There are also fatty bodies which, in an artificial way, form an emulsion even with water; for instance, almond, poppy and hemp, if they are ground to a pulp with a little water yield a milky mixture. All these emulsions artificial as well as natural, can be employed as expanding mediums and give better results for marbling than petroleum or naptha.
Substances Acting Similarly to Gall.
SUBSTANCES ACTING SIMILARLY TO
GALL.
There are rosins which are soluble in ammonia or borax. These solutions possess properties similar to gall and either can be used as an expanding medium or as an addition to colors. Different experiments with these solutions gave very good results.
To produce them pour a quart of water into a vessel, warm, add 2/5 of an ounce of shellac or rosin and a 1/100 part of a quart of ammonia or 2/5 of an ounce of borax so that the rosin becomes dissolved, and then bring the mixture to a boiling temperature.
Ammonia dissolves the rosins much more quickly and thoroughly than borax, but the solution in ammonia has the property of gelatinizing the colors after they have remained standing a short time. They therefore can only be used in a greatly diluted condition. The borax solution, on the other hand, has no such effect; not even the concentrated solution. I mention these two solutions especially, to instigate further investigations.