3 o 6 MATERIA MEDICA, 
for there is no great art in it. Thofe who work 
at it are miferable wretches ; as indeed are ail the 
common people in Egypt. The foot, and every 
thing elfe requifite for making the fait, is weighed 
to them, and they are obliged to deliver fait in 
proportion, by which they cannot wrong their 
mailers of an ounce. I lhall now defcribe the 
method of making it, which, though it is very 
fimple, has puzzled many chemilts. I doubt not 
butchemifts may invent fome better method, for 
this is very fimple. They build an oblong oven, 
about as long again as broad, of brick and moift 
dung ; of fuch a fize, that the outfide, or flat part 
of the top of the arch, may hold fifty glafs veflels, 
ten in length and five in breadth, each veflel having 
a cavity left for it in the brick work of the arch. 
Thefe glafs veflels are globular, with a neck an 
inch long, and two inches wide. They are of 
various fizes, in different fait works, containing 
from a gallon to two gallons •, but in general, are 
but eighteen inches diameter. They coat each 
veflel over with a fine clay, (which they find iO 
the Nile) and afterwards with ftraw ; they then 
fill them two-thirds full of foot, and put them into 
their holes on the top of the oven. 
They make the fire gentle at firft, ufing the 
above-mentioned dried dung for the fuel ; the/ 
increafe the heat gradually, till they bring it 
the higheft degree, which the workmen call hell' 
fire, and continue it fo for three days and thr ee 
nights together. When the heat is come to k s 
due degree, the fmoke fhews itfelf, with a fourilh 
fmell, that is not unpleafant ; and in a little time, 
the fait flicks to the glaffes, and covers the whol e 
aperture. The fait continues fubliming till the 
above time is expired j then they break the glaff e ®’ 
