the vessel is charged anew with bisul- | phide, and the pumping and charging repeated, until the liquid runs off quite colorless, and leaves no grease stain upon printing paper after evaporation. Four ounces of seed will usually require about 16 ounces of bisulphide of carbon. To separate the bisulphide of carbon from the oil, the still is filled three quarters full with water, heated by a lamp placed under it, and the fluid to be evaporated poured into the saucer. When the bisulphide of carbon has been evaporated, the still is removed, the saucer placed over the lamp, and removed the moment the oil commences to boil. It is then allowed to cool off, and the oil contained in the saucer is weighed. By this process it was found that Saffron. Concentrated sulphuric acid is the surest means of testing saffron. The stigmas of the genuine article will immediately assume an indigo color, which changes quickly into dark red and brown, while the leaves of crocus vernus, the most common adulteration of saffron, are colored dark green. Asphaltum. To detect adulterations, dissolve a sample in bisulphide of carbon, filter, evaporate to dryness, and heat until it can be rubbed to a fine powder in a mortar. One part by weight of this is gently digested with 50 parts of sulphuric acid for twentyfour hours, and then gradually with 100 parts of water, and allowed to cool thoroughly. This mixture is filtered and diluted with 1,000 parts of water. The unadulterated asphaltum gives a colorless or pale-yellow fluid, while, if pitch, coal-tar, etc., are pres yielded 40 to 50 per cent. of oil. ent, it is dark brown or black. 66 66 66 66 Rape seed 34 White poppy seed : Vinegar may be adulterated: a. With Sulphuric Acid. To detect this adulteration mix a small sample with some powdered starch, boil it for half an hour, then allow it to become entirely cold (this is absolutely necessary); and add a few drops of iodine solution. The vinegar, in case it is adulterated, will be colored blue. b. With Nitric Acid. Mix a sample with solution of sulphate of indigo. The fluid becomes discolored, or assumes a yellowish color, if adulterated. c. Tartaric Acid. A specimen of the vinegar to be tested is evaporated nearly to dryness. The residue is extracted with alcohol, filtered and treated with a solution of potassium chloride. A white precipitate indicates adulteration. d. Lead is present when a sample of vinegar is evaporated to one quarter of its volume, and this, being treated with sulphuric acid, yields a white precipitate. Simple Process of Distinguishing Genuine Gilding and Silvering from Imitations. a. Gilding. Diluted solution of chloride of copper produces a black discoloration on imitation gilding, but has no effect whatever upon the genuine. b. Silvering. A mixture of equal parts of bi-chromate of potassium and nitric acid produces a red coloration on genuine silvering, while it has no effect upon the imitation. Milk. Besides the common method of diluting milk with water, another species of adulteration has recently been detected. It is now frequently sophisticated This with dextrine. fraud can easily be detected by means of a solution of iodine; if the specimen contains the smallest quantity of dextrine, it will acquire a red color. Wax floats in alcohol of 29°. By obAdulteration of Wax with Tallow. which the sample floats, the percentage serving the strength of the alcohol in of wax may be deduced as follows: ALLOYS. Alloys for Tea Pots. 88.55 parts of tin, 9.53 of antimony, 9.94 of zinc, 0.88 of copper. To Test Dyes for Adulteration. Red | 150.8 F., then adds 30 minims of phedyes must neither color soap solution nole, shakes the mixture and heats it nor limewater, nor must they them- in a water bath until the fluid becomes selves become yellow or brown after transparent. The test-glass is then alboiling. This test shows the presence lowed to stand quietly for some time. or absence of Brazil-wood, archil, saf- Genuine butter will give a clear soluflower, sanders-wood or the aniline tion, but suet, tallow or lard forms two colors. Yellow dyes must stand being separate layers of fluid, the upper of boiled with alcohol, water and lime which becomes turbid on cooling. water. The most stable yellow is madder yellow; the least stable are anotto and turmeric, while fustic is rather better. Blue dyes must not color alcohol red, nor must they decompose on boiling with hydrochloric acid. The best purple colors are composed of indigo and cochineal or purpurin. The test for blue applies also to them. Orange dyes must not color water, boiling water, alcohol, nor hy-tin and 0.24 of iron. drochloric acid green. Brown dyes must not lose their color on standing with alcohol, or on boiling with water. If black colors have a basis of indigo, they turn green or blue on boiling with sodium carbonate; if the dye be pure gallnuts, it turns brown. If the material changes to red, on boiling with hydrochloric acid, the coloring substance is logwood without a basis of indigo, and is not durable. If it changes to blue, indigo is present. To Detect Alum in Red Wine. Boil a sample of the wine for a few minutes. Pure wine remains unchanged, while the adulterated article becomes turbid. Simple Method for Distinguishing Genuine Butter from Artificial. Heat the suspected butter in a crucible or test-tube, to about 300° to 320° F. At this temperature artificial butter froths but little, and the mass exhibits irregular movements resembling those of boiling, accompanied by sudden, forcible shocks which frequently throw a part of the fat from the crucible. Casein at the same time is separated and forms on the edge of the crucible in small balls, which assume a brown tint, while the fat retains its original color. Genuine butter, under these circumstances, foams copiously, the agitation occasioned by boiling is not nearly so forcible, and the entire mass assumes a uniform brown color. W. G. Crock melts and filters the suspected butter. He then takes 10 grains of this, heats it in a test-glass, Oroide. This alloy, resembling gold (specific gravity 8.79), consists of 68.21 parts of copper, 13.52 of zinc, 0.48 of Britannia Metal. Köller prepares this as follows: 85.72 parts of tin, 10.34 of antimony, 2.91 of zinc, 0.78 of copper. Alloys for Taking Impressions of Coins, Medals, Wood Cuts, etc. Melt at as moderate a heat as possible, 4 parts of bismuth, 2 of lead, 2 of tin and 1 of worn-out metal types. Chrysorine. This alloy, in color, closely resembles 18 to 20 carat gold. It has a beautiful lustre and does not tarnish when exposed to the air. It consists of 100 parts of copper and 50 of zinc. It is used, like Prince's metal, for watch cases and parts of the works. Prince's metal consists of 6 parts of copper and 1 of tin, and resembles gold in color. Pinchbeck. This alloy, resembling gold in color, derives its name from the English town Pinchbeck, where it was first manufactured, and consists of 90 parts of copper and 30 of zinc. Robertson's Alloy for Filling Teeth. 1 part of gold, 3 of silver and 2 of tin. First melt the gold and silver in a crucible, and at the moment of fusion add the tin. The alloy, when cold, may be finely pulverized. Equal quantities of the powder and mercury are kneaded together in the palm of the hand to form a paste for filling teeth. Aluminium Alloys. Aluminium forms alloys with many metals. Those with copper, silver and tin are to some extent employed for technical purposes, the most important being those with copper, with which aluminium can easily be alloyed. Lange & Sons have obtained a patent in the United States for an alloy consisting of 95 parts of aluminium and 5 of copper, which is malleable, and used for clock springs. Ten parts of aluminium and 90 of copper give a hard alloy, but nevertheless ductile. It takes a high polish, resembles gold and is but little attacked by ammonium hydrosulphide. Aluminium Bronzes contain from 6 to 10 per cent. of aluminium. They are prepared by fusing chemically pure copper with aluminium. Aluminium bronze, consisting of 90 parts of copper and 10 of aluminium, is used more than any other composition. It gives sharp castings, is more easily worked than steel, may be engraved, rolled in sheets, and when exposed to the air suffers less change than brass, silver, castiron or steel. It is serviceable for ornamental articles, household utensils, parts of geodetical and astronomical instruments, pivots, gun and cannon barrels. Aluminium bronze can only be soldered with an aluminium alloy. Aluminium Alloy for Soldering Aluminium. I. Melt 20 parts of aluminium in a crucible. Then add gradually 80 part of zinc, and when this is melted some fat. Stir the mass with an iron rod and pour into moulds. II. Take 15 parts of aluminium and 85 of zinc. III. Or, 12 parts of aluminium and 88 of zinc. IV. Or, of aluminium can be worked like pure aluminium. It is harder than the latter, and takes a very high polish. An alloy with one-tenth per cent. of gold is as ductile as pure aluminium, but harder, although not as hard as that with 5 parts of silver. An alloy of 95 per cent. of aluminium and 5 of silver is white, elastic and hard. It is used for blades of dessert and fruit knives. Gold and Aluminium. 99 parts of gold and 1 of aluminium give a very hard but not ductile alloy, possessing the color of green gold. An alloy of 90 parts of gold and 10 of aluminium is white, crystalline and brittle. Ninety-five parts of gold and 5 of aluminium give an alloy as brittle as glass. An alloy, the color of which resembles gold so closely as to defy detection, is obtained by fusing together 90 to 100 parts of copper, 5 to 7 of aluminium, and 2 of gold. The resulting alloy is used for jewelry as a substitute for gold. Zinc and Aluminium. These alloys are very hard and take a beautiful polish. 3 parts of zinc and 97 of aluminium give an alloy as white as the pure metal, very ductile and harder than aluminium. It is the best of all alloys of zinc with aluminium. An alloy of 30 parts of aluminium and 70 of zinc is white, very brittle and crystalline. parts of aluminium and Tin and aluminium give brittle al92 of zinc. All these alloys are pre-loys when they contain little tin and pared as indicated above. The flux consists of a mixture of 3 parts of copaiba balsam, 1 of Venetian turpentine and a few drops of lemon juice. The soldering iron is dipped into this mixture. Silver and Aluminium are very easily alloyed. The alloys are harder than aluminium, but more easily worked. An alloy of 3 parts of silver and 97 of aluminium has a beautiful color, and is not affected by ammonium hydrosulphide. much aluminium, but those with a small quantity of the latter are very ductile, and may be used as substitutes for tin. They are harder and more elastic. An alloy of 3 parts of aluminium and 100 of tin is hard, and but little affected by acids. Five parts of aluminium and 95 to 100 of tin give a useful alloy. With bismuth and platinum aluminium gives very brittle alloys. Lead and aluminium do not alloy. With iron aluminium alloys so easily Equal parts by weight of silver and that the iron rods used in preparing aluminium give an alloy as hard as aluminium become coated with a lusbronze. trous covering, giving them the apAn alloy of 5 parts of silver and 100pearance of being tinned. According to Tissier, a slight percentage of iron exerts an injurious influence upon aluminium. He claims that 5 per cent. makes the aluminium hard and brittle, and so refractory that the pure metal can be fused upon the alloy. Debray, on the other hand, asserts that 7 to 9 per cent. of iron produces no perceptible change in the properties of aluminium. Iron can be easily separated from aluminium by fusing the alloy with saltpetre, which oxidizes the iron. Roger claims that the presence of aluminium in steel makes it very hard, and gives to it the properties of "wootz," or Indian steel. When steel contains but 0.008 per cent. of aluminium, the articles manufactured from it, when etched with sulphuric acid, will show wavy lines like Damascus steel. American Sleigh Bells. These bells, excelling in beauty, fine tone and small specific weight, are manufactured by fusing together 10 parts of nickel and 60 parts of copper. When this alloy has become cold, add 10 parts of zinc and two-fifths parts of aluminium, fuse the mass and allow it to cool; then remelt it with the addition of twofifths parts of mercury and 60 parts of melted copper. Platinum Bronze. By alloying nickel with a small quantity of platinum, it loses its slight tendency to oxidation, and is not affected by acetic acid. To prepare the alloy, the nickel is fused with the platinum and definite quantities of tin, without the aid of a fluxing agent. The following alloys may be used: Alloys Resembling Silver. I. 25 per cent. of manganese, 55 of copper, and 20 of zinc. II. 5 per cent. of manganese, 10 of nickel, 45 of copper, and 40 of zinc. III. 5 per cent. of iron, 20 of manganese, 6.5 of nickel, and 57 of copper. New Nickel Alloy. Fuse together in a reverberatory furnace 20 cwt. of finely powdered nickel sesquioxide and 1 to 2 cwt. of copper with 2 cwt. of fluorspar, or 1 cwt. of cryolite and 2 cwt. of anthracite coal. Purify the resulting alloy in any known manner. A nickel alloy in great demand for technical purposes has been prepared by Christofle and Bouilhet. It consists of 50 per cent. of nickel and 50 of copper, can be easily remelted, and is especially adapted for the manufacture of argetan (German silver). An alloy with 15 per cent. of nickel is remarkable for its ductility, homogeneity and white color. It can be rolled out into sheets about one-twentieth millimetre (0.019 inch) thick, and drawn out into wire of any desired diameter. It is used for ornaments of every kind. Lutecine, or Paris Metal. Eight hundred parts of copper, 160 of nickel, 20 of tin, 10 of cobalt, 5 of iron, and 5 of zinc. A new and very Fusible Alloy. Fuse a mixture of 79 per cent. of cast-iron, 19.50 of tin, and 1.50 of lead. This alloy has a beautiful appearance, fills the mould completely, and is therefore well adapted for casting small articles. It is malleable to a certain extent. Wood's metal, fusing below 158° F., consists of: Alloy for Music-Printing Plates, etc. Ten parts of tin, 12 of zinc, 3 of antimony regulus, 1 of copper, and 74 of lead. Jean, who introduced this compound, calls it "heterogeneous alloy." com This new Spence's Metal. pound, discovered by Spence, and used in England for manifold purposes, is obtained by melting the three sulphides of iron, zinc and lead with sulphur. The product is a dark gray mass of great tenacity, small power of conducting heat, a specific gravity of 3.4, and melting point at about 320° F. In congealing it expands like bismuth and type metal, and resists in a remark. able degree the action of atmospheric influences, alkalies and acids, even of aqua regia; its surface being scarcely affected after having been exposed to the action of the latter for four weeks. Its property of expanding in congeal |