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amount of skill to do it properly. The workman, by a sort of intuitive knowledge, gained by long experience, knows, on a careful inspection of the stone, the exact direction which a cleavage plane passing through the flaw will take. Tracing this plane therefore to the exterior, he makes on the edge of the stone, precisely in that spot, a slight nick with another diamond. He then places a small knife in that nick, gives it a light tap with a hammer, and the stone at once cleaves in two, directly through the flaw. This operation, in daily practice in the Amsterdam works, is one of the most elegant and instructive processes in the whole range of mineralogy. is reported that Dr. Woilaston, celebrated as almost the originator of the science of crystallography, once made a handsome sum by purchasing a large flawed diamond from Rundall and Bridge at a low price, and subsequently splitting it into smaller sound and valuable stones; the principle of the operation not being then generally known.

It

Another use of the cleavage principle is in the preparation of diamond powder. Small diamonds of inferior quality, are put into a steel mortar, and pounded and rubbed with a steel pestle, when they break up through their various cleavage planes into still smaller pieces, and at last rub themselves into the finest dust, fit for use on the wheel.

The cause of the wonderful brilliancy of the diamond is not popularly known. It has no inherent luminous power; it is simply transparent, like common glass, and yet, if the latter were cut into the form of a brilliant, it could no more be mistaken for a real one than for a sapphire or an emerald. The secret, therefore, of the brilliancy of the diamond must lie in something other than its clearness or its transparency. It is owing to its great refractive power. When rays of white light pass through transparent substances they are fracted, or bent out of their former course, and under certain circumstances are separated into their constituent ele

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well-known prismatic colours. The cut drops of glass chandeliers show a familiar example of these properties. Now, the degree in which this effect is produced by any substance depends on the refractive power it possesses, and it so happens that the diamond has this power in an extraordinarily high degree, its index of refraction being 2.47, while that of glass, or rock crystal, is only about 16, and of water 1.3. The effect of this great refractive capability, particularly when aided by judicious cutting, is, instead of allowing the light to pass through, to throw it about, backwards and forwards in the body of the stone, and ultimately to dart it out again. in all sorts of directions, and in the most brilliant array of mingled colours; and this is this marvellous effect that meets the eye. Sir David Brewster has shown1 that the play of colours is enhanced by the small dispersive power of the diamond, in comparison with its refractive properties.

It is often supposed that diamonds are essentially colourless, but this is a mistake; they exist of many colours, yellow, orange, pink, blue, green, brown, and black. Three-fourths of the stones found are tinged with some colour or other, mostly pale yellow, or yellow brown. The perfectly pure and colourless ones are selected as the most valuable for the general market; but it sometimes happens that fine stones of a decided colour are more prized than white, from their peculiar rarity and beauty.2 A blue diamond of about fiftysix carats, belonging to Mr. Hope, is a celebrated stone, combining the beautiful colour of the sapphire with the fire and brilliancy of the diamond.

The quality of diamonds depends upon their colour, purity, transparency, and freedom from flaws. Stones perfectly colourless, pure, clear, and free from all defects, are said to be of "the first water;" if they have slight imperfections, they are "of the second water;"

1 North British Review, Nov. 1852.

2 A fine collection of coloured diamonds, belonging to Mr. Tennant, are now exhibiting at

and, if tinged with colour, or otherwise very defective, of "the third water.”

The value is estimated according to the weight, which is expressed in carats; one carat being about 205 French milligrammes, or 3 grains troy.

For small stones, not exceeding one carat in weight, the value may be assumed approximately to be proportional to the weight; but, as the stones increase in size, this rule does not apply the larger ones being more rare, and therefore having a value greater than is due to their mere size. To provide for this, it is generally assumed that, above one. carat, the value shall increase as the square of the weight-i.e., that a stone double the weight of another shall have four times the value; treble the weight, nine times the value; ten times the weight, one hundred times the value, and so on.

The money value of diamonds is a difficult subject to touch upon, as a distinction must always be drawn between the retail price asked by jewellers from the public, and the real market price of the diamonds as sold by the dealers. Moreover, the value will always vary according to the state of the market, as well as according to the quality and cut of the stones.

As a

rough approximation, brilliants of firstrate quality, and perfect in every respect, may be estimated at about 127. per carat; reducible to half this, or even less, for stones of inferior water. According, therefore, to the rule of the weight above laid down, a diamond of half a carat might be estimated as worth 67.; but one of two carats would be worth 2 × 2 × 12 = 487; one of five carats 5 × 5 × 12 = 3001; and so on.1

1 Referring to the square or best form of brilliants, the solid content of a cut stone, of proper proportions, is about of that of the circumscribing parallelopipedon; and, taking the Sp. gr. at 35, we shall obtain the following rule. Let d side of the square, or breadth across the girdle, and t the thickness of the stone, from table to collet; both in tenths of an inch;-then

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In a well proportioned stone t should be

This rule will, however, hold only up to the limit of stones in ordinary sale. Such as are very large and of exceptional production cannot be valued by any rule; they are worth just what the state of the demand among crowned heads and millionaires will enable their holders to get for them.

The general value of diamonds has been rising of late years; for, though the production is not scanty, the demand, owing to general prosperity, and the extension of ornament to wider classes in society, is largely on the increase.

Imitations of diamonds are generally of one of the following three kinds :

1. White Topaz.-This is nearly as 'hard as diamond, and about the same specific gravity, and may therefore be mistaken for it when tried by these tests. A London jeweller died lately in the belief that a fine stone he had come into the possession of was a valuable diamond, and left large legacies to be paid out of the proceeds of its sale; but it proved, on examination, to be only a white topaz, and of very little value. The difference may be recognised by the optical qualities, which differ much in the two stones.

2. Rock Crystal (Brighton diamonds, Irish diamonds, &c.).-This substance, though hard enough to scratch glass, is much softer than diamond, and is easily scratched by it. It is also much inferior in brilliancy and in specific gravity.

3. Paste.-This, which is a glass prepared with metallic oxides, can be made equal to diamond in refractive power, and therefore can be given a great brilliancy; but it is very soft, softer even than common glass, and it does not retain its lustre.

There is also a method of deception sometimes practised by what is called half-brilliants; i. e. stones in the form

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or the value in £ 13 to 30, worth of stones varies, cæteris paribus, as the sixth power of their lineal dimensions. The height of the table above the girdle should be = } t. = t;-the depth of the collet below

of brilliants, in which the upper pyramid is a real diamond, and the lower a piece of some inferior stone, cemented to it; the whole being set so as to hide the junction. When this deception is suspected, the stone should be taken out of its setting for examination.

A very remarkable discovery has lately been made, that the chemical element boron, the base of the common substance borax, may, by a peculiar process, be obtained in transparent crystals which possess the high refractive power of the diamond, and a hardness as great, if not greater. At present, the crystals produced have been too small to be of commercial value; but it is quite possible that, hereafter, the discovery may prove to be of great importance.

It only remains to mention a few particular stones celebrated for their size, and which have had, on account of their great value, a history of their own.

The largest stone professing to be a diamond is the "Braganza" found in Brazil in 1741, and preserved, in its rough state, in the Royal Treasury at Lisbon. It is as large as a hen's egg, and weighs 1680 carats; but doubts are entertained whether it may not be in reality only a white topaz and no diamond at all; a supposition which, as the Portuguese Government decline to allow it to be cut or sufficiently examined, would appear quite possible.

The largest authenticated diamond known is that of the Rajah of Mattan in Borneo. It is of the purest water, of a pear shape, and weighs 367 carats. It was found a century ago at Landack, and has been the object of many wars for its possession.

The celebrated "Pitt" or "Regent" diamond was found in 1702, in the mines of Parteal, twenty miles from Masulipatam, by a slave, who having concealed its discovery from his employers, offered it to a sailor on condition that he would give him his freedom. The sailor lured him on board his ship, threw him overboard, and sold the stone to the then Governor of Fort St. George, whose name was Pitt, for 10007.; he

then hanged himself for remorse. The diamond was purchased from Pitt by the Regent of France, for 135,000l. It weighed 410 carats in its rough state, but was cut into a fine brilliant of 137 carats, thus losing two-thirds of its weight in the operation. It is said to be the finest diamond (though not the largest) in the world, in beauty of form, and purity of water. During the reign of terror, when the Tuileries were plundered, the diamond disappeared, along with all the other crown jewels; but it turned up again, and was pledged by the Republic to a merchant in Berlin. Redeemed at a later period, it embellished the sword of Napoleon I., and was taken by the Prussians after the battle of Waterloo. It is now in the French crown, and was exhibited in the French Exhibition of 1855.

The "Star of the South," another large brilliant, was also exhibited there: it was found lately in the Brazilian mines, and weighs 125 caráts; it is of an oval shape; 35 millimetres long, 29 wide, and 19 thick. It is very pure, but its colour is slightly inclining to pink. It is in private hands, and for sale.

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The "Sancy" diamond, of 53 carats, has a singular history. It came originally from India, and, about the fifteenth century, was in the possession of the luxurious Duke of Burgundy, Charles the Bold, who wore it, probably as a talisman, in the unfortunate battle of Nancy, in Switzerland, where he was killed. common Swiss soldier, who discovered the body in a ditch, found the jewel in the clothes, and, not knowing its value, sold it for a florin to a Swiss priest, who transferred it to the hands of the Confederacy. It subsequently came into the possession of the King of Portugal, who, in 1489, being in want of money, parted with it to a French trader. In the sixteenth century it found its way into the hands of a Huguenot nobleman, the Baron of Sancy, who happened to be in Soleure when King Henry III. was trying to negotiate a loan. Sancy offered him, as a true

accepted; but the messenger who was entrusted to convey it to the king (some accounts say Sancy himself) was waylaid and murdered, but had time before his death to swallow the stone, which subsequently was found in the stomach of the corpse. The stone was next traced into the possession of James II. of England, who took it with him when he fled to France in 1688, and afterwards, when he was in distress for money, parted with it to Louis XIV. for 25,000l. and Louis XV. is said to have worn it in the clasp of his hat at his coronation. It vanished in 1792, but reappeared in the Napoleon era, and was sold for 500,000 silver rubles to the Emperor of Russia, in whose possession it still remains.

The "Nassack" diamond was captured during the Mahratta war in India, in the Peishwa's baggage, by the combined armies under the Marquis of Hastings; and, after changing hands several times, was purchased, about twenty years ago, by the Marquis of Westminster. It was afterwards partly re-cut by Hunt and Roskell, and is now a beautiful colourless stone, weighing 785 carats. It is of a triangular or pear shape.

Many other large diamonds might be mentioned, each of which has a history, but perhaps the most interesting

of all, is our own great diamond, the celebrated Koh-i-noor; the story of which would make a very fair true romance of three goodly volumes.

Its origin is older than any historical records reveal, but it can be traced as far back as the beginning of the fourteenth century, when it came into the treasury of Delhi; and from this time it became intimately associated with the entire history of the Indian wars and dynasties, until, on the late annexation of the Punjab, it was taken possession of by our government, brought to England in 1850, and presented to the Queen. It was shown at the international exhibition of 1851, in the state it was received, weighing 186 carats; but it was so badly cut that its brilliancy scarcely exceeded that of a piece of crystal, and it had several flaws and defects in its structure. The Queen, after taking advice from competent judges, decided to have it recut; which was done in London (by workmen expressly brought over from Amsterdam for the purpose) in 1852. It has now the form of a regular brilliant; and, though its weight has been reduced to 101 carats, it has become, what it never was before, a most splendid jewel, worthy of its royal mistress, whose unsullied diadem may it long adorn!

A FEW WORDS ABOUT SORROW.
BY THE AUTHOR OF "JOHN HALIFAX, GENTLEMAN."

OF which it is rather venturesome to
say anything in this Democritan age,
that boasts such a surplus of laugh-
ing philosophers. Our forefathers sen-
timentalised over their feelings

we

are somewhat ashamed of having any; they made the most of afflictions, real and imaginary-we are often disposed to turn grief itself into an excellent joke. A "broken heart" is a stock subject for humour; yet some have known it; and few even of the worthiest of us have not

making a jest about funerals, just as if there were no such thing as dying. It is good to laugh, it is good to be merry; no human being is the better for always contemplating "the miseries of human life," and talking of "graves and worms and epitaphs." Yet since sorrow, in its infinitely varied forms and solemn inward unity, is common to all, should we not sometimes pause to look at it, seriously, calmly, nor be afraid to speak of it, as a great fact-the only fact of

of? And since we are so sure of it, will a few words more or less, suggesting how to deal with it in others, and how to bear it for ourselves, do us any harm? I trow not.

For, laugh as we may, there is such a thing as sorrow; most people at some portion of their lives have experienced it-no imaginary misery-no carefully petted-up wrong; no accidental anxiety, or state of nervous irritable discontent, but a deep, abiding, inevitable sorrow. It may have come slowly or suddenly; may weigh heavier or lighter at different times, or according to our differing moods and temperaments; but it is there a settled reality not to be escaped from. At bed and board, in work or play, alone and in company, it keeps to us, as close as our shadow, and as certainly following. And so we know it will remain with us; for months, for years-perhaps even to the other world.

Therefore what can we preach to ourselves, or to our fellows, concerning it? Perhaps the wisest lesson of all is that of the ancient Hebrew, who laid his hand upon his mouth, "because THOU didst it." For sorrow is a holy thing. The meanest mortal who can say truly,

"Here I and sorrow sit,"

feels also somewhat of the silent consecration of that awful companionship, which may well

"Bid kings come bow to it,"

yet elevates the sufferer himself to a higher condition of humanity, and brings him nearer to the presence of the King of kings.

Grief is a softening thing, from its very universality. Ex uno disce omnes. Your child, my neighbour, may be dying, or giving you anguish sharp as death; my own familiar friend may have lifted up his heel against me, causing me now, and perhaps for ever, to doubt if there be such a thing as fidelity, or honour, or honesty in the world; a third, whom we all know and meet daily, may have received yesterday, or last week, or last month, some

and bleeding inwardly, yet which may prove a death wound; a fourth has sustained some heavy visible blow or loss, which we all talk of, compassionate, would fain comfort if we could, but we cannot. These various shapes which sorrow takes compose a common unity; and every heart which has once known its own bitterness, learns from thence to understand, in a measure, the bitterness of every other human heart. The words, "He bore our griefs and carried our sorrows," "in all our afflictions he was afflicted," have a secondary and earthly as well as a Divine significance; and to be "acquainted with grief," gives to any man a power of consolation, which seems to come direct through him from the great Comforter of all. The "Christus Consolator" which Scheffer painted,-the Man Divine, surrounded by, and relieving every form of human anguish, is a noble type of this power, to attain which all must feel that their own anguish has been cheaply purchased, if by means of it they may have learned to minister unto all these.

This ministry of consolation is not necessarily external, or intentional. We must all have sometimes felt, that the people who do us most good are those who are absolutely unaware of doing it. Even as "baby-fingers, waxen touches," will melt into flesh and blood again a heart that has seemed slowly turning into stone, so the chance influence of something or somebody, intrinsically and unconsciously good, will often soothe us like a waft of sweet scent borne across a dull high-road from over a garden wall. It may be the sight of peaceful, lovely, beloved old age, which says silently and smilingly, "And yet I have suffered too;" or the brightness in some young face, honest and brave, which reminds a man of the days of his own youth, and shames him out of irresolution or cynical unbelief, daring him, as it were, to be such a coward as to let his after life give the lie to the aspirations of his prime. Or the influence, more fugitive still, comes from a word or two in a

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