ELISHA MITCHELL SCIENTIFIC SOCIETY. pas 
Summarizing our examination of these oxychlorides 
then, we find that there are three. 
1. An oxychloride gotten in large, well-formed crystals 
by crystallization from water. These crystals lose 
slowly both water and hydrochloric acid on exposure to 
the air. Their formula is ZrOC1,.8H,O. 
2. An oxychloride gotten by precipitation by hydro- 
chloric acid from an aqueous solution. This is insoluble 
in hydrochloric acid. It is seen in silky crystals or a 
white mass of very fine crystals. The formula is 
ZrOCl,.6H,O. 
3. An exychloride gotten by crystallization from hy- 
drochloric acid. This has the formula ZrOCl1,.3H,O. 
When any one of these is dried at 100—125° with a 
stream of dry hydrogen chloride passing over it three 
molecules of water of crystallization are left and the oxy- 
chloride has the formula given under 3. namely ZrOCl.. 
3H,O. These last molecules of water are lost at a tem- 
perature of 180—210°. 
Weibull (Ber. 1887. 1394) gives the measurements of 
the crystals of the oxychloride formed from water. They 
belong to the tetragonal system, are optically unaxial 
with double refraction. 
Several times during the examination of these oxychlo- 
rides the formation of a hvdrogele was observed. ‘The 
exact conditions under which it was formed were not de- 
termined. ‘The tendency to form this hydrogele is much 
less than in the case of the bromides and iodides. Similar 
compounds will be mentioned there. 
III. ZIRCONIUM BROMIDES. 
Zirconium tetrabromide, ZrBr,, is formed by conducting 
bromine vapor over a heated mixture of zirconium and 
carbon. A stream of carbon dioxide may be used tor 
carrying the bromine vapor. It forms a white crystalline 
(microscopic) powder which can be sublimed but is de- 
composed by water, (Melliss J. 1870. 328:). 
Zirconium oxybromide may be formed*by decomposing 
