Though, as we have already said, silver has no patina properly so-called, there is the tone and colour which has to be imitated. To dull silver--to give it, we mean, the leaden-brownish colour acquired by age--a mixture with sulphur or chlorine is used. A solution of pentasulphide of potassium--the liver of sulphur of the shops--is generally used. Liver of sulphur is prepared by thoroughly mixing and heating together two parts of well-dried potash and one of sulphur powder. This mixture also takes effect on cupriferous silver, but the result is not so fine. A velvety black is obtained by dipping the article into a solution of mercurous nitrate previous to oxidization. This method is used when a half polish is to be given to the silver, leaving the dark tones in the grooves. Another method consists of dipping the article into chlorine water, a solution of chloride of lime, or into _eau de Javelle_. Special works on metals also give many other methods and it is for the imitator to chose the best adapted for the particular case and to use his artistic criterion to obtain a convincing effect. Passing on to gold, more especially in jewellery, we may say that imitators and fakers have wrought havoc by filling the market with spurious products. Imitation in this branch ranges from copying the old art of working gold, of which the famous tiara of Saitaphernes, bought by the Louvre, is one of the most striking examples, to the small piece of jewellery with imitated enamels or more or less genuine stones. In this line there is something to suit all tastes, from the eager connoisseur, difficult to please, still on the look out for the marvellous jewellery of the Rennaissance and early sixteenth century, to the less exclusive, satisfied with later epochs down to the eighteenth century. There is no way of helping the neophyte to collect jewellery, not only because fine old pieces are extremely rare, but because no advice or theoretical hints can help the discernment of the genuine article, only sound and well-tested experience, gained often at great cost, is of any real avail. In this branch also there are imitations that are entirely new and others, like the above-said tiara, that have become such by the preponderance of restored parts, or because the latter are the most important artistically speaking. In the tiara of Saitaphernes the genuine part, if genuine, is the upper portion of the domed tiara, which is said to have been an ancient drinking cup reversed and placed at the top of the tiara. Many well-imitated rings are really old worn-out rings used for the circle, to show that they have been used, on which the artistic setting of the jewel or other ornamental part has been soldered.