive to buds, fruits, and grains, as is also alleged, so that on the whole they may do a great deal more mischief than good—then it is just as proper to destroy them as to destroy any other pests. If such is their character, protection should be withdrawn from them, and they should be exterminated in all suitable ways. Mr. Bergh ought to have addressed himself to these considerations, and shown if he can that the charges against the sparrows are false, and that they are entitled to all the favors they get.

But he puts the case on different grounds. He objects to the killing of his pets for teleological reasons—that is, because it thwarts the purposes of Divine Beneficence, and, by the prominence he gives to this notion in his letter, we must assume that he regards it as imperative. He looks upon Dr. Coues as a man who would exterminate one of the "pretty little creatures of the Almighty," and that he is therefore an "enemy of God"; and Mr. Bergh expresses a somewhat sanguinary wish that he could get hold of him, and subject him to the guillotine of New York law.

Now, there is something wrong here. Whenever one party wants to give another party the law in the name of God, the matter requires looking into. Mr. Bergh assumes to know the Divine intentions: does he probably understand much more about them than his neighbors? He seems somewhat reckless in his mental movements, but is he not aware that the water hereabouts is very deep? He plays off theology upon Dr. Coues, but we suspect that the naturalist might give the philanthropist large odds, and still beat him at the game.

For when Mr. Bergh says to Dr. Coues, "You would let loose the street boys upon the sparrows, and are therefore an enemy of God," Dr. Coues may reply: "How do you know that the propensities of boys are not among the divinely appointed means of dealing with sparrows? And if it is a question of Divine purposes, who created the sparrow-hawk—the most destructive little savage ever set free in the sky? If you wish some pointed information regarding the intentions of the Almighty in respect to the treatment of sparrows, consult the excellent volume on birds by the Rev. J. G. Wood, page 85."

Should Mr. Bergh see fit to comply with the suggestion, he will there find that sparrow-hawks for some purpose have been provided on a very large scale, being plentifully found in all quarters of the world. That it may do its work of destruction effectually, the sparrow-hawk was made one of the most vicious, sanguinary, and cruel of all birds of prey. Usually very wild, shy, and wary, it is difficult of approach, except when "hovering about a flock of sparrows," and then "the ardor of its destructive propensities is so great that all its faculties seem to be absorbed in the gratification of the ruling passion, so that it is evidently unmindful of anything but its flying prey. A sparrow-hawk has even been known to dash furiously at a man, who endeavored to rescue a small bird which it attacked."

Hawks, as is generally known, are capable of being domesticated and trained to hunt as in the art of falconry; but the sparrow-hawk is so fierce and untamable that it is the worst of all its tribe for this purpose. It is indeed courageous, and will dash at any quarry that may be pointed out to it, but it is crabbed, intractable, and so treacherous that it can not be trusted. Besides, it "is so quarrelsome that if several of these birds should be fastened to the same perch or placed in the same cage they will certainly fight each other, and in all probability the conqueror will eat his vanquished foe! Such an event has actually occurred, the victrix—for it was a female—killing and devouring her intended spouse." A naturalist, writing in the "Field" newspaper, gives a very interesting account of the proceedings of "this handsome little hawk," showing it to be a most vicious wretch, and thus sums up its character: "The sparrow-hawk is, in my opinion, the wildest, in some sense the most intractable, the most ungrateful, the most provoking and temper-trying of all birds or beasts that ever were taken under the care of man from the beginning of the world."

"Now," Dr. Coues might say to Mr. Bergh, "if it be true, as Professor Agassiz always maintained, that animals are but embodiments of Divine ideas, we must consider this hawk, with its destructive weapons and murderous instincts, as representing the Divine conception of the sort of discipline to which sparrows should be subjected. It is divinely designed that their numbers should be kept down, so that other birds may have a chance. You thwart the Divine intention by artificially fostering them, and bringing about an unnatural state of things that is injurious. I would leave them to the Creator's universal and fundamental law of natural selection, which is a safer guide than blind, impulsive philanthropy, and I merely included street boys, with hawks, parasites, and a thousand other destructive agencies as the means of preserving the great balance among the orders of life."

The difficulty with Mr. Bergh is, that he puts behind his philanthropy, and as an impelling motive to it, an erroneous view of nature. The doctrine of Divine designs is a dangerous one to handle, because it cuts both ways, and proves too much. If the beneficent indications in nature are to be accounted for on the hypothesis of "intentions," so must the maleficent indications, and how are we to escape from the conclusion that cruelty also is designed? If we should say that the world was constructed and is administered on the principle of the "prevention of cruelty to animals," would it be quite true? Are not the means and appliances of destructive cruelty universal, and, if "intended" at all, were they not intended for their cruel uses? It would require an extensive museum to show us all the exquisite contrivances with which living creatures have been furnished to torment and kill each other. They were not made each with a gland to secrete chloroform that might be used in producing painless death. But, in place of any such kindly contrivance, there are claws, talons, beaks, tusks, fangs, hooks, saws, blades, stings, and malignant poisons in infinite variety of modification and adaptation for crushing, rending, tearing, lacerating, and torturing living and sensitive creatures; and these grim implements are furnished to all the grades of animate beings on the earth, in the sea, and in the air, from microscopic infusoria to colossal beasts that range the forests. Nor is this all: the creatures that are armed with these weapons of destruction are animated by the deadliest instincts to use them; in fact, they are driven to it by the very law of self-preservation. "Kill, that you may live," is the mandate of universal necessity.

But the roots of all this pitiless carnage strike still deeper into the method of nature. Life is wasted through these sanguinary devices with an infinite prodigality. Sensitive organisms to be sacrificed by suffering seem to be the cheapest things in the universe. The amount of inanimate matter is limited; but creatures formed out of it, and capable of pain, are boundlessly unlimited. Space restricts the material, but living organisms are multiplied forever in time. Destruction but makes room for more destruction; and not only is the onflowing river of life full to its banks, but ten thousand-fold more creatures are born than can be preserved. Each species reproduces at a rate that is out of all relation to the possible means of subsistence. If Mr. Bergh's sparrows could multiply at their normal rate, unchecked by the agencies of decimation, they would take possession of the world, and humanity and philanthropy would end together. And so it has ever been through the countless ages of the earth's history; so that its very rocks, for miles in depth, are filled with the fossil remains of innumerable tribes of creatures, which warred with each other through geological periods, and have now utterly perished. And it is to-day as it has been through the immeasurable past-millions of species scattered over the earth's surface, from pole to pole, are engaged in a struggle for existence, that is carried on everywhere with unrelenting severity.

From the point of view of sentiment alone, this is not a pleasant picture. Considered by itself, a hawk with a sparrow in its talons is not suggestive of beneficent intentions. If all this remorseless destruction has been beneficently designed, we must widen our notions of beneficent design. Science does this, by showing that out of the universal agony Nature is slowly, very slowly, working up to a better condition of things. In the sanguinary struggle the fittest survive, the ill-adapted and less perfect are slain, and there comes improvement. The value of this progress is to be estimated by its terrible cost. Through the destruction of tribes with what seems an almost infinite wantonness have finally come creatures with higher capacities of enjoyment, as well as correlative suffering, and an order of beings that have acquired great power over the conditions of pleasure and pain. In man, the last term of advancement in the animate series, ameliorations and modifications of his primal savage propensities have gone on, until there has grown up a set of feelings that are kindly, merciful, sympathetic, and benevolent; and they have at length become so strengthened and organized in our nature that they are characterized as "the humane sentiments," or the "spirit of humanity." These are the final product of man's moral evolution, and, although the reminiscences and survivals of savagery in the shape of military systems still linger, yet the kindly, merciful, and generous emotions are steadily gathering force in the hearts of men, and are becoming more and more the predominant law of the social state. Terrestrial life has had a tragic history, but, when under the stern discipline of a mortal competitive strife the primitive cannibals have been so utterly transformed that many of their descendants have come to find their highest pleasure in the gratification of the sympathetic feelings, and even to regard the brute creation with a tender solicitude, as evinced by the organization of societies for the prevention of cruelty to animals, who shall say that the grandeur of the end does not justify all the terrible means by which it has been attained?