252 A Treatise on 
being commonly done in the Dog-Days; though 
we are told that one Man, by following his Bulinefs 
clofely, may collect above three Pounds in a Day. 
However, it is very hard to come at any which is 
entirely pure ; for they who get it, being not con- 
tent with their Gains, to encreafe its Weight mix 
with it a Sort of black Sand, wherein is contained 
a certain Proportion of Iron. 
In a chymical Analyfis two Pounds of twilled La- 
danum yielded two Ounces, two Drachms, and 
forty eight Grains of reddifh Oil, of a pleafant 
Scent and acid Tafte ^ three Drachms and an half 
of brown Liquor which was alkaline, coagulating 
the Solution of corrofive Sublimate and fermenting 
with Acids ; four Drachms and twenty four Grains 
of reddifh, tranfparent, odorous Oil •, with one 
Ounce and three Drachms of brown Oil, fomewhat 
empyreumatick and thick. The black Subftance 
which was left behind weighed twenty fix Ounces 
and feven Drachms j and being calcined by a re- 
verberatory Fire in a Crucible for eight Hours ac- 
quired a brownilh yellow Colour, which afterwards 
became reddifh by continuing the Calcination for 
fix Hours longer. At the lalt it appeared to be 
nothing more than an infipid Sand, affording fcarce 
any fixt Salt at all. This Sand without doubt had 
been mixed with the Ladanum. 
Hence then it is evident that Ladanum confifls 
of a thin and thick Oil, combined with an effenti- 
al ammoniacal Salt •, and moreover that in two 
Pounds are contained about twenty four Ounces of 
Sand, fo that one Pound of common or twilled 
Ladanum produces hardly lour Ounces of the pure 
Refin. As the Sand has feme Particles of Iron in 
it, it is no wonder that it changes red in Calcina- 
tion like the Crocus Martis. 
■ Ladanum 
