VARNISH. 
two ounces of alcohol by a gentle beat. 
Five ounces of shell-lac and one of turpen- 
tine, dissolved in thirty-two ounces of alco- 
hol by a very gentle heat, give a harder 
varnish, but of a rgddish cast. To lliese 
the solution of copal is undoubtedly prefer- 
able iu many respects. This is eft'ected by 
triturating an ounce of powder of gum co- 
pal, wdii'ch has been well dried by a gentle 
beat, with a drachm of camphor, and, while 
these are mixing together, adding by de- 
grees four ounces of the strongest alcohol, 
without any digestion. 
Between this and the gold varnish there 
is only this difference, that some substances 
that communicate a yellow tinge are to be 
added to the latter. The most ancient de- 
scription of two sorts of it, one of which 
was prepared with oil, and the other with 
alcohol, is to be found in “ Alexius Pedehion- 
tanus Dei Secret!, ” Lucca, of which the first 
edition was published in the year 15.‘ 7. But 
it is better prepared, and more durable, 
when made after the following prescrip- 
tion : Take two ounces of shell lac, of ar- 
natto and turmeric of each one ounce, and 
thirty grains of fine dragon’s blood, and 
make an extract with twenty ounces of al- 
cohol in a gentle heat. 
Oil varnishes are commonly mixed imme- 
diately with the colours, but lac or lacquer 
varnishes are laid on by themselves upon a 
burnished coloured ground : when tl^ey are 
intended to be laid upon naked wood, a 
ground should be first given them of strong 
size, either alone or with some earthy co- 
lour, mixed up with it by levigation. The 
gold lacquer is simply rubbed over brass, 
tin, or silver, to give them a gold colour. 
Pere d’lncarville has informed us, that 
the tree which affords the varnish of China 
is called tsi-chou by the Chinese. Tliis 
tree is propagated by offsets. AV’hen the 
cultivator is desirous of planting it, he 
takes a branch, w'hich he wraps up in a 
mass of earth, by means of flax. Care is 
taken to moisten this earth ; the branch 
pushes out roots, and is then pruned and 
transplanted. This tree grows to the size 
of a man’s leg. 
The varnish is drawn in spring. If it be 
a cultivated tree, it affords three gather- 
ings. It is extracted by incisions made in 
the spring ; and when the varnish, w’hich is 
received in shells, does not flow, several 
hog’s bristles, moistened with water or saliva, 
are introduced into the wound, and cause' 
it to run. When the tree is exhausted, the 
upper part of it i* wrapped in straw, which 
is set on fire, and causes the varnidi to pre- 
cipitate to the bottom of the tree, where 
it flows out of perforations made for that 
purpose. 
Those who collect the varnish set out be- 
fore day-break, and place tlieir shells be- 
neath the apertures. The shells are not left 
longer than three hours in their place, be- 
cause the heat of the sun w’ouhl evaporate 
the varnish. 
The varnish emits a smell, which the 
w'orkmen are very careful to avoid respir- 
ing. It produces an effect which they call 
the bud of the varnish. 
When the varnish issues from the tree it 
resembles pitph. By exposure to the air, 
it gradually becomes coloured, and is, at 
last, of a beautiful black. 
The juice which flows from incisions 
made in the trunk and branches of the 
rhus toxicodendron possesses the same pro- 
perties. It is a white milky fluid, which 
becomes black and thick by the contact of 
the air. 
To make the varnish bright, it is evapo- 
rated by the sun ; and a body is given to it 
with hog’s gall and sulphate of iron. 
The Chinese use the oil of tea, which 
they render drier by boiling it with orpi- 
raent, realgar, and arsenic. 
To varnish any substance, consists in ap- 
plying upon its surface a covering of such 
a nature, as shall defend it from the influ- 
ence of the air, and give it a shining ap- 
pearance. 
A coat of varnish ought, therefore, to 
possess the following properties : 1. It must 
exclude the action of the air ; because 
wood and metals are varnished to defend 
them from decay and rust. 2. It must re- 
sist water ; for otherwise the effect of the 
varnish could not be permanent. 3. It ought 
not to alter such colours as are intended to 
be'preserved by this means. 
It is necessary, therefore, that a varnish 
should be easily extended or spread over 
the surface, without leaving pores or cavi- 
ties ; that it should not crack nor scale ; and 
that it should resist water. Now resins are 
the only bodies that possess these proper- 
ties. 
Resins, consequently, must be used as the 
bases of varnish. The question which of 
course presents itself, must be then, how to 
dispose, them for this use ; and for this pur- 
pose they must be dissolved, as minutely 
divided as possible, and combined in such 
a manner, that the imperfections of those 
