81 
On decomposition with hot water a small quantity of 
chlorine is invariably retained by the tungstic acid formed, 
even after repeated distillation with water. Hence it was 
necessary in the analysis to reduce the oxide to metal and 
to collect the hydrochloric acid formed. This was effected 
by covering the weighed chloride in a porcelain boat with 
water and bringing it into a bent combustion tube, one end 
of which was connected with a hydrogen evolution apparatus, 
and the other with a flask of water in which the acid was 
collected. On gently heating the fore part of the tube (the 
greatest care being taken to prevent spirting) the chloride 
is converted into the yellow oxide, after which it was more 
strongly heated and the reduced metallic tungsten weighed 
whilst the chlorine was estimated with silver. 
Six analyses of different material, prepared on different 
occasions and according to different methods, yielded the 
following results : — 
Calculated. 
Found. 
Tungsten W ... 
... 184 .. 
.... 46-35 .... 
.. 46-49 
Chlorine Cl 6 ... 
... 213 .. 
.... 53-65 .... 
.. 53-32 
397 
100-00 
99-81 
The exact determination of the melting point of the 
hexachloride is attended with some difficulty, as the liqui- 
faction takes place gradually and the smallest traces of 
impurity depress the melting point down to about 180° C, 
that given by the older observers. A mean of several 
experiments gave the number 275° C (corrected) as the 
melting point and 270° as the point of solidification. The 
constant boiling point of the hexachloride was found to be 
346 - 7° (corr.) under 759 - 5 mm. of mercury. The vapour 
density of the hexachloride was determined (1) in sulphur 
vapour at 440°, and (2) in mercury vapour at 350°. As the 
hexachloride always leaves on distillation a small quantity 
of solid residue, the substance was distilled (either in a 
current of carbonic acid or of chlorine) into the heated bulb 
