354 J. W. Mallet on the Atomic Weight of Lithium. 
sheet of platinum, and the fused mass broken up while warm, 
and quickly enclosed in a bottle with a well ground stopper. 
and absolute alcohol. 
‘on in an uncovered vessel for some time the salt loses 
a little chlorine, and takes up oxygen, so that when redissolved 
in water it reacts alkaline to test-paper; but it was found that 
this change could be completely svolmed by mixing a little pure 
sal-ammoniac with the chlorid of lithium before evaporation to 
ess, and fusing the dry mass in a covered crucible. The 
heat obs must not be too great until the sal-ammoniac has 
been driven off,—as in a first experiment, in which the quantity 
of NH.Cl was considerable io the heat rapidly applied, the 
ter part of the chlorid of lithium was velatilined and lost, 
although the platinum crucible was covered and was not raised 
to more than a low red heat. 
= Having got then pure fused chlorid of lithium, it remained 
to determine its composition or the per-centage of chlorine which 
it contains. The salt is a deliquescent one, and it seemed doubt- 
ful at first whether the absorption of moisture could be pre- 
vented during weighing, but it was found that in a platinum 
rege provided with a tightly fitted cover, the portion taken 
remaining constant for more than five minutes in the hot 
atmosphere of a summer day. The balance used was an exc’® 
lent one of Berlin make, permitting of accurate weighing to the 
one-tenth of a milligramme. Both it and the weights used were 
subjected to a careful examination as to adjustment beforehand. 
Three or four pieces of the fused chlorid of lithium were 
fused cake, could be weighed with ease and certainty ; the wy 
: as | 
serve perfect correspondence between the two weighings. The 
i beaker 
crucible 
was once more heated, cooled, and weighed; its weight Dow 
being subtracted from the former weighing gave the amount of 
LiCl used. The solution of LiCl was precipitated by @ 
