Royal Societv.' j3j 
yields a grols black liquor, and what remains will be a little black 
Caput Mortutm^ like a fhining colophony, but deftitute either 
of oil or ialt^ out of a pound and a half of white amber, there 
was left an ounce of this Caput Mortuum-^ the volatile fait that 
afcends to the top of the veflel, or flicks to its fides is to be 
wafhed off with warm water, and in order to feparate it from the 
oily particles mixed therewith, flrain the Iblution thro' a wet 
paper, and the fait pafTes thro' whilil the oil remains behind, 
then evaporate the fuperfluous moifture from this filtred folution| 
until there remains about the third part, which being expofed to 
the cold air, it fhoots into cryflals of fait, in the form of millct- 
ieeds. 
There is another method of depurating the fait, which is by 
putting the lees into a long necked glafs, laid in a heat of afhes 
or land, the white flakes, or little fhoots, fly to the top, whilft 
the grofTer part remains at bottom 5 but this operation is attended 
with the lols both of the glafs and lalt together 5 fome endeavour 
to feparate the phlegm 5 but it is better put into the water that 
imbibes the volatile fait, that it may likewife be divcfled of its 
fait 5 nor does repeated diflillation give it any virtue, unlels it 
receives it from the volatile lalt - nor is the fmell of the phlegm fb 
agreeable as to preferve it. M. Hartman extracted from a pound 
and a half, an ounce and a half of white phlegm, of the tafle of 
fait of amber, but upon repeated diflillations it favoured only of 
Imoke, and was befides of a difagreeable tafte 5 there is Ibme fait 
in the colophony, if it is not quite burnt, which you may extract 
by macerating it with warm water for fome time 5 fome reckon 
this a fixed fait of amber 5 but what fort foever of fait this is, it 
adds to the virtue of the colophony 5 there is no occafion to de- 
purate the oil by another operation, for providing the recipient is 
changed in due time, and the diftillation properly fet about, you 
have the pureft directly; the qualities of the oil of amber are to 
be derived from bitumen, or the oil of the earth, wherein 
M. Hartman agrees with 'Borrichius^ but differs with him in that 
he would have all the virtues of the oil of amber to be common to 
Petroleum ; there is no amber of whatever colour, without its 
volatile fait, from which ariles irs peculiar fr«igrancy, and the 
more lalt it abounds in, the more fragrant you find it upon rub- 
bing; tho' ^V Hartman maintains, that the fair of amber is 
moftly compounded of vitriol of iron, which is plainly perceived 
both by the fmell and tafle in the white Ibrt that abounds very 
much in volatile fait, yet he does not alcribe lalt of amber to 
common vitriol. 
That 
