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imitation. We must therefore look upon Johnson's poem as an imitation in form, but not in spirit. We might almost say that Juvenal's poem is a parody of Johnson's. As far as form is concerned Johnson is equal to Juvenal, and at times superior. Juvenal is not so careful about the connection of part to part. For often the wealth of his illustration leads him into disproportion, as is the case with his diatribe against old age. Johnson has, however, elaborated his theme very carefully,and as a result we have a poem almost as finished in style as are those of Pope. But outside of this form and a certain dignity of expression, a dignity which in Juvenal is often a mere mockery, the likeness ceases between the Latin and the English poem. And, so, as a truthful imitation, The Vanity of Human Wishes is a failure. It is rather, therefore, to be looked upon as an original production, stamped with an individuality, which, if it does not gain our admiration, at least commands our sincere respect.

CONFERENCE OF PHYSICS AND CHEMISTRY

EQUIVALENT WEIGHT OF MAGNESIUM

MR. E. A. CLEMANS, CENTRAL HIGH SCHOOL, DETROIT

This experiment is not given with an idea that it contains anything new or novel, but because it is simple and successful.

A piece of magnesium ribbon 1 meter long is weighed and cut into lengths of 4 cms. each. This is done by the teacher. The pupil fills

a 6-inch test tube with water at room temperature and inverts it in an evaporating dish partially filled. One of the small pieces of magnesium, whose weight is now known, is coiled about a rubber band and put under the test tube, the edge of the tube resting upon the rubber band and thus preventing the effervescence of hydrogen from carrying the magnesium into the upper part of the tube (Fig. 1). A few drops of sulphuric acid are poured into the evaporating dish and the hydrogen produced is collected in the tube. After the metal

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Fig 1 Fig. 2 is completely dissolved, the apparatus is allowed to stand for a few minutes to come to the room temperature. Then a label is placed on the tube to indicate the volume of hydrogen, the tube being held steady with a test tube holder to avoid warming the gas by contact with the hands. The volume of hydrogen is obtained by removing the test tube and filling

it with water from a burrette up to the label (Fig. 2). This volume is reduced to standard conditions and its weight computed. The ratio is then obtained between the weight of magnesium used and the weight of hydrogen obtained. It is seldom that the error amounts to 1 per We find the experiment particularly valuable immediately after studying Boyle's Law and Charles' Law.

ARE THE ELEMENTS TRANSMUTABLE, THE ATOMS
DIVISIBLE AND FORMS OF MATTER BUT
MODES OF MOTION?

BY PROFESSOR S. LAWRENCE BIGELOW, UNIVERSITY OF MICHIGAN

The advance workers in chemistry and physics are constantly accumulating new facts and propounding new theories which must be digested and incorporated in the body of the sciences. The process of assimilation is often slow, and it is right that new and important facts. should be vouched for by more than one investigator, and that a new theory should prove its usefulness, before being placed beside old and tried facts and theories. But too often the effects of the advances are unduly delayed through a reluctance to revise old text-books or old lectures, perhaps not so much because of mere laziness as because of a failure to appreciate the full force of the evidence in favor of new views, or of the advantages to be obtained by their adoption. The fact that the arguments for an innovation, for a time at least, are scattered through many journals, leads to an under-estimate of their cumulative force.

It is the purpose of this article to gather the main facts, some old, many recent, most of them fairly generally known, which are compelling us to alter our old definitions, and to show what a strong argument they make in favor of believing in the transmutation of the elements, the divisibility of the atoms and that what we call matter is simply a mode of motion.

It is interesting to note the caution with which text-books express themselves when it is necessary to give definitions for these terms. By a careful choice of words most authors avoid making false statements, but they certainly do frequently lead their readers to unjustifiable conclusions. For instance, in Roscoe and Schorlemmer's "Treatise on Chemistry, issued in 1891, we find the definition, “An atom is the smallest portion of matter which can enter into a chemical compound." As is the usual custom, the ideas of the alchemists regarding the possibility of transmuting metals is held up to ridicule, and thus, by implication at least, the ultimate nature of the elements and the

idea that the atom is indivisible is infallibly conveyed to the reader. A more recent instance is to be found, even in the late editions, of one of the most widely used texts on general inorganic chemistry. In this book, on page 4, we read, "Molecules may be defined as the smallest particles of matter which can exist in the free state;" on page 5, "Atoms are the smallest particles of matter which can take part in a chemical change;" on page 6, "Molecules consisting of atoms of the same kind are termed elementary molecules, and substances whose molecules are so constituted are known as elements." The numbers of the pages on which these statements occur are also significant. This reminds one of the methods of the old Greek philosophers, who pretended to solve all questions of science by pure deduction, positing some hypothesis, and then developing everything else by meditation in their closets, disdaining to disturb the order of their thoughts by experiments. But it is unworthy of the present age of inductive science, wherein every thought has, or should have, experimental evidence as its starting point. It can not be said that this particular author has made a false statement, but he has left the subject incomplete; cautiously reserving a loophole for his own escape, he fairly traps his readers. For it is inevitable that, with such didactic phraseology, and without having his attention called to the hypothetical, the tentative, nature of these definitions, the student should become convinced that the most fundamental facts of chemistry are that there are about eighty substances so simple that they can never be broken up into simpler things, and that all substances are composed of ultimate particles, called atoms, eternally indivisible.

A student started out with this hodge-podge of fact and theory thoroughly implanted in his mind as the basis for all his future knowl edge, is sadly handicapped, indeed he is intellectually maimed, and it may take him years to overcome the habit of confusing fact and theory, and to learn how to think straight; perhaps he never succeeds in overcoming it. This confusing of facts with theories is a vicious habit which grows till it colors all one's thoughts, hinders the free play of the intellect, diminishes the power of right judgment, and starts the ossification of the wits even before the age set by Dr. Osler.

It is not necessary to consider a student of chemistry as an infant in arms to be fed on predigested food. He may be assumed to have a digestive apparatus of his own. Give him the benefit of any doubt and ascribe to him at least a dawning intelligence, which, properly stimulated, may some day shed some light of its own. It is the characteristic course of a lazy teacher, and one pleasing to lazy students as well, to supply a lot of personal opinions in the shape of cut and dried definitions, so easy to memorize and, unfortunately, so hard to forget; phrases which do not require the intellect to bestir itself and exercise its faculty of criticism, to pass judgment for itself between alternative or conflicting views. Strictly speaking, nothing should be presented in

the form of a definition except what is, in itself, a statement of experimental facts, as for instance, we describe or define a unit of measurement in terms of other units. When dealing with a subject where more than one opinion is permissible, all should be stated, or at least, the attention should be directed to the fact that others draw different conclusions from the same premises.

The average student is better able to face issues and weigh arguments than most of us realize, and it is more important to educate those falling below the average in this particular than in any other. We should state the facts and then reason in such a way as to teach students how to think. It is indispensable for them to learn to think for themselves. Great stores of chemical facts are of but little real use, unless accompanied by an ability to adapt and to apply them in new conditions, unforeseen by either teacher or student in school or university days, but surely coming in after life. It is the prime necessity for research work or for originality of any kind, and we all are willing to admit that originality is what should be cultivated.

There is a great difference between the phrases, "elements are substances which can not be broken up" and "elements are substances which we have not as yet succeeded in breaking up," and we should mark well the difference. This caution, lest we slip into the error of stating as fact more than we really know is the distinguishing difference between the chemistry of to-day and the chemistry of a few years ago. It is more than this, it expresses concisely the difference between the way in which any science should be taught and studied, and the way in which it should be neither taught nor studied.

This particular differentiation between two definitions of the term element has been more than justified by the results which have followed the last ten years' work in pure chemistry, spectroscopy, radioactivity and Röntgenology (a term which has been seriously proposed by one of that fraternity which seems to consider its main function in life to be the coinage of new words).

The main arguments which may be marshaled in favor of considering the elements as ultimates, and the atoms as indivisible consist:

First, of all those facts which Dalton condensed into the laws of definite and multiple proportions, and to which there have been as many additions as there have been analyses and syntheses made before or since his time.

Second, Dulong and Petit's law that the atomic heats of all solid elements are the same.

Third, the isomorphism of many compounds containing similar elements, a phenomenon discovered by Mitscherlich.

Fourth, Faraday's law, that equivalent quantities of the elements are deposited at the electrodes during electrolysis.

Truly, an imposing array of evidence, and more than sufficient to justify us in making the assumption that atoms exist. But curiously

enough, there is not one item amongst all these facts compelling us to believe that these atoms are the ultimate constituents, or that they are indivisible. These later hypotheses are purely gratuitous, tacked of by Dalton and retained by succeeding chemists and physicists for no good reason. Perhaps because imitation is a characteristic, inherited from our simian ancestry and is so much easier for us than originality. Many a chemist looks askance at any tampering with the atoms, apparently fearing that it may hurt them, or even destroy them utterly and the atomic weights with them. Or he trembles for his spidery and tenuous structural formulæ, knowing full well that if deprived of these, he will be irretrievably lost in a labyrinth, without a thread to guide him. While, if he is not permitted to think of the carbon atom as a little chunk of matter, tetrahedral in form, he thinks he is launched on a sea of troubles.

But all this apprehension arises from a misunderstanding. That the atomic weights remain unharmed and unaltered, as the units for chemical calculations, and that nothing which is good or useful about the atomic theory is destroyed or even assailed by the new ideas, that the trend of these new ideas is unmistakably constructive and not destructive, is best shown by a review of the arguments in favor of the hypothesis that the atom is divisible, and that our elements are not elements in the true sense of the word.

There is nothing new in this view; it formed the first article of the faith of the alchemists. It was unqualifiedly denied by Dalton, and fell into such disrepute that even within recent years one risked being called a dreamer, or even a fool, if he dared to consider it possible. Here again is an instance of the desirability of being as precise as possible in the use of terms. Many believe experimental evidence of the complexity of "elementary atoms" and the existence of one "mother substance" must be followed immediately by directions for transforming elements into one another; by the transmutation of baser metals into gold. But these are two wholly distinct propositions. An astronomer might locate a mountain of gold on the surface of the moon, but there would still be a goodly chasm to bridge before he derived much material benefit from his discovery!

The idea that there is one fundamental substance would not down. The hypothesis of the English physician, Prout, is a familiar one. When the atomic weight of hydrogen is set equal to unity, the atomic weights of all the other elements come out remarkably closely to whole numbers. There exist numerous groups of three elements, commonly called Döbereiner's triads, the individual members of one group being similar in their chemical properties, and so related that the atomic weight of the middle member is the arithmetic mean of the atomic weights of the extreme members. These are the facts which led Prout to suggest that there was but one element, namely, hydrogen, the others being complexes containing different quantities of this ultimate substance. It

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