170 T. E. Clark on Fichtelite from North Bavaria. 
To another portion Nordhausen acid was added, and then 
heated in the water-bath. Sulphurous acid was slowly given 
out, and the solution became deep red. In order to see if any 
combination with sulphuric acid had taken place, water was 
added and the whole heated with carbonate of baryta. The 
precipitate was separated, but the filtrate, which was greatly 
concentrated by evaporation, yielded no crystals of any soluble 
salt of baryta. 
This experiment was often made in different ways, but with: 
out obtaining any combination with sulphuric acid. 
To another portion of this resin fuming nitric acid was added, 
and heated carefully in the water-bath. Soon a violent reaction 
took place, red fumes of nitrous acid were given out in large 
quantity. After the action of the nitric acid was finished, the 
whole was evaporated to one-third its volume, and water added, 
eausing a white precipitate. This was thrown on a filter, 
washed out, and dissolved in aleohol and ether. The reddis 
solution was boiled with animal carbon to decolorize it, and then 
exposed to a temperature several degrees: below 0° C. But in 
stead of crystals being formed, an oily substance, which proba- 
bly holds nitrous acid, was s 
The filtrate of the precipitate caused by the action of water on 
the nitric acid solution, was evaporated to dryness over the 
water-bath ; the residue was found to contain oxalic acid. 
If this resin is thrown into cold fuming nitric acid and allowed 
to stand for two or three days, it dissolves entirely; but when 
precipitated from this solution by water, and dissolved in aleohol 
and ether, it behaves like the last, going down as a reddish oil. 
A mixture of fuming nitric and sulphuric acids seems to act like _ 
nitric acid alone. teh 
Although we have not succeeded in obtaining combinations 
With nitrous acid, which we know to be such, yet we do not 
doubt but that they are formed, from the fact that they have 
Se obtained from other substances which are very similar t0 
is, : 
- 
the melted substance; or two or three compounds may be 
formed at the same time. Fumes of hydrochloric acid appeat 
at the open end of the tube. 
