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• The direction in which the stone is to be cut being determined on, the artist must be well aware which are the hard points, and which the soft ones ; the former being those solid angles of the original octohedron, which it is necessary to cut directly across, and the latter, those solid angles which are to be obliquely divided.
• The Diamond is imbedded in strong cement, fixed at the end of a stout spindle-shaped-stick about a foot long, with that portion only projecting, the removal of which is to form the first facet. The in. strument einployed for this purpose is another Diamond fixed in a stick similar to the former, with one of the solid angles projecting. In order to collect the powder and shivers that are detached during the process, the cutting is performed over a box, with two upright iron
pegs fixed on the sides, for the workman to support and steady his fingers against, while with a short repeated stroke somewhat be. tween scratching and cutting, he is splitting off or more laboriously wearing away the Diamond in that part where the facet is to be placed. This being done, the cement is softened by warming it, and the position of the Diamond is changed, in order to bring a fresh part under the action of the cutting Diamond. When in this slow and laborious way all the facets have been placed upon the surface of the Diamond, the cutting is completed.
The next object is to polish the facets, and at the same time to redress any little inequalities that may have taken place in the cutting. The polishing mill is an extremely simple machine, consisting of a circular horizontal plate of cast iron 14 or 15 inches in diameter (called a skive), suspended on a spindle, and capable of being put into rapid motion by means of a larger wheel. In order to keep the Diamond perfectly steady while the polishing of each facet is going on, the following contrivance is had recourse to. A copper cup (called a dopp:) about three quarters of an inch in depth and in width, and furnished with a stem about four inches long of stout copper wire, is filled with plumbers' solder, which also projects in a conical form beyond the rini of the cup: in the apex of this cone, the solder being softened by heat, the Diamond is imbedded with one of the facets projecting, The stem of the cup is now put into very powerful pincers. The handles of the pincers (called tongs) are of wood, are broad and terminated by two feet, about an inch high, so that when laid horizontally they are supported exactly as a pair of candle snuffers is, the studs fixed to the handles of the snuffers representing the leg of the pincers, and the single stud near the point of the snuffers representing the inverted copper cup holding the Diamond, and at the same time having its stem strongly griped by the pincers. In this position the Diamond is placed on the plate, the pincers resting on their legs on the wooden bench or table that supports the plate, and pressing at the same time against an upright iron peg: the broad part of the pincers between the legs and the Diamond, is then loaded with weights, both to steady the machine, and to increase the pressure of the Diamond against the skive. Matters being thus adjusted, a little oil and Diamond powder is dropped on the plate, it is set in motion at the rate of about 200 revolutions in a minute, and the process of grinding down, and at the same time of polishing is begun.
The Diamond is taken up and examined from time to time, and is adjusted so as to give the facet its true form. There is room on the skive for three or four Diamonds at the same time;. and to give each its proper share of attention is as much as one person can well manage. The completion of a single facet often occupies some hours' pp. 47–56.
Other gems are brought into the shape required merely by application to the mill, without the tedious process of cutting down by hand, but the skive is of copper or tin, charged with diamond powder and oil, and the last polish is given on a plate of brass with tripoli and rotten stone.
The latter part of Mr. Mawe's work gives an account of the Ruby, Sapphire, Emerald, Topaz, Amethyst, Chrysoberyl, Chrysolite, Aquamarine, Tourmaline, Hyacinth, and Jargoon, with notices respecting the inferior stones made use of in jewellery. The descriptions are drawn up in reference to their application tu articles of luxury, rather than to their properties as minerals, but are correct and intelligible.
Though much too superficial for a scientific performance, this essay appears not badly calculated to excite curiosity and diffuse some information respecting these costly trifles among that class of persons on whom their sale must principally depend; to most of whom a dull hook would be an infinitely greater evil than ignorance. It is concise, entertaining, and well printed, and will we hope increase Mr. Mawe's celebrity as a dealer in minerals, if it does not materially raise his credit as a scientific writer.
Art. XII. The Giaour : a Fragment of a Turkish Tale. By Lord
Byron. Sixth Edition. 8vo. pp. 66. Murray. 1813. A Tale of more high-wrought terror than this is not often to
be found :-a tale of terrible passions, giving birth to terrible deeds,-and told in that broken and mysterious manner,
where more is meant than meets the ear,' where the poetry, like the glare of lightning on a dark night, just serves to shew, and to exaggerate, the darkness around. To tell the story in any way, but that in which the poet has told it, is doing it wrong, and yet we must give a slight sketch of it, that our readers may be able to understand our quotations.
The beautiful Leila was the favourite slave in the serai' of Hassan, but she yielded to the temptations of the 'Giaour,' (or infidel,) and betrayed her faith. The inhuman Hassan fástens the lovely false one in a sack, takes her out to sea, and drowns her. Shortly after, he sets out'to woo another bride, but is met by a band of Arnauts,' with the Giaour at their head; end but one of his company
is spared to bear the tidings to the Ss 2
mother of his intended bride. Afterwards, we find the Giaour in a monastery, and the poem ends with his dying confession.
On this bold outline Lord Byron, (as will be easily believed by those of our readers who are acquaiated with Childe Haroid,) has laid the strongest and most brilliant colouring. The poet sees every thing himself, and so rouzes the feelings and enthusiasm of the reader, that he seems to see it too. The first picture is of the Giaour on the night of Leila's murder.
• On-on he hastened—and he drew
And sternly shook his hand on high,
is won—no more is seen
Wue without name—or hope-or end.' p. 14.
'Tis he~'tis he-I know him now,
I know him by his jet black barb,
Though now array'd in Arnaut garb,
• Lost Leila's love-accursed Giaour!. pp. 33, 34. At length the poet sees him in the monastery.
• How name ye yon lone Caloyer?
· His features I have scann'd before
Since, dashing by the lonely shore,
It breathes the same dark spirit now,
« 'Tis twice three years at summer tide
• Since first among our freres he came ;
. For some dark deed he will not name.
44. In the next passage, and it is a fearful one,) we think that our readers cannot but recognize the portrait of Childe Harold. Lord B. bas disclaimed, the character; but that he possesses the power of assuming it, during the hour of inspiration, no one can well doubt. Mr. Burke says, that he could never put on any particular expression of countenance, but he felt, for the time, the corresponding passion. Nor can we believe that any one could write the following lines, without entering, while writing them, with peculiar energy, into the feelings they describe.
• Father! thy days have pass'd in peace,
'Mid counted beads, and countless prayer;
Thyself without a crime or care,
My days, though few, have pass'd below
. And I shall sleep without the dream
• Dark as to thee my deeds may seem.' pp. 49, 50.