The distemper itself is the simplest thing in the world. It is only a proportion of water and yolk of egg (he deprecates the use of vinegar), to which he adds a certain number of drops (I have not the recipe by me) of this gum. Of course it would be important not to use the wrong gum. Hence the trouble I am giving you.
January 27, 1890.
I have just received from Perugia the enclosed sample of Gum Dammar, which you were kind enough to say that you would report upon to me. A few drops of this (by-the-bye, I do not know how it is to be dissolved) and the yolk of an egg stirred in water, form the distemper used by my friend Mariani.
I don't know whether I told you that he is rather an interesting fellow. He is one of those extremely dexterous Italian workmen-artists who know and can work in every material, and whose forgeries of sixteenth century bric-à-brac, cassoni, reliefs in pastiglia, &c. &c., have, I am afraid, not infrequently been purchased as original by very crafty persons.
Several friends of mine who use distemper, and he amongst the number, tell me that by putting a preparatory coating of distemper over thoroughly dry oil, you can with perfect safety interpose a layer of painting in distemper between two paintings in oil—an extremely valuable thing for us for recovering quality.
January 31, 1890.
Many thanks for your valuable letter. I have had the information entered in a little book, where I keep the outpourings of your wisdom on matters chemical.
Thanks also for the card, in which you give me a somewhat long name for my Gomme Dammar. I suppose in an appeal to a chemist the first portion would suffice.