— 8i — 
acid hv M/i l acid , and to separate the silicic 
acid by evaporating- to dryness and heating in an air 
bath at 115 to 120 degrees for two hours, after which the 
mass was wet with strong hydrochloric acid and evaporated 
as n r X eS |! T 111 } T t ! 1C wat , cr ' bath > taken up with water and 
as 1 ttle hydrocholoric acid as possible, and the solution 
from 6 the l ° 2 ^° C ' T be i° luble sd ' c ‘ c acid was separated 
ti “™ th e sand and carbon by means of caustic potash solu- 
tion. 1 he sand, etc., was washed from the filter into a 
platinum dish, a solution of caustic potash, corresponding to 
three grams of the solid salt, was^ added, and the whole 
evaporated to dryness on the water-bath. This gives us 
fixed conditions tor all the analyses. Fresenius and Will 
tinnc Sh mT n that sand ls dot attack ed under these condi- 
nnaTwed f DOt enOU « h in an y Sam P le of a ®h 
analyzed to give any trouble and the solutions were clear 
and colorless. The residue, insoluble in caustic potash, was 
ntilfreef, hydr , ochloric a ^ d and subsequently^* water 
until free from chlorine and weighed on a tared filter. The 
acid b °waI aS Ur r , anC L the Sand we *shed. The silicic 
weilhTdjseparated from the potash solution as usual and 
? u S S1 lca * One portion of the solution, correspond- 
one , g , ran ? of ash > was taken from the determi- 
nation of the sulphuric acid, oxide of iron, and alumina. A 
second portion, equal to the first, was taken for the phos- 
p tone acid, manganic oxide, lime and magnesia, and a 
-hird_ one for the determination of the alkalies. The sul- 
anunc acid was thrown down as baric sulphate from the 
DOiling solution by hot dilute baric chloride solution • this 
precipitate was hkered off, washed until no chlorine could 
veithl^ T, m the r ash r wat , er > .ignited, and as a precaution, 
veighed. It was then fused with sodic carbonate or sodic- 
lotassic carbonate—the solution of the sulphate must be 
omplete—whereby the excess of barium and any iron and 
1 uminais separated, the solution was acidulated with hy- 
oc one acid and after standing until the excess of car- 
>onic oxide had escaped, was heated to boiling*, and thesul- 
'hunc acid again precipitated by a hot dilute solution of 
Jfnc chloride; this precipitate was washed and weighed, 
hen dissolved in concentrated sulphuric acid, and the 
anc sulphate cystallized by evaporation to dryness and 
with the alkaline 
onates, is advisable to remove excessive baric salts, iron 
nd alumina, the solution in sulphuric acid to remove alka- 
ne salts from the baric sulphate. These operations 
-ng en the analyses, but the results are very different 
-om the first weights obtained in the determinations. 
