Magilp is a gelatinous compound produced by mixing linseed-oil and mastic varnish together, used by artists as a vehicle in oil-painting. The proportions vary according to the work. It is thinned with turpentine. Found on http://www.probertencyclopaedia.com/browse/AM.HTM
1) Resin 
• (n.) Alt. of Magilph
Magilp is a gelatinous compound produced by mixing linseed-oil and mastic varnish together, used by artists as a vehicle in oil-painting. The proportions vary according to the work. It is thinned with turpentine.