' SL. Penfield—Descloizite from Meaico. 363 
carbonate, the fusion soaked out in water and the oxide of iron 
thus separated and weighed. The soluble part of the fusion 
contained both vanadic and phosphoric acids. To the dilute 
acetic acid solution containing the vanadium and zine, lead acetate 
was added which precipitated all the vanadium as a basic lead 
vinadate. This precipitate was washed with hot water and 
ried; it was then transferred to a beaker, the paper burned 
and the ash added; the whole was then dissolved in nitric 
acid, sulphuric acid added to precipitate the lead and evapo- 
rated till nitric acid was expelled. The vanadic acid was then 
dissolved in water, filtered from the insoluble lead sulphate, 
evaporated in a weighed platinum dish and after expelling the 
sulphuric acid and strong ignition, weighed as pentoxide. As 
regards the purity of the vanadium pentoxide obtained by the 
above method the following can be said. It was completely 
soluble in aqueous ammonia and the solution when transferred 
to a weighed platinum crucible and evaporated and ignited 
Save results agreeing with the weight obtained by weighing in 
an Open platinum dish. The pentoxide was reduced to the tri- 
oxide by igniting in a current of hydrogen gas and gave in two 
cases a loss of oxygen equal to 16°86 and 16-98 per cent of the 
pentoxide employed. Vanadium pentoxide with molecular 
weight 192-4 should give by reduction to the trioxide a loss o 
OxXygen equivalent to 17°54 per cent. 
The zine which remained in the filtrate from the basic lead 
vanadate was precipitated, along with the excess of lead used 
a8 a precipitant, from the acetic acid solution by means of 
hydrogen sulphide. The sulphides after settling were collected 
‘on a filter, washed and dried; they were then transferred to a 
dry beaker, the filter paper burned and the ash added ; to this 
Strong nitric acid was added with enough sulphuric acid to 
combine with the bases, and the whole evaporated till sulphuric 
acid fumes began to be given off. After cooling and addition 
of water the soluble zine sulphate was separated from the lead 
sulphate by filtration. The zine was then precipitated as basic 
zine carbonate by means of sodium carbonate with the usual 
precautions, washed and weighed as oxide. The zine oxide 
was in all cases tested and found to be free from vanadium. 
Phosphoric acid was determined in a separate portion by 
means of ammonium molybdate. The first precipitate seemed 
to be impure; it was therefore dissolved and reprecipitated with 
ammonium molybdate before its solution in ammonia and pre- 
Cipitation with magnesia mixture. 
Water was obtained by igniting a weighed portion of the 
mineral to low redness and calculated from the loss of weight. 
'O guard against any inaccuracy another determination, analy- 
sis IIT was made by igniting in a Bohemian glass tube and col- 
