This must be freely used to make the cover adhere. When in time it shall become brittle, coat it over with a thick solution of asphaltum in turpentine or petroleum.
To seal bottles very securely, roughen the opening or mouth with a file or glass-paper, drive in a hard cork till half-an-inch below the top, and then seal it with silicate of soda mixed with marble-dust.
Chloride of zinc added to silicate of soda and oxide of zinc forms a very good cement, which will resist most influences.
Bread macerated with glue or gelatine, with a little glycerine, makes an admirable substance for artificial flowers, casts, medallions, &c. If worked with gum-arabic and a little alum, or dextrine, or common mucilage, we shall have the same result. It can also be worked with thin varnish or gutta-percha cement; also with diluted sulphuric or nitric acids to produce a hard substance. It may here be observed that bread is for certain work far superior to flour or starch paste, since the combination with yeast causes a development of cellular tissue, the result of which is a firmer and more wax-like substance. I was led to observe this at first, not from what I read of the action of acids on bread, but from observing the bread-flowers made by the Italian peasantry to adorn images of saints. I believe that in these there is a little vinegar mixed. They are quite wax-like. The bread used should be soft household bread, of course well kneaded with the acid and colours. Bread-paste would probably combine well with indiarubber in solution.
Of late, German illustrated newspapers have published patterns of small ornamental dishes made of dough or bread, intended to receive conserves of fruit and other edibles—the dishes themselves not being intended to be eaten.
Soft bread with a little varnish or any ordinary gum and a little glycerine, well worked, makes an admirable filler for cracks in wood. Combined with any gum, or even with tragacanth or peach or cherry gum, and lamp-black (or liquid Indian ink), it forms a cement which resembles ebony. The more thoroughly it is macerated the harder it will be. Casts of panels, &c., made with this are really beautiful. Rub with oil and the hand after it is quite dry. Add a few drops of glycerine and alum in solution to prevent cracking, or, better, a little indiarubber. Soft rye bread hardens to a rather tougher cement than wheat. Bread cement makes an admirable ground for gilding or painting. Bread macerated with lime and white of egg forms a very hard composition like ivory. Bread, glue, and glycerine, ditto.
Horse-Chestnut Paste.—This is called a cement, but it is properly a paste like that of flour. Horse-chestnuts are generally neglected, but they can be profitably utilised for paste, which admits of the same combinations as flour.
Waste tea-leaves from which the tea has been extracted can be macerated with gum and treated as rose-leaves to form artificial ebony. Carefully separate all the hard portions.
Gum for general use, like gum-arabic:—
| Common sugar, by weight | 12 |
| Water | 36 |
| Slacked lime | 3 |