# Popular Science Monthly/Volume 36/March 1890/A Chemical Prologue

 A CHEMICAL PROLOGUE.
By C. HANFORD HENDERSON,

PROFESSOR OF PHYSICS AND CHEMISTRY IN THE PHILADELPHIA MANUAL TRAINING SCHOOL.

THE human infant, during the first few weeks of its life, must be regarded simply as a bundle of possibilities. A bright light, a loud noise, an appreciable degree of heat or of cold, produce, it is true, corresponding reactions. The child blinks, or it starts, or it shrinks, and there is manifest to the most careless observer a general sense of uneasiness. But these reactions must be regarded as purely involuntary. One can not discover in any of them the presence of thought. There is no co-ordination of the faculties. The touch includes anything that may come within reach. It does not act in any way in harmony with the eye. Nor does the gaze become fixed upon any object. The eye wanders from one thing to another without really seeing anything. Similarly with the sense of hearing. Sound is a mere vibration, without any meaning whatever. If it be sufficiently loud, it makes the infant start much as a violent explosion would shake a window or rattle a pile of dishes.

But as the weeks roll by, there comes a marked change. When the child reaches the age of three months the presence of will becomes unmistakable. The faculties begin to act in harmony with each other; or, as we are apt to say, the child begins to take notice. Then it is that the birth of the human soul into the little body becomes apparent. The child is observed to fix its gaze upon objects. It begins to recognize faces; it begins to see; it begins to hear; it begins to feel. In a word, intelligence has dawned.

The years succeeding infancy are full of incident. Each day is crowded with new experiences and new sensations. Years pass before the most obvious of these are exhausted of their interest. The child reaches out its hand for the moon; it finds delight in the glancing sunbeam; it is surprised by its own reflection in the glass; it is charmed by all forms of rapid motion; it dances gleefully before the fire; it is made curious by the rustling of a leaf. The little man is full of the spirit of investigation. He is a true experimenter. He is constantly putting questions to Nature, and, after a fashion, he is finding answers. He awakens to consciousness in a world that is for him full of wonders and surprises. There is no truer fairy-land than that in which he daily moves. The ever-present mystery; the delightful sense of anticipation; the persistent belief in the impossible, make childhood—in spite of its little worries and absurd fears—a veritable paradise, from which advancing years, like the angel with the flaming sword, casts us out all too soon.

The activity of the child is exceedingly interesting in the abstract; perhaps a little inconvenient in the concrete. He throws a goblet on the floor, and is as much amazed that it should break as the owner of the goblet is annoyed. It is a destructive age, and is apt to meet with but little sympathy from older persons who forget that they have gained their own store of knowledge from just such a series of adventures. Children willingly sacrifice a toy to learn what it is made of, and I am disposed to think that the knowledge so gained is worth more than the plaything. And so the first years of life are spent in becoming acquainted with surrounding objects. The days are very full of pleasure when one is acquiring knowledge in this simple and natural fashion. All of us have gone through these experiences. By hundreds of tests—pleasant and otherwise—we have learned that certain substances are brittle or tough; are hard or soft; are rigid or flexible; are light or heavy. By repeated falls we have gained some notion of gravitation—that bodies unsupported will fall to the ground. Burned fingers have taught us that flame and fire are hot. Torn jackets have shown us that there is a point beyond which we can not go and expect cloth to resist strains. It is in this way that we have gained our stock of common knowledge. Experience is undoubtedly the best teacher. When maturity is reached, all have gained the greater part of this common stock, and the affairs of everyday life proceed upon the very reasonable supposition that such knowledge may be taken for granted. But the question arises as to whether experience shall be permitted to end here, and so superficial a knowledge content us. It has been good for man to learn these more common truths. Would it not, then, be well for him to carry the search somewhat further, and to learn facts less commonly observed, as well as to investigate as far as he is able the cause and significance of all phenomena? There is but one answer: it is overwhelmingly affirmative.

It is to this problem that science addresses itself. The value of a study so intimately connected with the conduct of life is attracting an increasing number of students. The old battle between science and the classics in college curriculum does not need to be waged over again. Generations devoted to the pursuit of language have at length evolved a people in whom facility of expression is hereditary. The lack of something to say alone prevents universal authorship. The youth of the present day ask a discipline more inspiring than that offered by grammar and lexicon. It is found that the mind can be both instructed and trained without first killing the natural curiosity and interest of the pupil. It is true that there is a college near Philadelphia where a young woman is not even permitted to take a special course in biology unless she has an intimate knowledge of at least three foreign tongues, but happily such absurdities are rare. As a rule, the colleges and universities of the country have responded generously to the demand for broad scientific culture. In that field the battle has been won. But a little leaven leaveneth the whole. Beginning at the top of our educational system, the tendency toward scientific study is gradually making its way down to the very Kindergarten. It would be still more general, and would be a larger factor in individual life, were that important truth realized which Mr. Herbert Spencer has so often insisted upon, that scientific knowledge is simply a higher development of common knowledge, and means only more accurate and more extended thinking about our environment. And so, in science, we are to become again as little children, and put more questions to our great mother, Nature.

The results of this renewed questioning will not be trivial. They serve a dual purpose. They bring a much enlarged experience, and discover to us the relation between widely different phenomena. By the one service, the confines of our apprehended universe are expanded to such magnitudes that they demand for their occupancy the highest intellectual effort of which man is capable. Through the other, no confusion results from this immensity. It is a world of harmonies and relations. Man feels himself not oppressed, but inspired, by such a contemplation of Infinity. He is one both with that star-beam which left its home before America was discovered, and with the blowing flower which a breath of summer has called forth. It is no mean vantage -ground, nor one which the spectacled haunter of libraries can afford to despise, to feel one's self a sharer in the pulsating life of the universe, to be a citizen of space, at home everywhere. Such is the position of the earnest scientist. He is the true poet and the true prophet. He lives in communion with a God who is the same yesterday, to-day, and forever; in whom there is no variableness, neither shadow of turning. This absolute confidence in the inexorableness of divine law begets a serenity of life which is with difficulty disturbed, and a deep morality of thought and deed which is seldom the child of more local revelation. The idea of chance or caprice becomes impossible.

"All's love, but all's law."

It is with a curious pity that the student of Nature watches the crowd of worshipers at the Tower of Babel. He is willing to admit, with Max Müller, that there is no thought without language, and no language without thought; but so pre-eminent seems the thought to him that he feels well assured that a suitable vehicle will not be wanting for the carriage of so royal a guest. To such a one, the conduct of life becomes the chief end of education. The crucial test which he applies to each branch of study offered to either young or old is not whether it is useful, but whether it is the most useful. He will not be satisfied with any choice that is merely second best, for time meanwhile is flying, and, if we do this, we can not do that. The question is not whether any particular course will bring wealth of information, but rather whether it will induce fullness of living. It is surprising with what a small stock of facts, if they be of the right sort, a man can get along, and still be happy and progressive. I remember, as a boy, the envious regard which I bestowed upon a little friend of mine, whose dexterity in the difficult art of parsing quite surpassed my own feebler efforts. But one day I made the discovery that not only was he no better for entertaining that sort of knowledge, but, what was more surprising, his English was no more polished than my own. Since that time I have had frequent occasion to recall the discovery, and I confess that it has reconciled me to an ignorance upon many similar subjects. The substitution of this artificial, lifeless knowledge for that which is natural and organic, must be regarded as scarcely less than criminal by those who hold the true aim of culture to be the evolution of wisdom and of goodness. A man can not be expected to think soundly about a world of which he is quite ignorant, or to bring himself into relation with a universe whose confines are nearer than his finger-ends.

It is true that scientific education may fail quite as dismally as the classical has in times past if the grand generalizations of science are to be obscured by its manifold details. Emerson has somewhere said, "Men are so prone to mistake the means for the end that even natural history has its pedants who mistake classification for science." As a detached fact, the knowledge that water is composed of hydrogen and oxygen has no value. It is only when brought into relation with other chemical facts that it becomes significant. The statement found in elementary physical geographies and geologies that nine hundred and seventy-seven thousandths of the earth's crust consist of the nine elements—oxygen, silicon, aluminium, calcium, magnesium, sodium, potassium, iron, and carbon—carries very little instruction with it unless the children know the substances of which these names are the symbols. Mere classification is a weariness of the flesh. Science has no greater lesson to teach than roots and case endings have, unless it be linked to human life. Nor must it be pursued externally; it must touch our own experience, and its truths become a part of us, to be remembered because they can not be forgotten. This is knowledge, and nothing less than this deserves the name.

It is not so difficult to make even the more profound scientific studies touch intimately our daily life as one would imagine who has been taught to mistake classification for science. It is true that the multitude of objects which come within the field of scientific research require for their distinction a nomenclature which is not brief, but the student needs only a small part of it in the beginning. His vocabulary will grow with the using. In his "American Addresses" Prof. Huxley says, "For the purpose of getting a definite knowledge of what constitutes the leading modifications of animal and plant life, it is not needful to examine more than a comparatively small number of animals and plants." This, indeed, is the distinctive method of science. The student is made to advance from the particular to the general. The result justifies the method. By knowing a few things well, one knows everything, for one can not know even a few things well without having discovered by that very study the essential unity underlying all things. Our great geologists are not those who have "done" the earth, but rather those who have patiently and persistently studied a very small corner of it. To this rational mode of study all sciences are unmistakably coming. From its very nature, chemistry has been among the last to fall into line. It has been held, and in most quarters is still held, that the number of substances studied by the chemist should be limited only by the span of life. In accordance with this view, the young student, instead of being allowed to make friends with a few of the elements and really inquire into their secrets, lias been hurriedly introduced to all of those available, and has been left to struggle as best he could with their multitudinous compounds. The result has been to confuse, and in many cases finally to disgust. Chemistry—and I do not wonder at it—has been voted "dry" by the majority of college boys.

This result has come about because the science has been unscientific. The meaning of science is to know, but one knows very little from such a gallop among the varied forms of matter. If one knows thoroughly two or three typical gases, two or three typical liquids, and two or three typical solids, he knows chemistry. He may not be worth much as a reference-book; but then encyclopedias are nearly always available, while thoughtful men are rare. Further, the quality of such knowledge deserves attention. It has become a part of the man himself, for he has learned it the way children learn things. It is no longer simply a fact of chemistry; it is a fact of life, a part of the oft-repeated experiences which go to make up his intelligence. Imagine for a moment the amusement of a bright boy were he asked whether he remembered if stones are hard, or lead heavy, or glass brittle. His answer will be that of course he does not; he knows that they are. It is knowledge of a similar definiteness that the scientific method strives to cultivate. Studied in this way, chemistry ceases to be a matter of simple memory, and becomes almost exclusively a branch of pure reasoning. It passes from the objective to the subjective world, and becomes a valuable means of mental development as well as a study now well worth pursuing for its own sake.

One of the first requisites, then, in the proper presentation of chemistry seems to be the entire banishment of that alien element which makes it a thing by itself, and the insistence upon its recognition as a purely natural extension of common knowledge. Any experience in life will form a suitable starting-point. It may readily be analyzed into its components; the chemical element can not well be missed. If the occurrence be such as we commonly call accidental, or, more strictly speaking, if it be devoid of human agency, it will resolve itself into two terms, conveniently expressible by the words matter and motion. If the occurrence be voluntarily producible, a third element is involved—that of will. It would be foreign to the present purpose to enter the vexed discussion of whether this third element, this unknown something which makes the distinction between conscious and unconscious existence, is the cause or the result of those reactions in matter and force with which will, as we know it, seems to be indissolubly connected. It will be sufficient for the present to call it ${\displaystyle x}$, a designation involving neither issues nor compromises. Any common event, then, which may be selected by way of illustration, will furnish two elements open to scientific study—matter and motion. The distinction between the two is more convenient than essential, for we are unacquainted with matter devoid of motion, and the idea of motion divorced from matter is similarly unthinkable. However, the distinction is convenient, so that it will be well to follow it. The study of the analysis and synthesis of matter is the field of chemistry. The study of those varied motions which give to matter its apparent properties belongs to the domain of physics. The two sciences are commonly made the objects of separate study. It would be more true to nature to consider chemistry simply as a branch or subdivision of physics, for it is impossible to make any change in the constitution of matter without at the same time disturbing the physical equilibrium. Heat is either given out during the reaction or it is taken in. If it be chemical combination, heat is commonly disengaged; if a chemical disunion, heat is commonly involved. So general is the truth of this statement that we are able to predict what will occur chemically if the physical conditions are known. If there be two or more reactions possible, that one will take place which will liberate the greatest amount of heat. It is, indeed, the distinctive character of the so-called New Chemistry that it takes cognizance of the physical reaction which invariably accompanies the chemical. If the labors of Crookes, Roscoe, Hunt, and other eminent contemporary chemists count for anything, it is from such joint study as this that the best secrets of chemistry are to be evolved. With the view of lessening difficulties, this necessary interdependence between the chemical and physical is frequently omitted in presenting the science to young students; but the practice of teaching errors or half-truths, in order that the truth itself may afterward be apprehended, has as little excuse in science as it has in religion, for generally it is the error which proves obdurate, and the subsequent truth has no chance whatever. It robs the science, moreover, of an element of vitality which is one of its chief attractions.

In selecting our illustrations of chemical action, the more commonplace the event the better. The affairs of every-day life present such excellent objects for study that it would be as unnecessary as it would be uselessly distracting to go in search of the unusual, until the fundamental principles have been learned from a study of that which is familiar. That coal will burn, that milk will sour, that iron will rust, that cider will turn into vinegar, and that wood will decay, are all well-known facts of every-day life. But they are also facts of chemistry, for they involve a change in the composition of matter. It needs no scientist to perceive that the original coal, milk, iron, cider, and wood have disappeared as such, and that new substances with totally different properties have taken their place. Yet this is all that a chemical reaction means. It may be studied any day in the kitchen. The question of heat is quite as obvious. The coal has been burned for that very purpose. At first sight these several facts seem entirely unrelated. They have been selected quite at random. A moment's consideration, however, will show that these reactions, though seemingly dissimilar, are essentially identical. Your cook may not be able to explain them to you, but she can tell how they may be prevented, and that will serve the purpose equally well. Her answer will be the same for all: Keep the air from them. A fire with all the draught closed off goes out. Hermetically sealed milk keeps fresh. Painted iron does not rust. Bottled cider remains cider. Wood, not exposed to the air, will endure for centuries. So, after all, the common element in these reactions is not difficult to find. It is manifestly the air, for, in the absence of that, they do not occur. To the chemist they are all cases of oxidation. If he wishes to prevent them, he does just what the cook does—he keeps the oxygen of the air away from them. That is all that Mr. Edison does when he pumps the air out of the bulb of his incandescent electric light, so that the little carbon horseshoe shall not burn up.

Now, there is nothing occult about all this. The examples given are not sufficient in number to warrant any very broad generalization, but they can readily be extended, and conclusions of universal application reached without other resource than that found within one's self. Beginning in the home, one's conclusions will be found to extend to the town, to the county, to the State, to the world. One may finally think about the universe. The spirit in which these investigations are conducted will be that of an inquiring child. It is literally true in science that "a little child shall lead them." The men who have built it up have labored successfully in exact proportion as they have put their questions directly to Nature rather than to books and to the sages. The most hopeful sign that the growing scientific mind can disclose to its fellows is that increasing simplicity of heart and mind which has characterized all the immortals recognized by science. It is this very faculty that has made men of science so notoriously incompetent in business matters. We have come to expect little news from a sharp bargainer.

Questioning Nature in this childlike and natural fashion, life becomes again a daily revelation, and inspiration a contemporary event. It is paradise regained. There are still suffering and sorrow, but there are also their antidotes, hope and faith. There is universal law, but there is also universal love. The severe harmonies of the universe lend grandeur and dignity to the passing moment. One feels that the destiny of man is assuredly noble.

The student will not go far in his quest before facts begin to accumulate which are fraught with the deepest significance. He has known perfectly well all along that only a certain amount of heat can be obtained from burning a definite quantity of coal, and that it will be given out in proportion to the rapidity with which the burning is accomplished. If he wishes his room to be warmer, he opens the draught and gives a more abundant supply of air to the fire. The operation has been too often repeated to excite any wonder. But it becomes significant when he discovers that all other chemical reactions rest upon precisely the same principle. Each substance is found to have a definite combining power, and in every reaction, however simple or complex it may be, a definite quantity of one element unites with a definite quantity of another. If too much of either element be taken, it will be left over. But this is the law of definite proportions discovered by Dr. Dalton in the early part of the century and now the very corner-stone of chemical science. If the student further inquire what has become of the coal and the oxygen whose union we call combustion, he will find that a colorless gas, carbonic-acid gas, has been formed whose weight is exactly equal to the sum of their weights. Other illustrations will yield parallel results, and the far-reaching conclusion will be forced upon him that man is neither able to create matter nor to destroy it. This single truth once really apprehended gives a stability to thought which can scarcely come from any other single consideration. The universe is seen to be in an eternal ebb and flow, but its materials are seen to be constant. Once persuaded of the fact, and the suspicion arises that the same may be the case with heat and other forms of motion. And such he finds to be the truth. He learns that energy likewise is neither creatable nor destructible, and that all the work going on in the universe is simply that of transformation. New distributions of motion and new combinations in matter, these make up the cosmic life, but the sum total in each case remains unaltered. Perpetual motion is seen to be more than a possibility; it is found to be a necessity. One sees all of the universe in a state of ceaseless flux, sees that nothing stands still, that growth involves never-ending change, and becomes prepared to accept without fear those changes of opinion which intellectual growth necessitates as well as that great change of state which we call death. I can not hold as idle or of secondary import the speculations which these considerations engender. It is good for a man to penetrate as far as he may into the established order of the universe, for its secret is his secret, its process is his process. Curious thoughts spring from brooding over these doctrines of the conservation of force and matter. If in imagination we go back to that early time when our little planet was thrown off from its parent sun, we see, in the nebulous stuff from which it has precipitated, the materials of our own bodies. We are conscious of having had part in that wonderful birth, of having been present at the creation of the earth. It is true that we were very absent-minded at the time, but nevertheless our interest in that little ball of glowing vapor sent whirling off into space was even then a very personal one, for it was the aerial ship that carried our own destinies. If, then, the smallest atom that to-day forms a part of the delicate organism which we hold to be the tool of an indwelling spirit, has existed from all time, and is pledged to all eternity, it is difficult for the student of nature to conceive that the intellect which has given worth and dignity to this otherwise inanimate mass of matter should not be equally enduring. He is led to believe in an immortality of spirit which has known no beginning and will know no end. He is brought to what may be called the doctrine of the conservation of soul.

It has been a dream of poets and philosophers that there is in all the universe but one true element, and that the so-called elements—what we know as gold and silver, copper and iron, hydrogen and oxygen—are but modifications of this one primordial unit. The chemists of the nineteenth century are turning poets and dreaming this dream over again. What would have been scorned but a few years ago as alchemists' madness is now orthodox science. It is hard to believe that such a heavy, infusible metal as platinum has anything in common with a light, combustible gas like hydrogen; but, when we come to think about it, it is still harder to believe that the two are unrelated. When it is found that such dissimilar substances as charcoal, graphite, and diamond are chemically identical, it is quite possible to believe that all the elements are the products of a chemical evolution that has perhaps started with the element "helium," which the spectroscope discloses in the atmosphere of the sun. Thus the belief in the essential unity of the universe grows apace, and the cosmic drama gains in wonder as it gains in simplicity. What Goethe has called "the open secret of the universe" stares every man in the face. As one follows the wonderful story of its mode of becoming, and traces the far-reaching harmonies and relations, he is moved to exclaim with the devout Kepler, "O God, I think over again thy thoughts after thee!"

These considerations by the way, have for their sole purpose the indication of what I feel to be the rational mode of approach to the study of chemistry. It is a science so competent to become a means of keen intellectual pleasure and a stimulus to the most profound thinking, that its neglect by all but special students seems to me the neglect of a source of inspiration that one can ill afford to slight. Pursued in the spirit that I have tried to indicate, as a natural extension of the experimental knowledge of childhood, and through the medium of a few substances thoroughly studied, I venture to recommend it quite as highly as a means of culture, as an end valuable in itself. It would be an easy task to extend such considerations indefinitely; but I want rather to open the right door into chemistry, than to decorate its vestibule. "It is a foolish thing," says the author of the Book of Maccabees, "to make a long prologue and to be short in the story itself."