ELISHA MITCHELL SCIENTIFIC SOCIETY. 29 
hydrobromic acid not removed, for thirty minutes should 
have been allowed for the removal of all the acid as 
was found in the work on the oxychlorides we have: 
Found Cale. for ZrOBry.4H20. 
ZrO 36.31 36.21 
Br 47.80 47.30 
Of course such a calculation is not allowable and 1s 
given merely to show the possible composition of the 
dried mass. The experiment was not repeated on ac- 
count of expense as to both time and materials. 
One hundred cubic centimetres of 48 per cent. hydro- 
bromic acid solution were saturated with Zr(OH), by con- 
tinuous boiling. The volume reached at least 500 cubic 
centimetres before the hydroxide ceased to be taken up. 
The solution was never perfectly clear until it was twice 
filtered through compact filter paper doubly folded. The 
clear yellow solution was concentrated by evaporation on 
the water bath. The more concentrated 1t became the 
redder it was, finally the color was so deep that it ap- 
pearea almost black. This was due’ to decomposition of 
the hydrobromic acid by organic dust in the air no doubt. 
After concentration the liquid was cooled and white 
crystals separated out. On allowing it to stand 24 hours, 
or always when made too concentrated by further evapo- 
ration, a red jelly separated on top the crystals. In trying 
to wash this red jelly from around the crystals, for it was 
very soluble in water, the crystals were also dissolved. 
The whole was therefore redissolved and after several 
attempts a set of prismatic needles 1—2 millimetres in 
length separated out free from the jelly. This jelly was 
not silicic acid as feared. The mother liquor was poured 
off, the crystals quickly washed three times with small 
amounts of water, dried between filter paper and anal- 
yeu. — 
Found Calc. for ZrBr(OH)32H,O 
ZrO». 34.90 34.434 35.23 
Br 30:79 31.01 
The solution was further evaporated and another crop 
