SILVER. 181 
silver. All these are performed by different chemical 
preparations of this metal. 
The article denominated, shell-silver, used by painters, 
is prepared, by carefully grinding silver-leaf, with a 
little honey or gum water upon a slab, or in a mortar, 
and separating the honey or gum by means of water. 
When this is washed away, the silver may be put on 
paper, or kept in shells, for use. When it is to be used, 
it must again be diluted with gum water. 
The application of silver-leaf for the silvering of paper 
or wood is similar to that of gold-leaf (227). 
Silver, dissolved in aqua fortis (nitric acid, 30), yields 
crystals, which, afterwards melted in crucibles, form 
that grey mass usually called lunar caustic, and by che- 
mists nitrat of silver. This preparation is of consider- 
able use in surgical cases, being employed to keep down 
fungous or proud flesh, in wounds and ulcers, and also 
for the consuming of warts, small wens, and other ex- 
crescences upon the skin. It is 'likewise, though a most 
violent medicine, sometimes" given internally, but in 
very small doses, to persons subject to epileptic fits. 
The liquid in which the silver is dissolved becomes ex- 
cessively caustic. It gives to the skin, the hair, and 
almost all animal substances, an indelible black colour. 
Hence it is often used as a specific for dyeing the hu- 
man hair. No person, however, would employ it for 
this purpose, who was acquainted with its injurious 
qualities, not only to the hair itself, but also to the skin, 
if permitted to come in contact with it. 
The article called indelible, or permanent marking ink T 
for marking linen, and other wearing apparel, is formed 
by dissolving, in a glass mortar, two drachms of nitrat 
of silver, in six drachms of pure water, and then adding 
to them, two drachms, by measure, of thick gum water. 
This is the ink for writing on the linen. In another 
vessel dissolve half an ounce of salt of tartar, or of the 
subcarbonat of soda, of commerce, in four ounces of 
water ; and add to the solution half an ounce, by mea- 
sure, of thick gum water. This forms the preparatory 
