m 
held in the proper light, that peculiar ramified appea¬ 
rance shown by frost on window panes. 
In some parts of the wood are what appear to he 
minute granules of this resin mixed with woody matter, 
but when examined under the microscope they prove to 
be small crystals, with their faces obliquely inclined to 
one another. I did not succeed in finding any large and 
regular enough for determining the crystaline form. 
But this substance is not confined to the annual 
layers; for if the wood is split in any direction what¬ 
ever, numerous shining points appear > showing that it 
is completely saturated with it. 
In order to obtain this from the wood the latter is 
finely cut up with a turning lathe, or by any other 
convenient means, and then boiled in ether for several 
hours. The extract is then poured off, fresh ether 
is added, and again submitted to two or three hours 
boiling. The two extracts are now poured together and 
considerably concentrated by distilling off* a part of the 
ether. Strong alcohol is added to this till all remains 
dissolved. 
From this it was found impossible to obtain crystals, 
although, exposed to a temperature below 0° C., a red¬ 
dish oil went down instead. 
So in order to separate the resin from other or¬ 
ganic bodies, which were presumed to be present, and 
which were supposed to prevent the forming of crystals, 
the acetate of lead was added. The large and heavy 
precipitate, which went down, was thrown on to a filter, 
and the filtrate, after being freed from the excess of 
