28 
CHLORINE AND BROMINE COMBINATIONS. 
The rational formula for any one of the fossils which 
we have mentioned has not yet been determined. 
We only know the empirical formula. None of the 
products resulting from their combination with chlorine, 
bromine, sulphuric or nitrous acids have been analyzed. 
For this purpose we have formed and analyzed se¬ 
veral chlorine and bromine combinations of this resin. 
Chlorine gas was passed over a few grams of it as 
already described, for the space of one half hour. It 
was then dissolved in alcohol and ether, and stood in 
the cold to crystalise. After standing several days, all 
the undecomposed resin crystalised out, and soon a clear 
transparent oil began to go down. 
The mother liquor was now poured off, and another 
attempt was made to crystalise this oil from its solution 
in alcohol and ether; but though exposed for many 
nights to a temperature several degrees below 0° C., 
still no crystals were formed, but this oil appeared again. 
The mother liquor was allowed gradually to evapo¬ 
rate till the clear colorless oil, which was sent down, 
began to be of a somewhat yellowish tinge. From this 
the mother liquor was poured off, and the oil redissolved 
in alcohol and ether, and again allowed to evaporate 
till two thirds of that which had been dissolved was 
precipitated. This was perfectly clear, transparent, and 
colorless. The mother liquor was again poured off, and 
the oil again treated with alcohol and ether. 
It was then transferred to a watch glass, — put under 
the air pump, together with pieces of caustic potash, — 
