Chapter 6

+---------------------+---------------------------------- SUBSTANCE | IMPURITIES | TESTS. | POSSIBLY PRESENT. | ------------------+---------------------+---------------------------------- Ammonia, | Carbonic acid | Renders lime-water milky. NH_{3} | | Molec. Wt. 17 | Dissolved solid | Residue left on evaporation. | matter | | | | Chlorides | After acidulating with nitric acid, | | it gives a precipitate with silver | | nitrate, which after washing is | | readily soluble in ammonia and | | reprecipitated by nitric acid. | | | Sulphates | After acidulating with nitric acid, | | it gives a precipitate with | | barium nitrate. | | | Lime | A white precipitate with oxalate | | of ammonium. | | | Lead is often | Black precipitate with sulphureted | present, derived | hydrogen. | from the action | | upon flint glass | | bottles | | | Nitric acid. | Traces of | After dilution it gives a H, NO_{3} | sulphuric acid | precipitate with barium nitrate. Molec. Wt. 63 | | | Chlorides | After dilution it gives a | | precipitate with silver nitrate. | | | Peroxide of nitrogen| The acid is yellow. | | | Iodine may be | After dilution and cooling it gives | present if the acid | a blue color with starch, paste, | be prepared from | or mucilage. | sodium nitrate | | | Hydrochloric | Free chlorine | Liberates iodine from solution acid, HCl | | of potassium iodide. See also Molec. Wt. 36.5 | | "Chlorides," nitric acid. | | | Sulphuric acid | As above for nitric acid. | | | Perchloride of iron | Yellow color. Brown precipitate | | with ammonia added till it | | smells slightly. | | Sulphuric acid, | Bisulphate of | Residue on evaporation. H_{2}SO_{4} | potassium | Molec. Wt. 98 | | | Sulphate of lead | Milkiness on dilution. May be | | completely freed from lead by | | diluting with three or four times | | as much water, and allowing | | to settle. | | Acetic acid | Water | Does not solidify when cooled (glacial), | | to 17° C. (53º F.) H C_{2}H_{3}O_{2} | | Molec. Wt. 60 | Sulphurous and | White precipitates with silver | hydrochloric | nitrate. | acids | | | | Aldehyde, or | Blackens in the light after adding | volatile tarry | silver nitrate. | matter | | | | Organic sulphuric | Smell of garlic. | acid | | | Citric acid, | Tartaric acid | Strong solution of potassium. H_{3}C_{6} | | Acetate added to a strong solution H_{5}O_{7}H_{2}O | | of the acid will deposit white Molec. Wt. 210 | | crystalline bitartrate. | | Pyrogallic acid | Metagallic acid | Black residue, insoluble in water. (C_{6}H_{3})HO_{3}| | Molec. Wt. 126 | | | | Silver nitrate, | Free nitric acid | Reddens litmus paper. (Neutral AgNO_{3} | | silver nitrate does not Molec. Wt. 170 | | affect litmus.) | | Potassium | Chlorides and | Same as for ammonia. carbonate | sulphates | K_{2}CO_{3} | | Molec. Wt. 138 | | | | Potassium | Potassium carbonate| A strong solution is alkaline to iodide, KI | | test paper. Molec. Wt. 166 | | | Sulphates and | Same as for ammonia. | chlorides | | | | Potassium iodate | A pretty strong solution becomes | | yellow from liberation of iodine | | on addition of dilute sulphuric | | acid or, better, a strong solution | | of citric acid. | | Potassium | Similar to | See potassium iodide. bromide, KBr | potassium iodide | Molec. Wt. 119 | | | | Sodium carbonate, | Chlorides and | Same as for ammonia. Na_{2}CO_{3} | sulphates | Molec. Wt. 106 | | | | Sodium chloride, | Chloride of calcium | Oxalate of ammonium (after NaCl | Chloride of | addition of a little acetic acid) Molec. Wt. 58.5 | magnesium | gives a milkiness, or precipitate, | | indicating calcium; filter this | | out and add ammonia, chloride of | | ammonium, and phosphate of sodium | | (clear solutions). A precipitate | | indicates magnesium. Both the above | | cause dampness in wet weather. | | | Sodium sulphate | As for "sulphates" in ammonia. | | Potassium | Potassium carbonate | Effervescence with dilute acids, cyanide, KCN | nearly always | giving off a gas carbonic Molec. Wt. 65, | present | anhydride, which renders and hydrate, KHO | | lime-water turbid. Molec. Wt. 56 | | Kaolin | Chalk | Effervescence with dilute acids. | | Water, | Sulphates and | Same as for ammonia. H_{2}O | chlorides | Molec. Wt. 18 | | | Calcium carbonate, | Deposited by boiling. Test as | temporary hardness | for calcium chloride. See | | sodium chloride. | | | Ammonia, almost | Brown coloration, or | always present in | precipitate with Nessler's | distilled and rain | reagent. | water | | | Gelatine | Alum | Ash, sometimes as much as ten | | per cent. | | | Fatty matter | Separated by precipitation with | | alcohol. Dissolved out by ether | | or benzine, and left as a residue | | on evaporation of the solvent. | | | | Ammonium bromide | Potassium bro- | Leaves a residue when heated. (NH_{4})Br | mide or other | Molec. Wt. 98 | non-volatile | | bodies | | | | Ammonium chloride | Same as for chlorides in | | ammonia. | | Pyrogallic acid | Powdered glass | Left behind on solution. | | Potassium iodide | Potassium bromide | The crystals of bromide are | | usually more transparent than | | those of iodide, but no reliance | | can be placed on this. | | Silver nitrate | Potassium nitrate, | Will not yield the full quantity | sometimes present | of chloride on precipitation | in the fused | with HCl. Gives a purple color to | sticks--not in | flame. | the crystals | | | Sulphuric acid | When vended as pure,| No easy test can be given, as the | it invariably | substances are so numerous some of | contains a trace of | them volatile, and most require | iron. Common acid is| separation from the acid before | also liable to | detection. | contain arsenic, | | selenium, thalium, | | and many other | | substances. | | | | Organic matter, as | Gives a brown color to the acid. | a piece of straw | | in a carboy of acid | | | Hydrochloric acid | Arsenic | Marsh's test. | | | Some yellow samples | Reinsh's test; a small piece of | contain no iron, | copper foil becomes coated | but an organic salt,| on boiling in dilute acid. | and give an alkaline| | ash on ignition of | | the residue after | | evaporation | | | Calcium chloride | Calcium hydrate | The clear filtered solution made | | with distilled water is alkaline | | to test paper, and gives a | | precipitate on breathing into it | | through a tube. | | Pure (?) chemicals| Broken glass, bits | These impurities either float or generally | of straw, wood, | sink on solution, and may easily | paper, etc. | be seen. -------------------------------------------------------------------------

G.M. JONES, M.P.S.

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THE CATASTROPHE AT CHANCELADE.

The Chancelade quarries near Perigneux, which caved in Oct. 22, 1885, under circumstances that are still fresh in the minds of all, have gained a celebrity that renders it unnecessary for us to revert to the details of the catastrophe. It will suffice to recall the fact that after the accident a private committee was formed for the purpose of making an attempt to save the five victims who had been surprised in the drifts, and who happened to be in the bottom levels.

The Lippmann establishment at once offered to make a boring by means of which it would be possible to communicate with the galleries in which the men were imprisoned, but, despite the most active efforts, success was found impossible. In order to satisfy public opinion, the committee resolved to bore a well 12 inches in diameter to a depth of 23 feet, that should permit of reaching the gallery; but this did not render the latter accessible. How was it to be seen what had occurred, how was it to be made certain that the men were dead, and that all hope of rescue must be abandoned? To Mr. Langlois, a Parisian photographer, was confided an order to construct a special apparatus which might be let down to the bottom of the well by a cord, and which, being capable of operating from a distance, should furnish the required information through sensitized plates. As may be seen, this operation presented peculiar difficulties, although Mr. Langlois was enabled to overcome these with much skill.

The photographic apparatus that the ingenious operator constructed was contained in a metallic case that could be let down into the bore hole. The upper and lower parts of the contrivance were provided with incandescent lamps, that could be lighted or extinguished from a distance, by means of conductors. The photographic apparatus, properly so called, formed of an objective and camera with its sensitized plate, was inclosed in a cylinder 3½ inches in diameter. By means of a cord drawn at the mouth of the well, the apparatus could be made to issue from its vertical sheath, and to pivot around its axis so as take views in different directions (Fig. 1).

The entire affair was suspended by twelve-foot iron rods, connected with each other end for end.

In using the apparatus, the operating was done in a shanty, which served as a dark room. The device was let down into the bore well until it touched bottom. At this moment a cord was pulled so as to raise the camera, and then a few moments were allowed to elapse in order that the apparatus might become immovable. As the objective was all the time in the dark, it had neither cap nor shutter, but was unmasked from the beginning of the operation.

In order to form an impression on the plate, it was only necessary to give light; this being easily done by passing an electric current by means of a commutator, so as to light the incandescent lamps. At the end of the exposure, the lamps were extinguished and the entire apparatus was immersed in darkness. The mean time of exposure was from four to five minutes. The apparatus was then hauled up, and the negative developed.

The experiments could be renewed as often as necessary, and the apparatus be pointed in all directions by turning it a certain number of degrees by means of a lever attached to the upper rod. In this way were obtained various views of the inaccessible gallery in different planes.

We reproduce herewith two of Mr. Langlois' most interesting photographs. One of these shows the head of the corpse of a young miner whose face stands out in relief against the side of the gallery (Fig. 2) the other shows a wheel and a lot of debris heaped up pell-mell (Fig. 3).

The series of proofs obtained from small negatives, two inches square, gave the completest sort of information in regard to the aspect of the subterranean gallery.

The exact place where the boring had been done and the entire and broken pillars were recognized, as was also the presence of two corpses, thus showing that it was indeed here that it would have been necessary to act in order to render aid to the unfortunates.

In Fig. 4 is shown the appearance of the great fault that caused the accident at Chancelade. It seems to us that this method of photographing inaccessible subterranean galleries ought to receive numerous applications in the future.--_La Nature._

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SOMZEE'S NEW GAS-BURNERS.

With the object of effecting a very intimate mixture of gas and air, and of causing this mixture to reach the point of ignition at as high a temperature as possible, M. Leon Somzee, of Brussels, has designed several new forms of gas burner, which we now proceed to describe and illustrate, from particulars and by drawings kindly supplied by an esteemed Brussels correspondent.

The high-power burner shown in Fig. 1 effects perfect combustion of the heated mixture of air and gas, which is introduced by the draught determined by the arrangement. What chiefly distinguishes this burner from others of its class is the fact that it is perfectly suited to domestic lighting--that is to say, it may be arranged for a comparatively small consumption of gas, while giving an increase of 250 per cent. of light.

The burner proper is a cage or basket of specially prepared magnesia, which yields a warmer tone of light than any obtained hitherto, while not requiring so high a temperature before combustion. The cap, made of a fire-resisting substance, fits on to a tubular arrangement, R, fixed in the upper portion of the body of the burner. The latter is supplied by air entering at the cone, O, which terminates the inner chamber, K, of the heater, and also by that drawn in by the rising column of gas, passing before the orifices, D, which may be regulated at will. The small burner, I, which is kept constantly alight, heats the central compartment, K, the sides of which transmit heat to the gas circulating in the annular casing, L, of the compartment. The heated gas passes, by the passage, AA¹, into the space, C, where it becomes intimately mixed with the air entering at OP, and also with the outer air arriving by the lateral apertures, D.

The _vis viva_ of the jet is diffused through this mixture, which thus becomes very intimate, when it penetrates into the tubular arrangement, R; combustion now taking place at the top, while the refractory cap emits a bright orange light of great steadiness. As it is not the flow of gas which determines the entrance of the outer air, the former may be used at any pressure--an advantageous arrangement in all respects.

When the small burner, I, in the lower chamber is lighted, the products of combustion issue by the orifice, O, of the compartment, terminating in a needle like that of the steam injector; and the jet draws along the air entering the apertures, PP, above the cone. The gas from the pipe, arriving from the annular space, L, fills the two lateral pockets shown in dotted lines, and passes through the orifices, AA¹, which communicate with the upper chamber of the burner. The manner in which it is conveyed thence to the tubular arrangement has already been described.

Fig. 2 shows a more simple method of carrying out the same principle, and of effecting a considerable saving in gas for a given intensity of light. In this form, a wick, T, impregnated with an alkaline earthy solution, a few seconds after lighting, affords a focus of white light remarkable for its steadiness and brilliancy. A draught of air is created by a jet of gas issuing from the hollow needle, B, and passing through the vessel, D, which is provided with orifices, O, for the entrance of air. The air and gas pass from D into C, whence (after their intimate mixture is effected) they pass into the tubular arrangement, F, at the top of which combustion takes place.

To regulate the proportions in which the air and gas should mingle, in order that the combination should be as intimate as possible, the air inlet is made variable by a perforated collar, which permits of the orifices, O, being more or less covered. The other proportions of the burner--that is to say, the relative capacity of the two compartments and the length of the hollow needle--are determined by the sectional area of the supply-pipe for the gas, which is admitted under moderate pressure. Instead of a wire-gauze cap, impregnated with a solution of metals or of salts, two fine platinum wires may be used--one bent into the form of a semicircle of about an inch radius, and the other (of slightly larger diameter) rolled spirally round the former. When both ends of the two wires are connected with the upper portion of the tubular arrangement (which in this case is flattened), and the gas is ignited at the burner, the metallic arc becomes red hot, and then brightly incandescent, emitting a light, less brilliant indeed than with magnesia, but of remarkable steadiness.

In this case the production of light is chiefly due to the fact that calorific condensation, caused by the use of the helicoidal coil surrounding the curved wire, prevents loss of heat in this conductor. In these forms of high-power burner, in which the gas is used directly for the production of light, the difficulty generally encountered of heating the air (present in a larger volume than the gas) has been successfully overcome.

Fig. 3 shows the straight and outspread flame burner with a special heater. In this arrangement the gas and air are heated before combustion, in the compartment, G, directly exposed to the action of a small Bunsen burner, R, which is placed (in an opaque glass) in the middle of a lyre-shaped figure formed by the two gas-pipes, AA. The burner proper consists of two fine annular passages meeting above, and emitting a thin annular sheet of gas over the guide, T, made of a white refractory substance placed between the two annular jets. The object of this guide is to stretch the incandescent sheet of flame, composed of several jets, and interpose friction, so as to prevent a too rapid ascent of hot gases.

The luminous focus is placed within a glass globe, C, mounted on the bell, B, of the heater; and the external air enters this bell, mingling with the products of combustion of the heating burner, R. The portion, D, of the annular passage, B, being made of a highly conductive metal, the gas becomes heated in passing to the burner, so that both gas and air are raised to the same temperature by the time they reach the orifices of the burner. Instead of prolonging the gas-pipe to the point of bifurcation, a chamber may be arranged immediately below the guide, for the gas and air to become intimately mixed by passing through several perforations or wire gauze, receiving the excess of heat from the white porcelain guide. The admission of gas to both the main and heating burners is regulated by a double valve in the pipe; but this arrangement may be used without any previous heating of the gas and air.