On the Origin of Gum Sandarac, &c. 239 
Let the firft variety of filiceous ores be fuppofed to contain, 
filex 12, clay 8, lime 5 = 25. 
~ For an affay of 4 troy ozs. of ore = or 1920 grains, 
add 4 chalk — 1920 
3 bottle glafs — 1440 
o2 charcoal — 360 
“113. . 5640 
And, laftly, let the fecond variety of this genus of iron- 
fione be fuppofed to contain, filex 10, lime 7, clay 5 = 22. 
To 4 troy ouncesofthe ore - or 1920 grains, 
add 3: chalk — 1680 
3 —— bottle glafs — r440 
of charcoal — 360 
oy: ; 5400 
Clafs of equalifed mixtures, con:pofed of, clay 7, lime 7, 
fen. 7.2721. 
To aflay of thisore 4 troy ounces - or 1920 grains, 
add 35 bottle glafs — 1680 
ii chalk — 1200 
ot —— charcoal -— 240 
10! - 5040 
VI. On the real Origin of that Refin known under she; Name 
of Sandarac, and that of Gum Arabic. By M. Scuous- 
BOE rr ¥ 
Coun Sandarac is an article of trade brought from the 
fouthern provinces of the kingdom of Morocco. About fix 
_ ar feven hundred quintals of it are exported every year from 
Santa Cruz, Mogador, and Saffy. In the language of the 
country it is called El graffa. The tree which produces it 
is a Thuia, found alfo by M. Vahl in the kingdom of 
* From a Danifh Journal, entitled, The Phyfical, Medical, and Econo- 
pical Library, Part 1II. 1759. 
Tunis, 
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