The French ‘paste’ which imitates the diamond so closely is a peculiar kind of glass, the manufacture of which was brought to a great degree of perfection some fifty years ago by Donault-Wieland of Paris. The finest quality of paste demands extreme care in the choice of materials and in melting, &c. The basis of it, in the hands of the expert manufacturer just named, was powdered rock-crystal or quartz. The proportions he took were—six ounces of rock-crystal; nine ounces two drams of red-lead; three ounces three drams of pure carbonate of potash; three drams of boracic acid; and six grains of white arsenic. The product thus manufactured was extremely beautiful, but rather expensive, compared with the prices now charged for artificial jewels. It has never been surpassed in brilliancy. But of late years the greater purity of the potash and lead oxide used, and the improvements in the furnaces and methods of heating them, have all tended to reduce the price of the ‘diamonds’ thus manufactured. THE MISSING CLUE. CHAPTER V.—THE COLONEL’S DAUGHTER. Meanwhile, the subject of the previous conversation is seated in a private room before a merry crackling fire, small reflections of which lurk here and there in the dark polished oak with which the walls are panelled. Everything in the apartment has an extremely comfortable appearance save its living occupant, and his features wear an expression totally at variance with his surroundings. He is twisting a crumpled note between his fingers; while, judging from the expression with which he regards it, his feelings can scarcely be of an agreeable nature. The offending epistle is written in a bold decided hand, which harmonises well with the short and haughty tenor of its contents. As a perusal of this may enable the reader more clearly to understand the ensuing narrative, a copy is here inserted: Colonel Thorpe presents his compliments to Lieutenant Ainslie, and in reply to that gentleman’s letter of this morning, begs to state that any overtures from him relating to Miss Thorpe will receive an absolute negative. It is also requested that Lieut. A. will discontinue his visits to Coombe Hall, as Col. T. wishes him distinctly to understand that this decision is final. _Dec. 22, 1760._ The exasperated recipient of this ungracious piece of writing makes a movement as if to consign it to the hungry blaze which is roaring up the chimney; but checking himself ere the action is performed, he places the missive in a side-pocket, and falling back in his chair, resigns himself to a long train of unenviable reflections. * * * * *