- vapo

USEFUL PROJECTS.

amber in a crucible till it becomes
black, and then diflolving this
black fubltance, firfi reduced to a
powder, in linfeed-oil, orin a mix-
ture oflinfced oil and oil ofturpen-
tine-By melting the amber in
this prccefs, it fuffers a decom-
pofition, its nature is changed, and
part of its oily and faline matter is
expelled. The fame changes oc-
cur in the common dillillation of
this fubjeét: and when the dillil-
lation is not pufhed too far, the
ihining black mafs which remains
after the thinner oil and greater
part of the falt have arifen, is in
fuch a proportion folnble in oils,
as to (apply the common demand
of the varnifh-makers-This de-
cotnpolition, however, is not necef-
fary, as has generally been fuppofed,
in order to the folution : from the
curious experiments of Holiman,
Stockar, Zeigler, and others, it ap-
pears, that amber may be perfectly
diflblved, in expreffed oils, in tur-
pentine, and in balfam of copaiba,
ifit be expofed to the action of
thefe menftrua in clofe fiopt velTels,
and afiified by a due degree ofheat.
—-The folution may-be more expe-
ditioully made, if the fire be f0
firong as to convert part of the oil
‘into elaftic vapours; care mnPt be
taken to give fuch a vent to thofe
urs, as not to endanger the
burfiing of the velfel.

“ The folution,” fays Dr. Lewis,
“ in rapefeed-oil, and in oil of al-
monds, was of a fine yellowilh co-
lour; in linfeed-oil, gold-colour-
ed; in oil of poppy-feeds, yellow-

157

ilh red; in oil-olive, of a beau-
tiful red; in oil of nuts, deeper-
coloured; and in oil of bays, of a
purple red. It is obfervable, that
this lalt oil, which of itfelf, in
the greatelt common heat of the at-
mofphere, proves of a thick bu-
tyraceous confidence, continued
fluid when the amber was dilTolved
in it. The folutions made with
turpentine, and with balfam ofco-
paiba, were of a deep red colour,
and on cooling hardened into a
brittle mafs of the fame colour. All
the folutions mingled perfeftly
with fpirit of turpentine. Thole
made with the oils of linfeed, bays,
poppy-{eedg-and with nuts, and
with balfam of copaiba and tur-
pentine, being diluted with four
times their quantity of fpirit of
turpentine, formed hard, tenacious
gloliy varniihes, which dried fut"-
ficiently quick, and appeared great-
ly preferable to thofe made in the
common manner, from melted
amber.”

Of/Palizzg-euax.

LACK feeling-wax is com-
pofed of gum-lac *, melted
with one half or one third ofits
weight ofivory-black in fine pow-
der. The inferior fort of lac, called
{hell lac, anfsvers as well for this
ufe as the fineft. l: is cufiomary to
mix with it, for the tirdinary kinds
of fealing-tvax’, a contidcrable pro-
p0rtion,as two-thirds its weight, of
the cheaper relinous bodies, particu-
larly Venice turpentine, by which

' More properly called Stick Ia:.---Lac is a concrete brittle fubllanre, fail
to be collected from certain trees by a winged red meet, and depolizetl either an
the branches of the trees or on {ticks fixed in the earth for that purpvft . \Vnen

freed from thetinging matter it receives from the young izziluts, it 1S rt‘  Enter-

mediate nature between wax and relins.

the