all the exquisite metallic shades which diaper the feathers of birds and the wings of butterflies arise from pigments; it was a dream of the alchemists to try to extract them. Their sole cause is the play of light, fugitive as the sparkles of the diamond. When the beautiful feathers on the breast of a humming-bird are examined under the microscope, it is astonishing to see none of the shades the mystery of which you would penetrate. They are simply made of a dark-brown opaque substance not unlike those of a black duck. There is, however, a remarkable arrangement; the barb of the feather, instead of being a fringed stem, offers a series of small squares of horny substance placed point to point. These plates, of infinitesimal size, are extremely thin, brown, and, to all appearance, exactly alike, whatever may be the reflection they give. The brilliant large feathers of the peacock are the same; the plates are only at a greater distance, and of less brightness. They have been described as so many little mirrors, but that comparison is not correct, for then they would only give back light without colouring it. Neither do they act by decomposing the rays which pass through them, for then they would not lose their iris tints under the microscope. It is to metals alone that the metallic plumage of the hummingbirds can be compared ; the effects of the plates in a feather are like tempered steel or crystallised bismuth. Certain specimens emit colours very variable under different angles, the same scarlet feather becoming, when turned to ninety degrees, a beautiful emerald green.

The same process which nature has followed in the humming-bird is also found in the wing of the butterfly. It is covered with microscopic scales, which play the part of the feather, arranged like the tiles of a house, and taking the most elegant forms. They also lose their colour under magnifying power, and the quality of reflection shews that the phenomena are the same as in feathers. There is, however, a difference in the extent of the chromatic scale. Whilst the humming-bird partakes in its colours of the whole of the spectrum from the violet to the red, passing through green, those of the butterfly prefer the more refrangible ones from green to violet, passing through blue. The admirable lilac shade of the Morpho menelas and the Morpho cypris is well known, and the wings of these butterflies have been used by the jewellers, carefully laid under a thin plate of mica, and made into ornaments. A bright green is not uncommon, but the metallic red is rare, excepting in a beautiful butterfly of Madagascar, closely allied to one found in India and Ceylon. The latter has wings of a velvet black with brilliant green spots; in the former, these give place to a mark of fiery red. There is the same difference between the metallic hues of creatures endowed with flight and the iris shades of fishes, that there is between crystallised bismuth and the soft reflections of the changing opal. To have an idea of the richness of the fish, it is only necessary to see a net landed filled with shad or other bright fish. It is one immense opal, with the same transparency of shade seen through the scales, which afford the only means of imitating pearls. It is due, however, not to the scales, but to extremely thin layers lying below the scales under the skin and round the blood-vessels, which look like so many threads of silver running through the flesh. Réaumur first noticed and described

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them; sometimes their form is as regular as that of a crystal, and of infinitesimal size and thickness. The art of the makers of false pearls is to collect these plates in a mass from the fish, and make a paste of them with the addition of glue, which is pompously named 'Eastern Essence." This is put inside glass beads, and gives them the native whiteness of pearls.

Many observations have been made lately by our naturalists as to the defence which colour supplies to animals: hares, rabbits, stags, and goats possess the most favourable shade for concealing them in the depths of the forest or in the fields. It is well known that when the Volunteer corps were enrolled, and the most suitable colour for the riflemen was discussed, it was supposed to be green. Soldiers dressed in different shades were placed in woods and plains, to try which offered the best concealment. Contrary to expectation, that which escaped the eyes of the enemy was not green, but the fawn colour of the doe. Among hunting quadrupeds, such as the tiger, the leopard, the jaguar, the panther, there is a shade of skin which man has always been anxious to appropriate for his own use. The old Egyptian tombs have paintings of the negroes of Sudan, their loins girt with the fine yellow skins for which there is still a great sale. All the birds which prey upon the smaller tribes, and fishes like the shark, are clothed in dead colours, so as to be the least seen by their victims.

There is an animal which, for two thousand years, has excited the curiosity and superstition of man by its change of colour-that is, the chameleon. No reasonable observation was ever made upon it, until Perrault instituted some experiments in the seventeenth century. He observed that the animal became pale at night, and took a deeper colour when in the sun, or when it was teased; whilst the idea that it took its colour from surrounding objects was simply fabulous. He wrapped it in different kinds of cloth, and once only did it become paler when in white. Its colours were very limited, varying from gray to green and greenish brown.

Little more than this is known in the present day: under our skies it soon loses its intensity of colour. Beneath the African sun, its livery is incessantly changing; sometimes a row of large patches appears on the sides, or the skin is spotted like a trout, the spots turning to the size of a pin's head. At other times, the figures are light on a brown ground, which a moment before were brown on a light ground, and these last during the day. A naturalist speaks of two chameleons which were tied together on a boat in the Nile, with sufficient length of string to run about, and so always submissive to the same influences of light, &c. They offered a contrast of colour, though to a certain degree alike; but when they slept under the straw chair which they chose for their domicile, they were exactly of the same shade during the hours of rest-a fine sea-green that never changed. The skin rested, as did the brain, so that it seemed probable that central activity, thought, will, or whatever name is given, has some effect in the change of colour. The probability is, that as they become pale, the pigment does not leave the skin, but that it is collected in spheres too small to affect our retina, which will be impressed by the same quantity of pigment when more extended.

It is undoubtedly the nerves which connect the brain with organs where the pigment is retained. By cutting a nerve, the colouring-matter is paralysed in that portion of the skin through which the nerve passes, just as a muscle is isolated by the section of its nerve. If this operation be performed on a turbot when in a dark state, and thrown into a sandy bottom, the whole body grows paler, excepting the part which cannot receive cerebral influThe nerves have, in general, a very simple and regular distribution: if two or three of these are cut in the body of the fish, a black transversal band following the course of the nerve will be seen; whilst, if the nerve which animates the head is thus treated, the turbot growing paler on the sand, keeps a kind of black mask, which has a very curious effect.

ence.

These marks will remain for many weeks, and what may be called paralysis of colour has been remarked in consequence of illness or accident. Such was seen in the head of a large turbot, the body being of a different colour. It was watched, and died after a few days, evidently of some injury which it had received. The subject offers a field of immense inquiry: the chemical and physical study of pigments, the conditions which regulate their appearance, their intensity, and variations under certain influences; the want of them in albinos, and the exaggerated development in other forms of disease. To Mr Darwin, in England, and to M. Ponchet, in France, the subject is indebted for much research, which will no doubt be continued as occasion offers.

CHAPTER XXXII.-THE SECRET WITNESS.

"THAT's it, madam, nothing less,' observed Blake, with brutal coolness, after a short pause, during which Maggie for the first time withdrew her eyes from his, and fixed them on the ground.

"Tis just murder that this excellent husband of yours has committed; and as though even that were not enough, the man he has killed was his own brother. Do you hear that?'

'I hear you say so,' was Maggie's answer, delivered in such unmoved tones that they surprised herself. Her weakness had been but momentary, and now that she was face to face with the worst, she felt the courage of despair.

'You'd be game to the last, I knew,' continued Blake, with sort of grudging admiration; or it may be that, so far as I have gone as yet, you may think me a liar. One of that trade, however, it ought to strike you, would not have told you so improbable a story-would have stuck to something a little less strong, but more like truth.'

It did so strike her; and though she did not believe the fact-she would as easily have been persuaded that the sun was black, as that John Milbank was a murderer-she did believe that Dennis Blake was stating what he deemed was true. Remembering what her last reply had cost her, she answered him by a haughty gesture expressive of incredulity and contempt.

'Well, it is something that one can get you to

listen,' continued the other dryly; that you don't fly out, as some fools would in your case, into a passion and clamour that would ruin all. I always thought you a sensible woman, except as regarded Master Dick- There, there; I'll say no more about that, then '-for Maggie had risen with such a look of rage and scorn upon her face, as bade him pause-' but will proceed to the proof at once.-I no more thought at first, as I have said, of anything more serious than a quarrel having happened between the two brothers, than you did, notwithstanding it was clear to me John had some good cause for concealing that Richard had returned to him that night; and even when the lost man did not turn up, I took the other's word for granted, that he had left the town, notwithstanding the private reasons I had for holding his departure to be unlikely. If, indeed, I had had any ground of suspicion of your husband, I should have worked upon it then, and much more, you may be sure, after I got this'he moved a lock of dark hair aside, that hung over his forehead, and shewed a deep white scar. If I could have hung him then, by Heaven! I would have done it, without ransom! To see him swing, would have been dearer to me than a mountain of gold!' The vehemence and passion with which Blake pursued this topic, contrasting, as they did, with the calculating coldness he had hitherto displayed, were most remarkable, and shewed but too well that gain was not the only object, nor perhaps even the chief one, that he had in view. To think that for speaking lightly of a girl like you, a man should be so mauled as this' here he snarled like the cur he was, and shewed a row of teeth with which art had supplied him, in lieu of those which John's hit from the shoulder had destroyed-'a girl, who, if she was not the thing I called her, was something worse, and cast one brother off for another as easily as one changes shoes. To think, too, that the man who struck me-that miracle of virtue, and soul of honour, as folks deemed him, so sainted, that he could not himself the right of chastising him who uttered listen to a broad jest, but must needs arrogate to it-to think that this man, I say, was a felon, a murderer, whom I could have sent to jail and to the gallows, with a word! If I could have laid him dead, I would have done it, even then; but now-knowing what I do-I feel, aye, as though I could tear his heart out with my hands! You, you too'-he broke out with a fresh access of fury, and pointing at her with a trembling finger do you think I will spare you, any more than him, now my time has come ?'

'Is this the proof that you have to shew me of my husband's guilt?' inquired Maggie coldly. At present, I only see the evidence of such malevolence and hate as would have sufficed to forge a proof.'

'It was not necessary to forge it, madam,' answered the other, with a bitter sneer, 'as I shall presently shew you. About that time-I am

speaking of eighteen months ago-I had my own misfortunes'

'Let me describe them,' interposed Maggie, in the same clear voice she had used at the beginning of their interview. 'You lost what little selfrespect you had, and took to cheating your acquaintances at cards; you were turned out of the club, and reduced to beggary; I have seen you in the street, myself, in rags.'

'I am not in rags, however, now, madam,' continued Blake, who seemed to have repented of his recent outbreak of passion, and to have recovered his self-control; and thanks to the knowledge I possess, and am about to communicate to you, I am not likely to be in rags in future. Your delicate reference to my late condition is, of course, meant to suggest that my testimony is not unimpeachable. That might be so, if it rested upon my word alone; but it does not. I was foolish to fly in a passion, from the mere remembrance of the past, when so much can be remedied; you were still more foolish to taunt me with my humiliations. Let us proceed with the main business. I was poor; I was reduced to such sore straits that -I own to you frankly-I would have stuck at nothing. In my palmy times, I had often feasted in this very room, and eaten and drunk-especially drunk-of the best; and while casting about me in London for a livelihood, it struck me that something could be got at Rosebank, which would never be missed by its present owner, while it would have put me in funds. I allude to the wine in your husband's cellar'-he stopped a moment, as though to select his words, and then continued, in a harsh dry tone, as follows: I had heard that John Milbank had bricked up that cellar on the very day that his brother left his roof -for what reason, I knew not, though I can guess it now; and hence, if I could only gain admission to the place, I might, it struck me, get all I wanted, without the risk of discovery. With this intention, I returned to Hilton some weeks ago. With the premises here, I was tolerably familiar; but before entering upon my project, I surveyed them with great particularity, taking care to select those times when your husband was at his office. Nothing would have been easier than to have removed the iron grating outside the cellar, but that would have been to have revealed the robbery-I am very plain-spoken, you see, madam, and call a spade a spade-and besides, it was my object to take all the contents of the place, which would have required several nights for their removal. On the whole, therefore, I judged it best to dig into the cellar from the toolhouse. The stock of wood for winter use was large, and would conceal my operations; the spade and pick were ready to my hands. My time was not valuable, and my gain was certain. It was altogether an excellent plan, and I worked it out to perfection. When I had nearly accomplished my purpose however, and drew near the cellar wall, my difficulties increased, since, once under the house, every blow of my pick was liable to be heard by those above; and though I took every precaution, even to removing the bricks one by one, this did in fact happen, for your husband was disturbed, and discovered me in the very act. You will ask then, madam, how it was that, having no particular liking for your humble servant, he should, under

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such circumstances, have held his hand-that had once been so quick to avenge your fancied wrongs, or forborne to give me over to the tender mercies he discovered me in the cellar, I had happened of the police. The reason of this was, that before to discover Something there myself. It was not very much-only some clothes and some bonesPermit me to pour you out a glass of water.'

If she had been told at any time during the last two years that, under any possible circumstances, she could have been persuaded to take even so much as a glass of water from the hand of Dennis Blake, Maggie would have indignantly denied it; yet she took it now, and almost felt grateful to him for that trifling service. Her vital powers and her reason seemed to be alike deserting her, and that at the very moment when she most required resolution and decision.

The shock is severe, no doubt,' continued her companion grimly, when the colour began once more to faintly tinge her cheek; 'I felt it to be so myself, I do assure you, when that spectacle first met my gaze. To come at midnight, and in the very bowels of the earth, as it were, upon the body of an old acquaintance, lying doubtless on the very spot where he had met his death-it was at the foot of the stone steps '- Maggie held up her hand imploringly, for had she not beheld that very spot herself, with its dark stain on the stone floor, that she was now persuaded had been Richard's blood!

'I have no desire to distress you, madam, more than is absolutely necessary,' resumed Blake coldly. 'So long as you understand the fact, the details may well be spared. I will not even mention the poor victim's name, whose remains lie at this moment exactly as I have described, beneath this very room-under our very feet! The verification of my statement-or its disproof-is easy; but I will suppose that you accept it. There is no more choice for you, indeed, than there was for your husband himself when he found me yonder' -he pointed with his finger downward-'in possession of his ghastly secret. I think there was a moment when he thought to kill me also, and thereby conceal the evidence of his first crime by a second; but I was armed; or perhaps he had already had enough of blood-shedding. I know who this was, and by whose hand he came by his end," said I. He made no effort to deny it, but stood speechless, overwhelmed with remorse and terror. I was frightened myself, I own, and eager enough to get to the upper air. "Go first," said I (for I was not so foolish as to let him come behind me); and he obeyed me like a child. When we got to the toolhouse, I put the wood back over the hole with my own hands, for he seemed quite helpless, and gazed at me like one walking in his sleep. When I told him, however, by way of comfort, how fortunate it was that an old acquaintance like myself, who understood the relations between him and his brother, and could make allowance for great provocation, had discovered his secret, since it would remain quite safely in my hands-upon certain equitable conditions-he seemed to recover himself a little, and be inclined to listen to reason. the other hand, it was foolish in him, and a mere waste of breath, to endeavour to explain to me that the whole affair had happened by accident. That might have been the case or not; if it was so, it was no doubt a matter for his private satisfaction;

On

but so far as I was concerned (as I pointed out to him), it could not make one half-pennyworth of difference in my pecuniary demands. Again, it was still more foolish in him-the man who had struck me down in the open street-to attempt to appeal to my compassion. I refer to it, however, for two reasons: first, because his stooping to such a humiliation will bring home to you more than any words of mine the fact that he lay-and lies-completely in my power; and secondly, as a guide for your own proceedings. You have heard of a heart of stone; but stone may be worn away, they say, by water-drops, and therefore, perhaps, by woman's tears. My heart is made of sterner stuff. Besides, I hate you both, and would not spare you a single turn of the rack-so long as it kept life in you.' 'Monster! what is it you demand?' asked Maggie hoarsely.

Money! A round sum down. So much paid quarterly and to the very day. It will not beggar you; you will not go about in rags, as I have done; but you will be poor, and I shall be rich. Money!'

'I will not give you one farthing, though it were to save your soul.' She had risen from her chair, and stood confronting him with pale resolute face and unshrinking eye. Thief, by your own admission; coward, by your presence here; liar, by the story you have fabricated against my husband's honour, I will give you nothing-nothing! I defy you !'

'O ho, madam, so you guessed it from the first, did you,' answered he, 'and made up your mind to fight it out? Have you forgotten, then, what I told you a week ago, that I have in my possession-I have it here the proof, the damning proof of what I have told you, in your husband's own handwriting? Do you suppose that I trusted to his bare word? No, no. Here it is, in black and white-his own admission.'

'Let me look at it.'

She had moved towards him, and he stepped back towards the curtained window, to avoid her. 'Gently, gently. Keep your distance, madam. I am not going to let your nimble fingers touch a document that is worth to me five thousand pounds at least.'

'It is worth nothing: I do not believe in its existence. It is just as likely as not to be blank paper, and all this wicked talk a scheme to extort money from a defenceless woman. Let me see it,

I say.

You shall see it, but at safe distance,' replied Blake, still retiring before her.

'That means, it is a forgery,' answered Maggie boldly.

'Forgery or not, madam, it shall never leave

my'

Here the curtains opened behind the speaker, a strong arm stretched over his shoulder, and plucked the paper from his grasp; he turned round with the cry of a wild beast, and found himself face to face, not with John Milbank, as his fears foreboded, but with the inspector of police!

'I will shew the document to the lady myself,' said Mr Brain.

CHAPTER XXXIII.-CHECKMATED.

It would have been difficult for the most skilful of physiognomists to detect the chief among the various passions that convulsed the countenance

of Dennis Blake, on finding himself disarmed of the weapon wherewith he had proposed to win so much. For an instant, he glared savagely at the inspector, as though resolved, at all hazards, to regain the document of which he had been so unceremoniously dispossessed; but there was such an unmistakable look of power in the well-built frame of his opponent, as he stood with his hand behind him, and the paper in it, and such an obvious 'You had better not' in his resolute features, that he seemed to abandon that idea as hopeless. But the rage in his face remained no less vehement for being baffled; and mingled with it was a fear that blanched even his dusky cheek. Irresolution, too, had as evidently seized him, as he glanced from one to the other of his two companions, uncertain to which side to attach himself, labouring between the slender hope of yet securing his object, or the immediate gratification of revenge. The former consideration seemed at last to prevail with him, for, after a full minute of troubled thought, he thus broke silence :

'I hope, Mr Inspector, that you know the world too well, to have taken all that I have been saying to Mrs Milbank here, for granted. I confess, I was putting the screw on a little more tightly than the circumstances warranted, but that would have been explained all in good time. It is a case, I do assure you, which does not require your intervention at all. Though, I will answer for it, that shall not have cause to regret your loss of time here. The little affair between myself and this lady may be very well settled out of court, but at the same time, you shall occupy the post of arbitrator-so far as the fee goes-and it shall be a large one.'

you

Mr Brain did not reply, but turned an eye interrogatively towards Maggie, keeping the other, as it were, on guard upon his interlocutor.

For my part, answered Maggie resolutely, 'I wish to enter into no terms whatever with this man, whom I know to be a liar and a villain. I believe no word of what he has been telling me; but that he has founded his whole story upon some scandalous rumour, taking advantage of which, and of my unprotected and miserable condition, he has sought to extort money from me. That paper, I say again, if it be anything-if it be not a mere sham and pretence, with which to crown his infamous scheme-is but a forgery of my poor husband's handwriting, and will be proved so in any court of justice.'

"Have I, then, your permission to read it, madam?' inquired the inspector.

There was a melancholy gravity in his face that to Maggie's eye foreboded ill. There had been points in that long act of accusation to which they had both been listening, that had struck home with something of conviction even to her heartthough it did not waver even now in its allegiance to her husband; her own answers, specially framed though they had been to meet the ears of a third person, had not always, she was conscious, been such as to throw doubt upon Blake's story, and it might well be that the very man she had invoked for her protection was, in spite of himself, already committed to the other side. Still, all the more reason was there to put entire trust in that little weapon, the time for using which had now arrived; and to give proof of her confidence in John's innocence, by daring all.

'Read it, Mr Brain, by all means,' cried she, and read it aloud. Whatever it may say to my husband's prejudice, will be false, I know, as the knave who has brought it hither. I have nothing to fear from it, nor, thanks to your presence here, from him.'

'Are you mad, woman ?-Stop, stop, sir!' broke in Blake, with vehemence, and stretching a hand out, in his excitement, that unintentionally struck against the inspector's chest. The next moment, he was staggering to the other end of the parlour, half-stunned by a buffet from that official's fist.

'Hands off!' exclaimed Mr Brain, in a warning voice. I have enough against you already, without your adding assault and battery to the list of your offences. It is, as you say, madam, very well that we arranged this little plan together beforehand that I am here to protect you from the violence of a scoundrel who would stick at nothing.'

In spite of this rebuff and denunciation, Dennis Blake once more lifted up his voice in earnest appeal to Maggie. 'I adjure you, madam, to forbid this man to read that paper, or you will repent it to your dying day.'

Read it, Mr Brain,' repeated Maggie steadily, 'and aloud, if you will be so good.'

That's easier said than done, ma'am,' cried the inspector, who had already unfolded the document. 'Why, this villain, this extortioner, has been trading upon absolutely nothing! Such a specimen of audacity, I have never beheld, in all my professional experience! Why, the paper is blank!'

'Blank!' echoed Maggie, in a tone of wonder, that needed all her self-command to counterfeit her heart was as overpowered with gratitude as though a miracle had interfered in her husband's favour. The weapon, then, to which she had trusted had not failed her the virtues of her father's darling invention had been proved indeed, in a manner, and with a result, that his wildest fancy could never have pictured. How little, too, could John have thought, when he flattered the old man's whim, and helped to make it a reality, that it should one day be the instrument of his own safety, and of his enemy's confusion !

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ugly customer indeed. I could have given you a tap with my truncheon, mind you; but that would have been to rob the gallows of its rights.' 'She has bribed you,' gasped Blake hoarsely. 'Ah, with the money that she should have given you, I suppose,' chuckled Mr Brain, regarding his prisoner with much complacency. You are-you really are a specimen, in the way of scoundrels: quite perfection, upon my life.'

'I tell you, this is false imprisonment, and you shall pay for it,' continued the other, choked as much with rage as want of breath. It is on that woman's wrists-as accessory after the fact to a murder; I have said so, and I can prove it-and not on mine, that you should put these things.' He held up the manacles as he spoke, and shook them at her in impotent malice. Do you think your husband will escape my vengeance, through this device, you jilt, you trickster'

'Gently, gently,' broke in the inspector sternly. 'No hard words to any lady in my presence, or I'll gag you!'

'I say that John Milbank has committed murder,' continued Blake excitedly-'the murder of his own brother Richard, and that that woman knows it. I accuse her of being his confederate, and I charge you, inspector, to do your duty, without fear or favour, and arrest her as such !'

'I should think you were a sort of gentleman whose sense of duty is most uncommon powerful!' observed Mr Brain, leaning his head aside, and scratching it in the excess of his moral approbation. 'I don't wonder that the notion of another person's neglect of it should fill your breast with virtuous indignation; not at all. The very finest specimen, upon my honour, of impudence; no imitation, but the genuine scoundrel, with the true ring about him: brass, from skin to skin.'

'I don't care what you say of me-I don't care what you do to me,' gasped the wretched man, 'only take the charge. I say it's murder, and I can prove it. You're a policeman, and you have no choice but to obey the law?'

I am a policeman, as you say, Mr Dennis Blake,' observed Mr Brain coolly, though, since I am an inspector, it would have been more civil to give me my title; and, as a policeman, I will just tell you how this case strikes me. I have heard your story with my own ears; and some of it I believe, especially that part of it where you acknowledged that you had broken into this house with felonious intentions. I happened to have discovered that underground passage, which, it seems, was your own handiwork, myself, and have, by means of it, explored the cellar. There are no "dead men" there, unless it's an empty bottle or two, which are sometimes called so, nor, in my opinion, have there ever been such.'

by the stone steps, with my own eyes!'

If you was as strong as you are vicious,' remarked the inspector, taking out his handkerchief, and mopping his forehead, 'you would be a very

"You have said that already, Dennis Blake; but when you said it last, you promised that there was the proof to follow. Do you call this white sheet of paper a proof of murder? It looks to me more like a proof of innocence !'

'It bore John Milbank's confession, the last time I looked at it,' cried the other vehemently. You have changed it for another. I say again, this woman has bribed you!'

'That statement is slander,' observed Mr Brain