perceptible, but of the intense reddish color produced by the soda. If the admixture of the soda salt amounts to several per cent., the reaction of potash will be entirely suppressed, and the coloring of soda alone will be observable. The reaction of potash is also prevented, when the substance contains a lithioniferous salt in a quantity not very minute. For the reaction of some potash salts on charcoal, see No. IV. Silicates, which contain a considerable quantity of potash, produce a distinct violet color in the external flame only in those cases, when they are perfectly free from soda or lithion and are moderately fusible at the edge.

c. RED. There are three substances which give a red color to the outer blow-pipe flame, viz., lithion, strontia, and lime. The red is carmine. a. Lithion and its salts, when fused on a platina wire, in the point of the blue flame, give a very fine and decided carmine color to the external flame. Chloride of lithium colors most intensely. Considerable admixtures of potash-salts do not prevent this reaction. A shade of violet is the utmost that may be perceptible. Small adulterations of a soda salt are however capable of converting the carmine into a yellowish red. If more of the soda salt is present, a decided reddish yellow appears, which is scarcely distinguishable from the pure soda coloring. For the characteristics of lithion-salts, see No. IV. Many lithioniferous minerals, when fused in the forceps with the point of the blue flame, produce a red coloring in the outer flame. The Mica of Altenburg and Zinnwald especially belongs to this class, as it colors the external flame very intensely. This color diminishes, however, as soon as the scale has been fused to such an extent, that it is difficult to protract its fluidity by means of the blow-pipe flame. There are some minerals which present other colorings conjointly with the red one of lithion, and indeed in such a manner, that both colors may either appear separated or mixed. If, for instance, a small quantity of pulverized Triphyl line (phosphates of lithion, iron and manganese), is treated in the eye of the platina wire with the extremity of the blue flame, a carmine-colored streak, caused by the lithion, is perceptible in the external flame, while this is surrounded by a green one, originating from the phosphoric acid (see further on). It is difficult to observe this in the forceps on account of the great fusibility of the triphylline. Were we to treat the Amblygonite from Cursdorf, whose chief contents are phosphates of lithion and alumina, in the forceps by. means of the point of the blue flame, we would perceive within the outer flame a yellowish-red cone, surrounded by one of a reddishyellow color produced by an adulteration of soda. This coloring continues as long as the molten part retains its fluidity. Lithioniferous silicates, which would not, of their own accord, present the red coloring of the outer flame, exhibit this, according to Turner, if we mix in some fluor-spar and bi-sulphate of potash, and then treat it by means of the blue flame upon the platina wire, as is

the case with the regular test for lithion (see further on). B. Strontia.-Chloride of strontium, when fused upon the platina wire in the blue flame, instantly produces an intense red in the outer flame. Many other combinations of strontia, as for instance the carbonate (strontianite) and sulphate (coelestine), when exposed to the blue flame upon the forceps, color the outer flame at first slightly yellowish, but afterwards carmine. The presence of baryta destroys the reaction of strontia. y. Lime.-Chloride of calcium colors the external flame red, but not so intensely as chloride of strontium. Most pure carbonates of lime and compact lime rocks produce at first a slightly yellow color in the outer flame. When the carbonic acid is discharged, however, a red color, though less intense than that of strontia, is produced. The presence of baryta suppresses this reaction, but to this we shall return when speaking of baryta. Fluor-spar, while fusing, colors the outer flame as red as does pure calc-spar. Gypsum and anhydrite produce at first merely a slight yellow color, but afterwards a subdued red. Phosphate and borate of lime produce a green color and not a red one. Tafelspath is the only one of the silicates which produces the correct, slightly red color of lime in the outer flame.

d. GREEN.-There are six substances which produce a green coloring of the extermal blow-pipe flame. These are baryta, molybdic acid, peroxide of copper, telluric acid, phosphoric acid, and boric acid. a. Baryta.-Chloride of barium, when fused on a platina wire with the extremity of the blue flame, colors the outer flame green. At first a pale green is produced, but afterwards an intense yellowish-green. We can best observe this color, if we use but a small quantity of this salt. Carbonate of baryta (witherite), and sulphate of baryta (heavy-spar), when treated with the point of the blue flame upon the forceps, also give a yellowish-green tint to the outer flame, though not so intensely as chloride of barium. The presence of lime does not prevent this reaction, and an illustration may be found in the baryto-calcite, which consists of the carbonates of baryta and lime. This mineral produces a yellowish-green color in the outer flame, but continued blowing will occasionally produce a slight red at the extremity of the coal. B. Molybdic acid, or oxide of molybdenum, when attached to the moistened eye of the platina wire and heated with the point of the blue flame, colors the external flame yellowish-green, very much like baryta, while molybdic acid is volatilized. Were we to heat a thin scale of natural sulphate of molybdenum (molybdaenglanz), held in the forceps, with the point of the blue flame acting upon its sharp edge, we would, without producing fusion, instantly color the outer flame yellowish-green by means of the molybdic acid formed. y. Peroxide of copper, either alone or in its combination with some acids, which do not of themselves produce any color,

gives an emerald hue to the outer flame. Amongst these we have the carbonate, acetate, nitrate and sulphate of copper. Metallic copper, when treated on the charcoal with the blow-pipe flame, if it is not entirely protected from the access of atmospheric air, becomes superficially oxidized, and colors the outer flame in the same manner. The combination of copper with iodine also causes a very intense emerald green in the outer flame. Cupriferous lead ores color the centre of the external flame blue from lead (see farther on), and in the outer cone, particularly towards the extremity, emerald green. Cupriferous silicates, when heated by the blue flame in the platina forceps, give the outer flame occasionally a very intense emerald green, viz., emerald copper and silicate of copper. The same coloring also takes place, when oxide of copper forms an essential and the only coloring ingredient, as for instance in calaite. 8. Telluric acid, if attached to the moistened eye of the platina wire and heated in the blue flame, melts, fumes and colors the outer flame green. If the telluric acid, sublimed after the treatment of an ore of tellurium on charcoal, is blown upon with the blue flame, it disappears with a green tint, and, if selenium be present, with a bluish-green one. e. Phosphoric acid.-According to Fuchs and Erdmann, phosphoric acid, phosphates and minerals containing phosphoric acid, partly alone, partly moistened by sulphuric acid, produce a bluish-green coloring of the outer flame. This reaction is so definite, that even small quantities of phosphoric acid may be discovered in minerals, when these are pulverized, moistened with sulphuric acid, and introduced as a paste into the eye of the platina wire and then heated with the point of the blue flame. The same may be said of salts, which from the amount of soda or any other coloring admixture that they contain, might not, if treated alone, exhibit the presence of phosphoric acid. If the salts contain water, this must first be removed by roasting or fusing a small test upon charcoal with the aid of the blow-pipe flame. After this, the calcined test should be pulverized, moistened with sulphuric acid, and exposed to the blue flame upon the platina wire. Should such a salt contain soda, we will at first notice a distinct bluish-green coloring of the external flame, caused by the disengaging of the phosphoric acid by the sulphu ric, though this is colored by an intense reddish yellow, caused by the soda. Since the bluish-green coloring lasts but a short time, we must observe very attentively whether the outer flame is really bluish-green or not, when we bring the test in contact with the blue flame. Phosphate of lead, as well as green and brown lead ores, if treated alone, color the outer part of the flame green, which is internally blue from the oxide of lead. . Boric acid, natural or artificial, colors the outer flame greenish-yellow, when fused in the eye of the platina wire with the point of the blue flame. If this acid, however, is not quite free from soda, the

If

green color of the outer flame will be more or less mixed with yellow. Borax, when treated alone, does not produce a green color, but, on account of its contents of soda, a yellowish one. this salt, after having been fused to remove its water and then pulverized and moistened with sulphuric acid, be exposed to the point of the blue flame, an intensely green coloring will be produced for a short time. This will be changed into a yellow one as soon as the salt is decomposed and no more free sulphuric acid is present. Almost all minerals containing boracic acid, when pulverized, moistened with sulphuric acid, and exposed to the blue flame in the eye of the platina wire, produce a green coloring in the outer cone. Another, and indeed a very safe method for discovering boric acid in minerals by the greenish-yellow coloring of the outer cone, has been proposed by Turner (see further on).

e. BLUE.-There are some substances which color the outer flame blue, when heated or molten in the blue flame. They are the following: arsenic, antimony, lead, selenium, and the combinations of copper with chlorine and bromine. a. Arsenic. Metallic arsenic and those metalliferous arsenurets, which themselves would produce no coloring in the outer flame, as e. g. red nickel ore and arsenuret of cobalt, are surrounded by a light blue shine when heated upon charcoal by means of the blue flame. If the sublimate, produced upon the charcoal by this process, and which is arsenious acid, and hence is very volatile, be blown upon by the blue flame, it will be observed to disappear with a very distinct light blue brilliancy. Arseniates, whose bases do not produce a color in the external flame, as e. g. arseniates of nickel and cobalt, ironsinter, when exposed to the point of the blue flame in the forceps, give an intense light blue color to the outer flame. In many cases a blue coloring even then takes place, when the base would produce a coloring of its own, as arseniate of lime (Pharmakalith). B. Antimony, in its metallic state, when fused upon charcoal within the blue flame, produces a barely perceptible blue brilliancy round the molten globule. The white sublimate of oxide of antimony thus produced, when blown upon by the blue flame, disappears with a greenish blue brilliancy. y. Lead. If we fuse metallic lead on charcoal within the blue flame, the molten metallic button will be surrounded with a sky-blue brilliancy, while oxide of lead will be sublimed on the charcoal. By heating this sublimate with the blue flame, it may be driven from place to place with the production of a skyblue brilliancy. Salts of lead, whose acids do not cause an intense color of the external flame, when treated upon the platina wire or in the forceps with the point of the flame, give an intense azure-blue color to the outer flame. 8. Selenium, when fused upon charcoal within the blue flame, is volatilized with the appearance of a deep blue brilliancy, and the same may be

said of the sublimate of selenium on charcoal. e. Chloride of Copper, both natural and artificial, when heated strongly upon the platina wire with the blue flame, colors the external flame intensely blue, but afterwards green from the oxide of copper formed. . Bromide of Copper, treated in the same manner as the chloride, colors the outer flame at first greenish-blue, and afterwards green from the oxide of copper formed.

[To be continued.]

ART. IV. THE GREAT SILVER LEAD MINE, SHELBURNE, NEW HAMPSHIRE. BY CHAS. S. RICHARDSON, CIVIL AND MINING Engineer. UNLIKE most mines in the primitive mountain districts, this possesses a secretiveness unusual to those of England and Wales. This peculiar feature in the minerals in this section of country, is one great cause why the lodes as yet have not been publicly known. It is common where champion lodes occur, that they throw to the surface either a gozzan, or some distinct traces of sparry veins, or as is most generally the case, the country in their immediate vicinity is in a decomposed and discolored state; denudation frequently leads to important discoveries, and in the instance now before us, what has been developed may be attributed solely to this cause.

The history of the Shelburne mine, the rich ore the former company raised, and the why and the wherefore they did not succeed in making the adventure remunerative, is quite unnecessary for me to detail; the object of this report is to give an accurate statement of my views on the estate as a mineral property as it now stands, with such suggestions as I may deem necessary to make, relative to its again being worked for its minerals. The mine is situated about the north-west corner of the set, which contains above twenty thousand acres of mountain forest land. The greatest part of it is in its primeval state. At the site and near the present mine, are three large lodes now discovered, which we will denominate as the north lode, middle lode, and south lode; more appropriate names may be given them hereafter. All these are in "Mount Argent," (the name now given to this mountain from its being so very rich in silver)-a small mountain about 650 feet above the valley of the Androscoggin River. The stratum is gneiss, granite, mica, slate, hornblendic slate, quartz rock, green porphyry or mountain greenstone, called in Scotland whinstone, with small bands or veins of trap. The cleavage planes are the same here as in the States of New York, Massachusetts and Vermont, viz., about 25° north-east. There is no regular bearing or dip in the stratified rocks, they may however be averaged at about 55° north-west, and when not influ VOL. III.-33