B04 
practically a constant weight. A final trial of the effect upon the weight 
of rubbing simply with the finger was made. The crucible lost .0039 grams. 
SUMMARY OF ADVANTAGES. 
(1) The crucible was used to advantage in determining Cu as CuSCN, 
Ba as BaSO, and Ag in AgCl when HCl was used as the precipitating agent. 
(2) Manipulating was found to be surprisingly simple and rapid when 
an analysis was once under way. 
(3) Nearly a constant weight was maintained by the crucible if not 
heated over 140° when washed with water. 
SUMMARY OF DISADVANTAGES. 
(1) It was found difficult at best to wash precipitates free from pre- 
cipitating agent, especially if the latter should be left as a solid residue upon 
evaporation of the solution. 
(2) Suction was necessary, and, in the case of AgCl,NH,OH, to thor- 
oughly cleanse the crucible. 
(3) It was found unadapted to filtration of such gelatinous precipi- 
tates as Al(OH);. 
(4) Heating six or eight times in the blast lamp was sufficient to render 
the crucible so brittle as to be broken even by suction, and a consistent loss 
in weight was observed. 
(5) In three cases the first use of crucibles led to results greatly in 
error. 
(6) Abrasion or friction was found to have a marked effect upon the 
weight of the crucible. 
(7) The ordinary digestion of fine precipitates to be filtered was not 
avoided when it was used. 
Like the Gooch crucible therefore, the Alundum crucible apparently 
has only a limited field of usage but within that field it should be of consider- 
able worth to the analyst. 
