148 Scientific Preceedings, Royal Dublin Society. 
ath until its contents were completely dry. ‘To the dry residue 
another e.c. of strong hydrochloric acid was added, the mixture 
lieated for a minute or two on the water-bath, and then washed 
through a small filter—the washing being continued until no 
residue was left on evaporating a drop on a slip of glass. The 
filter and its contents were then dried, ignited, and weighed. 
Crucible, plus Si02 =. : : . 21-9181 grms. 
95 alone, : : és 5 WISI 5. 
$i0: => *0057 9 
The washings were mixed with 1 c.c. of dilute sulphuric acid 
(1:3), and evaporated to small bulk on the water-bath. The 
sulphate of barium was then filtered off and washed, first with 
strong hydrochloric acid, and finally with distilled water, until a 
drop left no residue on evaporation. Dilute ammonia was now 
added to the filtrate and washings until the mixture was faintly 
alkaline, when it was evaporated to dryness, re-dissolved in water, 
one drop of dilute ammonia added, and the ferric oxide and 
alumina filtered off, washed, ignited, and weighed. 
Crucible, plus Fe203 and AlzO3, . . 21°9136 grms. 
+3 alone, 5 a . 5 ORI oA. 
Fe203 and AlsO3 = 0014 > 
To the filtrate a drop or two of ammonium oxalate was added,,. 
and it was then evaporated to small volume, but no precipitate 
appeared, so the absence of lime was concluded. Finally, the 
solution was evaporated to dryness and calcined, the residue re- 
dissolved, filtered, and once more evaporated to dryness with a 
few drops of dilute sulphuric acid, and again calcined at a bright 
red heat, and afterwards weighed. 
Crucible, pus alkaline sulphates, - - 21-9160 grms. 
35 alone, . é E 5 5) PALSIEM 56 
Alkaline sulphates, -0040 
The action of the baryta water on the glass of the Winchester 
quarts was thus shown to consist (partly at all events) in the 
removal from it of silica, alumina, and ferric oxide, together with 
alkalies,’ all of which passed into solution. 
* The original barium hydrate had been twice recrystallized, and all evaporations- 
were performed in platinum vessels. 
