Part 16

Thus far nothing has been said about the composition of matter. A chemical process has been defined simply as certain factors yielding certain products, but nothing has been determined about the relations of these several substances except in so far as they are defined by the three laws illustrated above. But now it must be shown that a study of different chemical processes compels us to conclude that in some cases two or more substances unite to form a compound, while in other cases a compound is broken up into simpler parts. Thus, when copper-filings are heated in the air, it is evident that the material of the copper has united with that portion of the air we call oxygen to form the black product we call oxide of copper; and again, when oxide of silver is heated, it is evident that the resulting silver and oxygen gas were formerly portions of the material of the oxide. So, when water is decomposed by electricity, the conditions of the experiment show that the resulting oxygen and hydrogen gases must have come from the material of the water, and could have come from nothing else.

Experiments should now be multiplied until the student has a perfectly clear idea of the nature of the evidence on which our knowledge of the composition of bodies depends. The decomposition of chlorate of potash by heat, yielding chloride of potassium and oxygen gas; the decomposition of nitrate of ammonium by heat, yielding nitrous oxide and water; the decomposition of this resulting nitrous oxide, when the gas is passed over heated metallic copper; and, lastly, the decomposition already referred to, of water by electricity--are all striking experiments by which the evidence of chemical composition may be enforced.

The distinction between elementary and compound substances having been clearly defined by the course of reasoning already given in outline, the next aim should be to lead the student to comprehend how substances are analyzed and their composition expressed in percents. The reduction of oxide of copper by hydrogen gives readily the data for determining the composition of water, which is thus shown to contain in one hundred parts 11·11 per cent of hydrogen and 88·89 per cent of oxygen.

Another substance whose analysis can be very readily made by the student is carbonate of magnesia. By igniting pure carbonate of magnesia in a crucible (not of course the "magnesia alba" of the shops), the proportions of carbonic acid and magnesia can be readily determined. Then, by burning magnesium ribbon, and weighing the product, the student easily finds the relative weight of magnesium and oxygen in the oxide. And, lastly, the proportion of carbon and oxygen in carbonic dioxide is easily deduced from the burning of a weighed amount of carbon. Here the result may be expressed either in percents of oxide or magnesium and carbonic dioxide, or else in percents of the elementary substances, carbon, magnesium, and oxygen.

After making a few analyses like these, the student will be prepared to comprehend the actual position of the science. All known substances have been analyzed, and the results tabulated, so that it is unnecessary to repeat the work except in special cases.

The teacher is now prepared to take a very important step in the development of the subject. If the molecule is simply a small particle of a substance in which the qualities of the substance inhere, then it follows, of course, that the composition of the molecule is the same as the composition of the substance. The percentage results of the analysis of water, or of carbonate of magnesia, indicate the composition of a molecule of water or a molecule of carbonate of magnesia. Thus, 11·11 per cent of every molecule of water consists of hydrogen, while 88·89 per cent consists of oxygen. Hence it follows that, in a chemical process, the molecules must be divided, and these elementary parts of molecules which analysis reveals are the atoms of chemistry. Moreover, as we know the weights of molecules, both by physical and chemical means, chemical analysis now gives us the weights of the atoms. We have no time to dwell on the details of this reasoning, but the general course to be followed will be evident, and it must be enforced by numerous examples.

Assuming that the student fully comprehends the distinction between molecules and atoms--that is, between the physically smallest particles and the chemically smallest particles--he is prepared to master the symbolical nomenclature of chemistry, with a very few words of explanation. The initial letters of the Latin names are selected to represent the atoms of the seventy known elementary substances, and these letters stand for the definite atomic weights which are tabulated in all chemical text-books. The symbols of the atoms are simply grouped together to form the symbols of the molecules of the various substances; the number of atoms of each kind entering into the composition of the molecule being indicated by a subscript numeral. Lastly, in order to represent chemical processes, the symbols of the molecules of the factors are written on one side and the symbols of the molecules of the products are written on the other side of an equation, the number of molecules of each substance involved being indicated by numerical coefficients.

The atomic symbols, as we have seen, stand for definite weights. In the same way, the molecular symbols stand for definite weights, which are the sums of the weights of the atoms of which each consists, and in every chemical equation the weights of the molecules represented on one side must necessarily equal the weights of the molecules represented on the other. The chemical process consists merely in the breaking up of certain molecules, and the rearrangement of the same constituent atoms to form new molecules. Again, as the molecular symbols represent definite weights, the equation also indicates that a definite proportion by weight is preserved between the several factors and products of the process represented.

Again, since every molecular symbol represents the same volume when the substance is in an aëriform condition, it follows that the relative gas volumes are proportional to the number of molecules of the aëriform substances involved in the reaction. Thus it is that these chemical equations or reactions are a constant declaration of the three great fundamental laws of chemistry.

In order to enforce the above principles, a great number of examples should now be given which should be so selected as to illustrate familiar and important chemical processes, including the all-important phenomena of combustion. In each case, the student, having made the experiment, should write the equation or reaction which represents the process, and should be made to solve a sufficient number of stochio-metrical problems, involving both weights and volumes, to give him a complete mastery of the subject. Such questions as these will test the completeness of his knowledge:

Why is the symbol of water H_{2}O? What information does the symbol CO_{2} give in regard to carbonic-dioxide gas? Write the reaction of hydrochloric acid on sodic carbonate, and state what information the equation gives in regard to the process which it represents.

Of course, such questions may be greatly multiplied, and I cite these three only to call attention to the features of the method of instruction I have been endeavoring to illustrate.

But, besides teaching the general principles of chemical science, it is important to give the student a more or less extended knowledge of chemical facts and processes--especially such as play an important part in daily life, or in the arts--and such knowledge can readily be given in this connection. Beyond this I do not deem it desirable to go in an elementary course of instruction. The way, however, is now opened to the most advanced fields of the science. A comparison of symbols and reactions leads at once to the doctrine of quantivalence, and to the results of modern structural chemistry which this doctrine involves. Among these results there is of course much that is fanciful, but there is also a very large substratum of established truth; and if the student thoroughly comprehends the symbolical language of chemistry, and understands the facts it actually represents, he will be able to realize, so far as is now possible, the truths which underlie the conventional forms.

The study of the structure of molecules naturally leads to the study of their stability, and of the conditions which determine chemical changes, and thus opens the recently explored field of thermo-chemistry. To be able to predict the order and results of possible conditions of association of materials, or of chemical changes under all circumstances, is now the highest aim of our science, and we have already made very considerable progress toward this end.

But I have detained you too long, and I must refer to the "New Chemistry" for a fuller exposition of this subject. My object has been gained if I have been able to make clear to you that it is possible to present the science of chemistry as a systematic body of truths independent of the mass of details with which the science is usually encumbered, and make the study a most valuable means of training the power of inductive reasoning, and thus securing the great end of scientific culture.

XII.

"NOBLESSE OBLIGE."

In the former essays of this volume I have earnestly maintained that scientific culture, rightly understood, is a suitable basis for a liberal education; and I have maintained this thesis without in any way attempting to disparage that literary culture hitherto so generally regarded as the only basis on which the liberal arts could be built. While, however, I have argued that, in the present condition of the world, there is more than one basis of true scholarship, I have fully admitted that for far the larger number of scholars, including all those whose lives are to be occupied with literary pursuits, the old system of education is still the best. Moreover, I have endeavored to point out that scientific culture in no way conflicts with literary culture; that it has a different spirit, a different method, and a different aim; and I have only recommended it as suitable to those who are distinctly preparing themselves for a scientific calling; but I have maintained that for such men scientific studies, rightly followed, may lead to a broad, a noble, and in the truest sense a liberal education.

I have used the term scientific culture _rightly understood_ in order to mark a distinction; because a great deal that passes for scientific scholarship in the world does not imply true scientific culture. In all departments of learning, and not less in scientific than in literary studies, erudition does not necessarily imply a high degree of culture. We all value the labors of the lexicographer, and the work may be so done as to task the noblest intellectual power; but there is a higher form of literary culture than that which dictionary-making usually implies. So also in science, no amount of book-learning constitutes what we have called scientific culture rightly understood. For example, the ability to pass an examination on the facts and principles of science is no test whatever of the form of culture we are advocating. Not that we underrate the value of such tests, or of the knowledge they imply; but the ability to master a subject as presented in a text-book, and to state that knowledge in a concise and accurate form, is the normal result of literary, not of scientific culture. The power to do something well is involved in the very idea of culture, and the scholar who can pass a successful written examination has acquired a power which literary culture chiefly gives, and that this power may be applied to scientific as well as literary subjects is obvious. Here is a most important distinction in connection with our subject. Culture implies the acquisition of some power of the mind in an eminent degree, and such power is constantly associated with erudition, simply because it leads to erudition. But when we see erudition without such power, as we often do in every department of scholarship, we perceive at once upon how much lower a level it stands. What very different things are classical scholarship and classical erudition; and is not the power which the great classical scholars possess of interpreting the thoughts of the classical authors, and of reproducing their life, the great element of difference between the two?

So scientific culture implies the ability to interpret Nature, to observe her phenomena, and to investigate her laws. The scholar, to whom Nature presents merely an orderly succession of facts and phenomena, knows nothing of true scientific culture. As there is a spirit in the great writers of classical antiquity which ennobles the study of the forms in which the thoughts of these authors were expressed, so also is there a spirit in Nature without which facts and phenomena, however well classified, create no intellectual elevation. The last century of the world's history has been marked, more than by anything else, by the increase of our knowledge of Nature, and it will be known in history as the age of great discoveries; but valuable as the facts and principles of science certainly are, greatly as they have promoted the well-being of mankind, and important, therefore, as the knowledge of these facts and principles must be to man, yet nevertheless I should never urge the claims of physical science as a basis of liberal education if they could be defended on no other grounds than these. It is here as elsewhere "the spirit which giveth life"; and the power to interpret Nature, and to commune with the intelligence that rules the universe, is the one acquisition which, above all others, gives worth and dignity to the form of culture we have endeavored to advocate in these essays.

Those who regard science simply as utilitarianism, and who value scientific studies solely because they teach men how to build railroads, to explore mines, to extract the useful metals from their ores, or to increase the yield of agriculture, have an even more imperfect conception of what is meant by scientific culture than those to whom science is merely a valuable erudition. It is true that physics and chemistry may be studied as arts rather than as sciences, and we have no desire to underrate the importance of such technical education; but the difference between the two modes of study is as wide as the difference between the artisan and the scholar. In asserting this we do not forget that the occupations of the engineer, the electrician, and the analytical chemist demand a very large amount of knowledge, judgment, and skill, and are rightly regarded as learned professions. But let it not be supposed that skill in such professions is the end or aim of scientific culture; any more than legal skill is the end or aim of literary culture. If literary scholars regard the study of science solely from this point of view, it is no wonder that they think that the tone of scholarship would be lowered if it rested solely on such a utilitarian basis; and, on the other hand, if they could once realize the sublimity of Nature, as Copernicus, Newton, Faraday, and unnumbered others have realized it, this fear that devotion to science must degrade scholarship would disappear.

We are well aware that practical men frequently regard with undisguised contempt the students of theoretical science, and that the greater number of persons seeking a scientific education must look for employment to the practical professions in which this tone too often prevails. But, certainly, a narrow technical spirit prevails quite as often in the professions in which literary scholars chiefly find employment; and the new scientific professions are even more closely dependent on the discussion of theoretical and abstract principles than those which have hitherto been exclusively regarded as liberal. It is an admitted fact, as we have shown in another place, that all the great advances in practical science, all the great inventions, which during the last century have so wonderfully increased the power of man over Nature, may be traced directly to the results of theoretical study. For this reason, if on no higher ground, we have claimed that it is both the interest and the duty of the State to foster and reward scientific investigation. The time is not far distant, if it is not already at hand, when the scientific culture of a people will be one of the chief factors in determining its position among the nations of the world.

We can not leave this subject without giving prominence to another thought, which has been ever present with us while writing these pages, if not hitherto distinctly stated. Culture, as we have seen, implies power, and the possession of power also involves corresponding obligations. Among the many blessings which Christianity and its attendant civilization have brought to mankind, the recognition of this principle is most plainly marked. The principle is assumed in almost every relation of life, even when not distinctly acknowledged; and happily it can rarely now be disregarded without incurring the odium of mankind. It leads the possessors of great wealth to devote no inconsiderable share of their fortunes to the public good; it stigmatizes as miserly any neglect of this obligation; and the best hope of preserving our modern civilization against the destructive agencies of socialism is to be found in the increasing recognition and enforcement of this saving grace.

But while this principle is, to a greater or less degree, acted upon in all relations of life, it is enforced by public opinion with special strictness upon those who assume to be the servants of the people. In political life the obligations it imposes are already very generally recognized; and still more strongly are they felt by the ministers of religion. The politician who uses his high position to promote his personal interests may sometimes escape his just deserts; but the clergyman who prostitutes his influence for private gains is universally condemned. So true is this, that a clergyman is debarred by his profession from many of the industries and occupations of life which are regarded as perfectly honorable callings for other men. A clergyman who speculated in stocks, or even engaged in a mercantile pursuit, would, with good reason, lose the respect of the very men who had gained their wealth by the same ways which they deny to him. He may not, like the members of the elder religious fraternities, take the vow of poverty, but still he is held to a very strict rule of life; and on this is based his claim to an adequate support from the people to whom he ministers. Because "appointed to sow spiritual things," the clergy are entitled "to reap worldly things" which they have not sown nor gathered; and evil will be the days when this claim is disallowed.

Now, we hold that the profession of a scientific teacher implies an obligation not less binding than that which rests on the clergyman; and this is especially true if the teacher has been placed in a conspicuous and responsible position before the world. The teacher has been set apart as truly as the clergyman, and, if he uses the influence of his office merely as a means of accumulating wealth, he is not loyal to the profession which he has voluntarily assumed. Let me not be misunderstood. There are a thousand legitimate ways of earning a livelihood and acquiring wealth by means of the knowledge which scientific study gives; and a man has a right to use scientific knowledge for his worldly advancement as freely as any other knowledge. But the man who has accepted the post of a teacher, and receives the support to which his position entitles him, is bound to do the work of a teacher to the best of his ability, and to devote his whole energies to extending the knowledge of the science which he professes to teach. It is of the utmost importance that the community should be educated up to this point, and should hold its teachers to their trusts and obligations as strictly as it does its clergy. Indeed, the scientific even more than the religious teacher requires the aid of a correct public sentiment to maintain the tone of his profession. Scientific knowledge and acumen, when centered on business relations, has often discovered direct avenues to wealth; the temptation to make use of the opportunities thus offered is of course very great, and in most of the relations of life the career so opened may be perfectly legitimate and honorable. But no one can expect to succeed in any business career without devoting his whole energy to the work, and there are conditions under which such a course would involve the betrayal of a trust. Nor are the words betrayal of a trust too strong; for it is sometimes the case that, besides neglecting his appropriate work, the scientific teacher sells the reputation of his position, and commands a higher price because he barters the good name of the institution with which he is connected.

I am well aware that there is another side to this question. In many of our colleges the professor has an inadequate support, and is expected or even invited to supplement his income by what is technically called "commercial work." Of course, in such cases the man can not be blamed; but public opinion should be such as to prevent a respectable institution from offering, or a respectable professor from accepting, such a position. The workman is worthy of his hire, and the same sentiment which demands from the scientific professor a whole-hearted devotion to his work, demands also from the community for which he works an adequate support.

It is undoubtedly in consequence of the inadequate support which scientific teachers generally receive in this country that public sentiment tolerates with them practices which sober judgment must condemn; and it must be remembered that under these circumstances a teacher, if he is faithful to the routine of his office, may devote his remaining energies to commercial work, not only without any consciousness of wrong-doing, but even with the approbation of his associates. Hence, it is the more important to establish firmly in the public mind the well-founded opinion that the endowed professorships of our higher institutions of learning are offices of public trust, to be administered solely for the public good. There is no hardship in this position; since perfectly legitimate and honorable avenues are opened to the scientific scholar, on which he may expend his business energies, and, at the same time, use his scientific knowledge; and for many men these avenues lead in the directions in which they can not only most effectually advance themselves in worldly prosperity, but also most benefit their fellows. Among the men of practical ability who have developed a new industry, or introduced a new invention, and who have acquired wealth thereby, are to be found some of the greatest benefactors of their race; and far would it be from me to institute a comparison between the practical men and the scholars. All we claim is that the men of affairs should resign the endowments intended for the maintenance of scholars to those whose zeal is sufficient to induce them to make gladly the sacrifices which the advancement of knowledge usually entails.