408 On the Preparation of Amber Varnish , 
©cL break it into pieces ; and if it has a bright blackish- 
brown appearance on the fracture, and weighs about one- 
half of what it did before being melted, you may be cer- 
tain that it is proper for the intended purpose. Parties 
lar attention must be paid to this circumstance ; for, if the 
amber is fused too little, so that part of it remains unmelt 
ed, it will not be dissolved by the varnish ; and if the 
operation be performed with a continued and strong heat, 
it will be burnt and unfit for use. 
When the amber is kept over a weak fire it will not 
melt, but becomes a sort of blackish brown incrustation, 
which also may be employed for varnish provided it has 
not been too much or too little evaporated : it will be in 
the best condition when you obtain half a pound from a 
pound. If the amber is too little evaporated, it must 
be again put into the pan till it be reduced to the proper 
weight. The same thing is to be observed when you 
melt it; but the parts which are not fused must be picked 
out, in order to be afterwards also melted. 
I have found that a pan with a flat bottom is better than 
one with a round bottom, because the melting or evapo- 
ration is effected sooner in the former than in the latter; 
for in the latter the amber lies thick in the middle, and is 
burnt at the bottom and sides before it can be brought to 
melt or evaporate. 
It is not necessary, for making varnish, to pick out pure 
and transparent amber, but only the common yellow 
small fragments, which may be procured for half the 
price of that in lumps. The earthy part, which is found 
in amber not of the clearest kind, separates itself from the 
warm varnish when it is suffered to stand some time be- 
fore it is decanted. 
