26 JOURNAL OF THE 
the tetrabromide with water and also by dissolving zirco- 
nium hydroxide in hydrobromic acid (Gmelin, Handbook, 
6th ed’n. Il. 1. 7060.) It crystallizes from the aqueous 
solution in fine transparent needle like crystals contain- 
ine water of crystallization (Melliss, Mats Weibull B. 
1887. 1394). 
Weibull gives the following analyses: 
Calc. ZrOBrg.8H2O 
Zr 20.35 20.83 21.87 
Br 41.16 38.70 39.05 
He says that the crystals are isomorphous with those 
of the oxychloride which seems to be true. They are 
much more hygroscopic. His two analyses are decidedly 
discordant and one would judge that the amount of water 
of crystallization had been decided upon from the analogy 
to the oxvchloride. 
The oxy-bromides described in the following experi- 
sents belong to two types with varying degrees of hy- 
dration—ZrOBr, plus x H,O. where x equais 3, 13, or 14 
and ZrBr(OH), plus yH,O where y equals 1 or 2. All of 
these compounds are deliquescent and decompose on ex- 
posure to moist air, the clear white crystals, often col- 
ored pink by free bromine present, melting to a eum, 
frequently with the evolution of hydrobromic acid. ‘The 
salts are unstable even in dry air as was found on expos- 
ine dried crystals upon a watcheglass in a desiccator con- 
taining suiphuric acid. Much hydrobromic acid was 
evolved in the decomposition. 
The crystals were prepared in two ways:—either by 
dissolving pure Zr(OH), in dilute hydrobromic acid evap- 
orated upon water bath with subsequent additions of 48 
per cent. hydrobromic acid and repeated evaporations, or 
a concentrated solution of hydrobromic acid was saturated 
with Z1(OH),, evaporated and the crystals obtained on 
cooling. 
As a rule the crystals obtained were quite soluble in 
the hot acid but separate at once on cooling. In the 
heating necessary tor the thorough saturation of the hy- 
