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go into the house, and slip into your overalls. We'll be shifting camp in less than half an hour.'

'Dad!'

'Well ? '

T's true, then?'

He smiled grimly.

'Yes-it's true.

Get a move on you. Mr. Wells and I are

going to have a little talk.'

She walked slowly towards the hut; then suddenly she turned, flying back on nimble feet.

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'Dad,' she said quickly. Mr. Wells will help us, if you ask him, if—if I ask him.' She approached Jeff. I told you that your duty was to the State,' she continued, but I take that back. Do you hear? Save Dad! I don't care what he has done to others, he's always been so good to me.

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And if you will help us, I

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She moved away, the tears trickling from her eyes. Nothing was said till the door had closed behind her; then Jeff broke the silence, in a voice with a strange rasp to it.

'I will help you, Mr. Quincey.'

Quincey thrust his weapon into his pocket, and came close to the speaker, eyeing him attentively. An impartial observer might have pronounced the younger man to be the defaulter.

'You'll help me-eh? How?'

'I can get you safe into Mexico.'

'Can you?'

'At a word from me the sheriff 'll be huntin' somewheres else. See?'

'I see.'

'Don't think you'll squeeze through without me. I reckon you've a springboard and a buckskin in the barn over there?' 'Maybe.'

'The officers are looking for that buckskin in every little burg between Santa Cruz and San Diego. You can't pack your grub and blankets a-foot. I can supply everything. Nobody'll suspect me.' 'Why not?'

'Because-because o' my record.'
'Oh. It's a clean one, is it?'

'It is that.'

Sadie cottoned to you right away. Because she sized you up as straight, I surmise.'

The speaker smoked silently for a moment; Jeff held his tongue, but his cheeks were red and hot.

'Sadie may sour on me now,' said the father heavily.

'Sour on you, Mr. Quincey! Not she.'

Quincey frowned. Then he opened a knife and slashed the cord which bound Jeff. The fingers which held his pipe were trembling.

'You'll let me fix things?' said Jeff, in a low voice.

'And then-suppose-suppose Sadie soured on you?'

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'I'll risk that,' Jeff answered slowly. She's more'n likely to.' 'Um.'

'You're going to give me a free hand?'

'No.'

The monosyllable burst from his lips with a violence that indicated the rending asunder of strong barriers.

'No,' he repeated. One of us, Jefferson Wells, must be an honest man. I ain't going to whine about the luck, but I stole -I stole for her. I wanted to give her what she'd always had from me a pretty home, nice clothes, a good time. And what's the result?' He laughed hoarsely. 'This-this hut, those overalls, beans and bacon to eat, and now-now-the knowledge that her dad is a thief. Well, she's cottoned to you. I read it in her face. Quick work, they'd say back east, but in this new country folks have to think quick and act quick. I can think quick and act quick. You want her?'

'Worse than I ever wanted anything in my life.'

'You can take care of her?'

'I am well fixed. A nest-egg in the bank, a good salary, and a pair of arms that can carry a heavier load than she'll ever be.'

Quincey nodded; then he spoke very deliberately: 'I'm going back to Santa Barbara to face the music. I shall give myself up. Hold on-let me finish! I know something of women, and Sadie is the daughter of a New England mother. It's lucky she's dead, poor soul! Don't you ever dare to tell Sadie that you weakened. When she lies awake nights-and she will-it may comfort her some to think that her husband is an honest man. I'm going to take the trail now. When Sadie comes out o' there, tell her, with my love, that I've left her in your charge.'

523

THE NEW CHEMISTRY.

II. THE MECHANICS OF CHEMICAL CHANGE.

IN science, as in every other field of human endeavour, the centre of interest is for ever shifting. Yesterday the chemico-biological discoveries of Pasteur and his colleagues held us all enchained. The day before, Faraday's researches in electricity riveted attention. To-day we all watch the borderlands where chemists and physicists are busy unravelling the mystery of radium and radio-activity. But at all times side by side, or perhaps I should say underneath, these waves of thought, if I may call them so, great currents flow quietly, steadily, and, by most of us, unseen, which are not less important than the more visible disturbances, however great these may be.

One of these great currents forms the subject of this article.

I wonder if my readers have ever pondered on the subject of the great force which presides over those changes, called chemical changes, which play so tremendous a part in the world we live in? Most of them, no doubt, have often heard the term 'chemical affinity.' A few, perhaps, have a tolerably definite idea that by chemical affinity we mean the cause of chemical combining; the property of the chemical atoms which causes them, as we say, to unite and form all the thousands and thousands of combinations which we meet in nature and which chemists produce in their laboratories. Probably very few are aware of the fascinating researches and speculations on this subject which have occupied the minds of chemists more or less continuously for many centuries. And yet the results of these researches and speculations are hardly less interesting, and hardly less mysterious, than that exciting substance radium and the other radio-active substances, though, as I have said, they are by no means equally familiar to most of us.

It would be absurd, here, to attempt to trace back the history of this subject to the thirteenth century, when Albertus Magnus, Bishop of Regensburg-who was said to be magnus in magia naturali, major in philosophia, maximus in theologia—an upholder of the birds-of-a-feather-flock-together theory of chemical action, employed

the word 'affinitas' to express the idea that substances which combine must have some kinship, something in common. Partly because this idea ignored the very obvious fact that the substances which combine most vigorously are just those which are most unlike one another, but still more because until Robert Boyle-the father of chemistry and the uncle of the Earl of Cork '—had taught us in his famous book 'The Sceptical Chymist' (1661) to discard the elements of Empedocles, earth, air, fire, water,1 and enunciated the modern axiom that we must regard as the true elements' those substances which have never yet been decomposed, no real investigation of the subject from the modern point of view was possible. Even after the publication of The Sceptical Chymist the rate of progress was slow, so that late in the seventeenth century we find Lemery, the author of one of the most successful books on chemistry at this period, committing himself to the fanciful idea that combination between two particles, e.g. between metallic particles and particles of sulphur, depends on the particles of one element being provided with spines or sharp points, and on the particles of the other being porous, the act of combining itself consisting in the fitting of the spines of the one more or less perfectly into the pores of the other. Nevertheless some progress of a useful kind was soon made. After Boyle, chemists began to explain the simpler phenomena of combination and decomposition in terms which show that the idea of the selective character of chemical attraction, to which we shall recur, was beginning to be grasped by the leaders in the science. And at this time also we find them drawing up tables of affinity for the various acids and alkalis which, though they have not survived, did good work by directing attention to the important point that the strength of chemical attraction in any given case is not a fixed quantity, but varies with temperature: a fact which was brought out by the circumstance that it was necessary to construct different tables of affinity for low temperatures, moderate temperatures, and high temperatures. At one time there was a disposition to confuse chemical attraction with the attraction of gravitation. But Newton and Bergmann, the great Swedish master, saw clearly that, as the former acts only at very minute distances while the latter acts at immense distances, there must be some difference between them.

When Liebig began to send his famous 'Familiar Letters on Chemistry' to the 'Augsburger Allgemeine Zeitung' more than 1 Usually attributed to Aristotle.

half a century ago, he was able to dispose of the subject of 'Chemical Affinity' in a very few pages in one of the earlier letters. In order,' he says, 'to obtain a clear and vivid comprehension of the almost miraculous order and regularity in which bodies enter into combination with each other, we must bear in mind the meaning the chemist attaches to the terms combination and decomposition,' since all or nearly all the more familiar chemical phenomena depend upon these. And he went on to tell his generation that the ultimate causes of these chemical phenomena are 'chemical forces' which 'differ from all other forces, inasmuch as we perceive their existence only by their manifestations when bodies come into immediate contact with each other.' Also that this chemical force or 'chemical affinity' is strongest between elements which differ most in their general properties, and weakest in the case of elements which are members of the same or allied families. And, again, that the action of chemical affinity' may be modified by means of heat and by the presence of water or other solvents to such an extent that the chemist can use the different behaviour of substances in solution in different liquids, and their deportment at high temperatures, as a powerful means of analysis in the laboratory.

To-day this matter seems by no means so simple. On the contrary, it positively bristles with unsolved questions which are at once, if I may be excused the paradox, sources of obscurity and of enlightenment.

But the truth is that even in Liebig's time the question of the nature of chemical affinity and its mode of action was not so simple and well understood as we might suppose from some of the writings of that period. Chemists were too busily occupied just then in laying the foundations of organic chemistry and physiological chemistry, and, generally, in extending the boundaries of their science and occupying new and recently acquired fields of research, to have much time to study affinity.

The fact is that nothing is more difficult than to state clearly the relative affinities of half a dozen common elements. We can measure the masses of the atoms of these elements, though millions of millions of millions of them can go into a lady's thimble. We can compare their powers of conducting heat and electricity, find their melting-points, and learn a dozen other things about them with considerable certainty. But when we attempt to decide whether an atom of an element A or an atom of an element B has the greater attraction for an atom of a third element C, we find

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