The legend continued that the Prince, though he kept the carriage and horses as a trophy, liberally paid for them. The author of the Tres Centuriæ, who does not record the secret of the little arrangement, declares that he does not know whether it was all done by a fraud or by magic. If it was the latter, I regret that the incantation by which broken crockery is mended is now lost. The most powerful spell known to me is Recipe Gummæ Mastichæ duæ unciæ cum Spirito Vini fiat mixtio—that is, mastic cement. It is generally combined with sturgeon’s bladder glue.
This cement answers very well for glass. One of the old recipes, which was very good indeed, is thus given by Johannes Wallburger (1760):—“Take finely cut and a little powdered sturgeon’s bladder” (still sold by all chemists), “soften it all night in spirits, add to this a little clean and powdered mastic, boil it a little in a brass pan. Should it become too thick, add a little spirits.” This may be also used for many other purposes.
A strong but coarser adhesive, especially for crockery and stone, can be made as follows:—Take old and hard goat’s milk cheese, and warm it in hot water till it forms, by pounding, a mass like turpentine. Add to this, while grinding, finely pulverised quicklime and the well-shaken white of eggs.
I do not hesitate to give a variety of such recipes, because in every one the artist will find valuable suggestions for other purposes than simply glueing broken articles together. This latter is a valuable “filler” for many purposes. Glue was formerly made into a strong cement by boiling it for a time in water, but before it had become incorporated with the water, the latter was poured off and strong spirits substituted and stirred well in.
A very popular old cement for crockery, of which there were several variations, was made by mixing glue, turpentine, ox-gall, the juice of garlic, and sturgeon-bladder, tragacanth, and mastic. All of this singularly smelling mixture was put into a pan and boiled in strong spirits, such as whisky, then kneaded on a board under a roller, again boiled with more spirits, yet again rolled, and this was repeated a third time, and then cooled till it could be cut into cakes. When these were to be used they were again steeped in spirits. But with this cement, glass or metal could be most firmly attached to wood. I confess that I have never tried it, but it was evidently a very strong cement.
Another of these somewhat complicated recipes for crockery, glass, and porcelain, which I find in the Tausandkünstler, 1782, is as follows:—Half an ounce of finely cut sturgeon’s bladder, two teaspoonfuls of alabaster powder or gypsum, quarter of an ounce of tragacanth, one teaspoonful of silberglatt, two of powdered mastic, two of frankincense, two of gum-arabic, one of Marienglas, one tablespoonful of spirits of wine, one of beer-vinegar. Boil it and stir, and apply. Any drops sticking to the mended article may be removed with vinegar. When it is to be used again revive it by heating, adding spirits of wine and beer-vinegar. The gum-frankincense is here worth noting.
A common cement for mending broken glass or china is prepared as follows:—To two parts of gum-shellac add one of turpentine; boil them over a slow fire, and form the mass into small cakes before it dries. To use it, warm with a lamp. To mend ivory or wood, take a cake and let it dissolve in spirits of wine.
A very strong cement is made as follows:—Take one ounce of finely powdered mastic dissolved in six of spirits of wine and two ounces of shredded sturgeon’s bladder dissolved in two ounces common spirits; add one half ounce of gum-ammoniac as it hardens; warm it when it is to be used. This is as strong a cement as can be made.
Defects, cracks, and repairs in porcelain, &c., may often be concealed as follows:—Paint the spot with silicate of soda, not too much thinned, and dust it over before it dries with bronze powder. This will set so hard that it may be polished with an agate burnisher.
It is also possible that many of my readers have heard of gesso painting, an art perfected by Mr. Walter Crane. This consists of painting with plaster of Paris in solution, with the point of a brush, depositing the soft paste in relief. The same principle is applicable to painting in silicate and whiting on glass surfaces. By means of it decoration can be given to any glass bottle or other object.