Take common glue in very small or thin bits, and isinglass glue: infuse them in as much spirit of wine as will cover them, for at least twenty-four hours. Then melt the whole together, and, while they are over the fire, add as much powdered chalk as will render them an opaque white.
The infusion in the spirit of wine has been directed in the recipes given for glue; but the remark on the use of it in one of the preceding articles will hold good also in this, and the mixture may be made with water only.
TO MAKE COMPOUND GLUE.
Take very fine flour, mix it with white of eggs, isinglass, and a little yeast; mingle the materials; beat them well together; spread them, the batter being made thin with gum-water, on even tin plates, and dry them in a stove, then cut them out for use. To color them, tinge the paste with Brazil, or vermilion for red; indigo or verditer, &c., for blue; saffron, turmeric, or gamboge, &c., for yellow.
TO MAKE ISINGLASS GLUE.
This is made by dissolving beaten isinglass in water by boiling, and having strained it through a coarse linen cloth, evaporating it again to such a consistence, that, being cold, the glue will be perfectly hard and dry.
A great improvement is made in this glue by adding spirit of wine or brandy after it is strained, and then renewing the evaporation till it gains the due consistence.
TO MAKE ISINGLASS SIZE.
This may also be prepared in the manner above directed for the glue, by increasing the proportion of the water for dissolving it, and the same holds good of parchment size. A better sort of the common size may be likewise made by treating cuttings of glovers’ leather in the same manner.