SEPARATING GOLD FROM ALLOY.
Gold coins and gold jewelry always contain alloy. Gold being too soft a metal to use alone is mixed with some harder metal, so that the article will wear longer. Pure gold is 24 carats fine. Before the metric system was adopted, a mark—a gold coin—was used as the unit of standard weight, and a carat is 1/24 of the weight of a mark. A carat is used to express the proportion of gold in the alloy. If a coin is 22 carats fine, it means that it contains 22 parts of pure gold. An article that is 18 carats fine contains 18 parts of pure gold and 6 parts of alloy. Gold coins contain so little alloy that it is not necessary to separate the gold from the alloy; but if one is preparing chloride of gold from old jewelry, in which are found perhaps only nine parts of pure gold, it is best in using it for special work to separate the two metals. This can be done with very little trouble.
Dissolve the gold in "aqua-regia," according to the directions given in the last number of the Round Table. When it is dissolved and the acid evaporated, dilute the chloride with clear water, and add a small quantity of ferrous sulphate. This will cause the gold to be precipitated, and it will settle to the bottom of the vessel in the form of a brown powder, while the alloy will remain in solution. It will take some time for the gold to settle, and when it is all deposited or precipitated turn off the water carefully, wash the gold in distilled water, and then redissolve it in fresh aqua-regia, following the directions in our last paper on preparing chloride of gold. Ferrous sulphate, the substance which precipitates the gold, is also called sulphate of iron. It is a chemical compound, and the chemical formula is FeSO4+7H2O, meaning that one atom of iron, one of sulphur, and four of oxygen are added (+) to 7 molecules of water (7H2O).
In the directions for preparing printing-paper for violet prints the directions for the coloring-bath read as follows:
SEL D'OR (DOUBLE SALTS OF GOLD).
| Sel d'or | 7½ | grs. |
| Distilled water | 15 | oz. |
| Hydrochloric acid | 1 | drachm. |
A member of the Camera Club, wishing to try the formula, wrote to the editor that he went to a druggist for the "sel d'or," but was unable to obtain it, nor could the druggist tell him what it was. An explanation was sent by mail, but we repeat it for the benefit of the club. "Sel d'or" is a double salt of hyposulphite of soda and gold chloride. It is formed by adding chloride of gold to a hyposulphite solution, and mixing with alcohol. Take three parts of concentrated solution of chloride of gold and one part of concentrated solution of hyposulphite of soda. Mix thoroughly, and add alcohol till it is well covered. Shake well, and then set it aside. The alcohol will cause the chloride of gold and sodium sulphite to be precipitated in the form of delicate needlelike crystals, almost transparent, and readily dissolved in water.
If one cannot, obtain "sel d'or" ready prepared, it is not much work to prepare it. This double salts of gold is the form in which gold was used for toning daguerreotypes in the early days of photography. The silvered plate on which was the picture was coated with a solution of "sel d'or," and then heated. The gold was melted or decomposed by the heat and deposited on the picture, giving it not only a beautiful tone, but also preserving it. That this preparation made the picture durable is shown from the fine daguerreotypes which, though taken so many years ago, still retain almost their first freshness.
Sir Knight W. Baker asks if there is any difference between a sulphite and bisulphite. A sulphite is a salt formed by the union of sulphurous acid with a base. For instance, sulphite of soda is a salt formed by the union of sulphurous acid and sodium, the sodium being the base. A bisulphite is a sulphite in which the metal has replaced but half the hydrogen in the acid. "Bi," used chemically, means that the compound contains two equivalents of the substance named.
Sir Knight Lester R. Moss asks which camera to buy—a "B." daylight or a Kodak, both same price. Would advise a Kodak with glass plates for a beginner. A camera in which films are used is not so satisfactory as one for glass plates, and one can learn how to manage a camera much better if plates are used. Sir Knight Lester asks how he may become a member of the Round Table. Your name has been placed on the membership list. To become a member all that is required is that one should send name and address, and state that he wishes to become a member.
Sir Knight F. G. Clapp sends grateful acknowledgment for query answered in the Round Table for March 31.
Will Max Miner be kind enough to write to the editor and give the name of the camera which he used in making the picture, reproduced in the Round Table, called "Sweeping a Sliding-Place"? A member of the Camera Club is anxious to know. Will Sir Max also add the name of lens and plate used?
[THE PUDDING STICK.]
This Department is conducted in the interest of Girls and Young Women, and the Editor will be pleased to answer any question on the subject so far as possible. Correspondents should address Editor.
I am fond of perfumes myself, and so I know just what Elizabeth Rosa means when she sighs: "Oh, how I wish I could have all the violet extract I want! But I cannot afford to buy it, and nobody ever gives me any, except sometimes Aunt Susie at Christmas. There is Lettie, whose writing-paper always reminds you of flowers, a faint far-away sweetness, and Norah, who leaves a dream of roses in the room she has been sitting in, and Eleanor, whose gowns have a delicate fragrance; but there, it's of no use; I am poor, and I can't compete with those girls!"
Really, my dear, your style is poetical. A dream of roses is very impressive. Now let me give you one or two secrets of perfume.
To have your writing-paper, whether note or letter size, or a plain businesslike pad, carry with it a breath of dainty sweetness, you must keep it in tightly closed boxes in which are little packets of orris powder. Your bureau drawers will be perfumed, and the perfume will creep into your handkerchiefs and ribbons and your under-clothing if you will line the drawers with tissue-paper; sprinkle this with powdered orris, and lay a sheet of tissue-paper above it. A prettier way is to make a sachet the exact size of your drawer by quilting orris powder between folds of China silk. Little bags of silk filled with orris and kept in the pockets of your gowns will give them a very delicate fragrance.
A pronounced perfume is vulgar. You must have merely a suggestion of it—a whiff—gone in a breath, not a coarse heavy odor which makes your friends think of musk or patchouly. Perfume poured from a bottle is apt to scent a handkerchief too strongly to please a fastidious taste. You may use your cologne or your violet essence a few drops at a time in the water in which you bathe, or you may finish your toilet by wetting your hands with a tiny drop or two of your favorite perfume. Liquid perfumes must be used sparingly.
In toilet soaps for the face and hands select the nicest you can afford. Do not be afraid to use soap on your face. At least once a day wash it thoroughly with warm water and soap, as only thus can you get rid of the dust which clogs up the fine lace-like net-work of the skin. Make a lather and rub the face thoroughly. Then wash it off with clean water.
I may add that fresh rose leaves sprinkled plentifully in bureau drawers or in the linen closet give a very agreeable perfume to their contents. And we have all heard of the delicate sweetness of sheets and pillow-slips laid away in lavender.
Remember that the nicest people are fastidiously clean. The dainty girl uses a dash of ammonia in the bath, and keeps everything belonging to her spotlessly neat. Clothing should be frequently changed, and every detail of a girl's should be fresh and pure. One who is careful in this way needs no perfume in her toilet.
Margaret E. Sangster.
