REEF A CIS. 
lation of their essential oils;* all intended as 
* Oils of plants are obtained either by expression, where the oil is 
very copious, as in rape, linseed, See. or by infusion,—and the oil ex¬ 
tracted by distillation, or insblation; by w hich latter methods the 
fine essential qualities of the plant are preserved, and are hence called 
essential oils (see note to dyctamnus); which may be divided into two 
classes according to their specific gravities; some floating upon 
water, as lavender, mbit, marjoram, citron-peel, roses, &c.; others 
sinking to the bottom, as cloves, cinnamon, sassafras, &c.—Dr, Mon¬ 
ro, in his Treatise on Chymistry, v. ii. p. £11, hath given the method 
of preparing the essential oil of roses, as it is done in the East Indies, 
called the ottar of roses. —Take a very large earthen or stone jar, or 
a large clean wooden vessel; fill it with the leaves of the flowers of 
roses, very well picked, and freed from all seeds and stalks; pour on 
them as much pure spring water as will cover them, and set the vessel 
in the sun in the morning at sun rise, and let it stand till the evening, 
then take it into the house for the night; expose it in this manner 
for six or. seven successive days, and at the end of the third or fourth 
day, a number of particles of a fine yellow oily matter will float on 
the surface, which in two or three days more will gather into a scum, 
which is the ottar of roses : this is taken up by some cotton, tied to 
the end of a piece of stick, and squeezed with the finger and thumb 
into a small phial, which is immediately well stopped ; and this is 
repealed for some successive evenings, or while any of this fine essen¬ 
tial oil rises to the surface of the water. 
This oil is said to be sold at a guinea a drop in the East Indies, 
Trans, of the R. S. Edinb. vol. 2. 
The monks of St. Mark's Convent at Florence, are said to make 
very good ottar of roses for about eight pounds sterling an ounce. 
Smith's Tour on the Continent, printed 1793. 
The word ottar , used by the Asiatics to expiess the essence of roses , 
is originally Arabic ; and signifies an aromatic odour or perfume in 
general. 
