purpose, a strong platinum wire, three inches and a half in length, Fig. 28. C C B will be found applicable. On the end of the platinum wire, a ring-Fig. 28—▲, is made, by means of the small forceps before described, and the touching point, 1, is curved to an obtuse angle: then, into the charcoal holder previously described, a charcoal prism, of a corresponding size, is inserted so that its upper side nearly reaches the cavity, i, When of the instrument, Fig. 27. this is accomplished, a depression is made on its surface, and the platinum wire is sunk so accurately into it that the charcoal appears to touch it uniformly in all parts. The straight part of the wire is now bent so as to follow the lines m n k-Fig 27. To the curved part of the wire, a hollow thin platinum foil, c, Fig. 28, 9-16ths of an inch in breadth, is united, as depicted in the figure. 12. A CAPSULE OF BRASS FOIL, with the interior polished, two inches and a half in length, and of the form of Fig. 29. It is used for mixing silver and gold ores with proof lead and calcined borax; and for pouring these, or similar mingled ingredients, into a cornet of soda paper. Fig. 29. 13. A SMALL SCISSORS, suffi ciently strong for cutting metallic lamina, as well as soft materials. 14. A KNIFE. For many researches, a steel knife, well sharpened and magnetized, is requisite. It is employed for mixing the various fluxes in quantitative assays, and also for determining the degree of hardness of many metallic bodies. 15. Some FILES, of different sizes and fineness, three-edged, flat, half-round, and round, the description of which is unnecessary, are required in many examinations. 16. AN IRON INSTRUMENT for the formation of CUPELS; with a Bolt and Stand.-Small Cupels of bone-ashes, are necessary for refining plombiferous alloys obtained in quantitative assayings, containing Silver or Gold. Cupellation is resorted to for the purpose of separating the noble metals as they are called, from those which are readily convertible into oxides. The operation consists in fusing the alloy on charcoal with pure lead, and then heating the resulting bead in the oxidating flame, upon a substance sufficiently porous to absorb the fused oxides produced by the ignition. The best method for the preparation of these Cupels is to cast them in a metallic mould; in which they are to remain till the cupellation is completed. Generally, two Moulds are employed, with concave depressions of different sizes, for the formation of cupels in large and small operations. Fig. 30, A, B, presents these moulds, as well as their bolts, a, b. The Moulds are of iron, and, in the Fig. 30. A B O Fig. 31. upper part, are 13-16ths of an inch in diameter; the bolts are of hardened steel, partly ground, and of a circular form. In the under part of each mould, cruciform grooves are usually filed, so that when one arm of a pincers is inserted, and the other pressed against the upper part of the mould, it may easily be removed, even when heated to redness. Fig. 31 is a small wooden stand, 31 inches in height, having on the under part a round piece of wood, serving as a durable support. In the upper part is a strong brass wire, fastened by a screw; and at the end of this wire is a brass cross, the arms elevated to an angle of 85°, so as to allow the mould to be conveniently placed between them. When the transverse incisions in the bottom of the iron instrument are not brought into contact with the arms of the brass cross, an operator is enabled to raise or depress the instrument at pleasure, so as to afford the required heat. 17. AN IVORY SPOON, well polished and ground, Fig. 32. 5-16ths of an inch in breadth, and of the form given in Fig. 32. The handle of this spoon, which is in the form of a spatula, is for mixing in the capsule ores with pure lead and calcined borax; and the spoon part is necessary in the weighing of ores and such substances as are to be fused. 18. A SMALL BRUSH.-For quantitative examinations a painter's brush is indispensable, for detaching from the pans of the balance any remaining powder, et cetera. Fig. 33. 19. A LEAD SIEVE.-In Blowpipe analysis, the Lead must be in a very minute state of division, to allow of its being intimately mixed with the various substances to be operated upon. It may be obtained in this state by agitating granulated lead in a small brass sieve-Fig. 33. The method of assaying is so very delicate, that it almost always produces a bead of silver, when the common lead of commerce is submitted to trial. It is for this reason that so much care must be taken in preparing lead for cupellation. The best method for obtaining it pure, and in a very minute state of division, is to precipitate it from a solution of the acetate, with a plate of zinc. 20. A STEEL MAGNET.-A strongly magnetized steel blade, or a steel magnet, about three inches and a half long, and of an inch in diameter, will be useful in ascertaining whether small particles of the ores under examination are magnetic. If, to a mixture of finely divided iron and tin, immersed in water, the end of the magnet be applied, the particles of iron will be found adhering when it is withdrawn. 21. A LEAD MEASURE.-The instrument-Fig. 34-which is similar to a gunpowder-measure, is for avoiding the weighing of a certain portion of lead, in quantitative assayings. It Fig. 34. consists of a glass tube, open at the extremities, containing a small wooden cylinder. This glass tube is divided into parts of equal degrees, 10, 15, 20, each of which are capable of holding 100 milligrammes of granulated lead. For quantities less than 100 milligrammes, the piston is graduated as in the figure, with 1, 10, 2, 3, 4, 5, 20, 30, 40, 50 milligrammes corresponding to 22. A SMALL WOODEN CYLINDER.—a cylinder of wood is employed to make small cornets from the soda-paper described at page 19. It should be about 9-32nds of B A Fig. 35. an inch in thickness, as in Fig. 35, B; and, for convenience, should have a handle at one end. The cornet is made in the following manner :-A slip of paper, A, is so placed under the cylinder that one of its long sides. projects beyond the upper end of B, as in the figure, a space equal to the diameter of the cylinder. The part of the paper so protruding is then folded back on B, with the aid of a small spoon; the part of the paper to the left of B is next folded over the cylinder, turned in such a manner that the remaining portion of the paper to the right of B, is folded over the latter, and the closed end struck upon a hard even surface, in order that the cornet may retain its shape, after the removal of the cylinder. 23. A POLISHED IRON SPATULA, four inches in length, and of the form of Fig. 36, is employed in levigating such alligations as are to be roasted in quantitative determinations. Fig. 36. 24. TEST-TUBES, with a Funnel and Stand.-When compounds, which contain several heterogeneous ingredients, cannot be accurately recognised in the Blowpipe flame, an operator must resort to liquid testing, to ascertain each constituent, either qualitatively, or quantitatively. This is effected by means of testtubes, Fig. 37, five and a half inches long, and five-eighths of an Fig. 37. Fig. 38. clear solution. inch in diameter, which are The Funnel, Fig. 38, is for the reception of a paper filter, into which the turbid liquid is poured from a test-tube, to separate the precipitate produced by a reagent, from the 25. A small Glass PIPETTE.-This instrument should be five inches in length, and three eighths of an inch in diameter, Fig. 39. It is exceedingly convenient for affusing precipitates Fig. 39. with hot water; and also for withdrawing the supernatant liquor from the precipitate, in quantitative Gold and Tin analysis. The point only should be slightly contracted, and not drawn out into a capillary tube. 26. AN EDULCORATOR.-The Edulcorator, or, as it is generally termed, the wash-bottle,-Fig. 40,-is a German glass flask, capable of holding about a pint of water, the mouth of which is |