At a recent meeting of the Physical Society, Berlin, Prof. Christiani exhibited as samples of a new method of preservation a series of organic bodies coated galvanoplas-tically. A mulberry leaf, a crab, a butterfly, a beetle, the brain of a rabbit, a rose-bud, and other objects, were plated with silver, gold, or copper, and showed all details of their outer form, down to the finest shadings. As to the process, it was stated that the objects to be preserved, being put into a solution of silver nitrate in alcohol, then dried and treated with sulphuretted and phosphuretted hydrogen, form good conductors, which, brought in the usual way into the galvanoplastic bath, can be coated with any desired thickness of a metallic deposit.
(or) Sulphur is dissolved in oil of spike lavender until it has a semi-liquid consistence; this is mixed with an etherial solution of gold chloride, and the mixture is evaporated to the consistence of paint. The surface to be gilt is then covered with the mixture and the object is carefully heated in a muffle, whereby the volatile substances are expelled, and the metallic gold is fastened upon the glass or porcelain.: The surface, thus metallised, is afterwards plated in the usual manner with solution of gold, and with the aid of a galvanic battery.
(6) Mix first in a crystal mortar, and then between a muller and a ground-plate glass, neutral platinum chloride with rectified essence of lavender, so as to form a thin syrup, which is applied with a brush in very thin layers upon the. object. After drying, heat in a muffle up to a dark red; this temperature reduces the platinum to the metallic state; it then appears with a perfect polish. After cooling, pass the whole object through aquafortis, which is without action upon the platinum, but destroys the impurities which may tarnish its surface. Rinse in plenty of water, wrap the object with a few turns of fine brass wire, having numerous points of contact with the platinised places, and dip into the gold bath. After a few minutes, the platinum is covered with gold which has the same adherence and polish. Rob the gold with chamois leather; this method dispenses with burnishing, which is costly, and often impracticable in the deeply indented parts. If the gilding is too red, add to the bath a few drops of a solution of doable cyanide of potassium and silver (liquor for silver electroplating). This method is preferable to that of baths with separate battery; the gilding has a bright instead of a dead lustre, and its adherence is greater.