As fast as the
ore is drawn out from the retorts the elevator supplies a new
lot, so that the retorts are always filled, thus making the
process continuous."
The temperature of the charge in the deoxidizer is from 800 deg. to 1,000 deg.
F.--_Amer. Engineer._
* * * * *
SOME REMARKS ON THE DETERMINATION OF HARDNESS IN WATERS.
By HERBERT JACKSON.
Having had occasion some short time ago to examine a hard water which
owed half its hardness to salts of magnesium, I noticed that the soap
test, applied in the usual way, gave a result which differed very much
from that obtained by the quantitative estimation of calcium and
magnesium. A perfectly normal lather was obtained when soap had been
added in quantities sufficient to neutralize 14 deg. of hardness, whereas
the water contained salts of calcium and magnesium equivalent, on
Clark's scale, to a hardness of 27 deg..
Although I was aware that similar observations had been made before, I
thought that it might be useful to determine the conditions under
which the soap test could not be depended upon for reliable results.
I found with waters containing calcium or magnesium alone that,
whenever salts of either of these metals were in solution in
quantities sufficient to give 23 deg. of hardness on Clark's scale, no
dependence could be placed upon the results given by the soap test.
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