TWENTY-NINTH ANNUAL MEETING. 85 
Determination of Lime.—The filtrate from the above is treated with am- 
monium oxalate, boiled, allowed to remain in a warm place for several hours, 
then filtered, washed, and the residue dried, ignited, and weighed either as car- 
bonate or oxide. 
Determination of Magnesium.—The filtrate from the above is evaporated 
to dryness with some nitric acid. If the residue is very large it is redissolved in 
nitric acid on an iron plate; then the residue is treated with cold water and a 
drop of HCl; filter if necessary, and add to the solution hydro-di-sodium phos- 
phate and ammonium hydrate and allow the precipitate to stand several hours. 
The precipitate of ammonium-magnesium phosphate thus obtained is washed 
with dilute ammonia, and after drying is weighed as magnesium pyrophosphate. 
Determination of Sulfuric Acid.—Acidulate one liter of water with HCl, 
and concentrate to about 200 c. c., add BaCle and allow to stand for some time 
in a warm place. The BaSOx; is weighed as such, and the sulfuric anhydride is 
calculated from this. 
Determination of NazO, K20, and Liz0.— The filtrate from the barium 
sulphate is evaporated to dryness in a platinum dish to remove HCl and separate 
silica. Digest the residue with a few c. c. of water, and precipitate magnesium 
without previous filtration by addition of a solution of Ba (OH )s, avoiding a large 
excess. Enough has been added if a pellicle of barium carbonate forms upon the 
surface of the liquid on exposure a short time to the air. Filter and wash the 
usually slight precipitate ; heat the filtrate, and add ammonium carbonate, and 
evaporate the filtrate to dryness, and remove by heating the ammonium chloride 
completely. Dissolve the sodium chloride in the residue with four or five ec. c. 
of water; warm, and adda few drops of ammonium carbonate and ammonia to 
separate possible remaining traces of barium, magnesium, and calcium;; filter 
again into a weighed platinum dish, evaporate to dryness, heat nearly to fusion, 
and weigh the mixed chlorides. Their residue will contain, besides sodium chlo- 
ride, the potassium chloride, if any is present in the water. If enough alkali is 
obtained, it may, after weighing, be examined for potassium by ordinary methods. 
Determination of Sodium Carbonate.— Evaporate one liter of the water to 
dryness on a water-bath, treat with water, filter, wash until filtrate no longer 
shows an alkaline reaction with litmus paper, and titrate the solution with stand- 
ardized sulfuric acid. The result is calculated to sodium carbonate. 
Determination of Bromine and Iodine.—These were determined according 
to the method as given in the Journal of the American Chemical Society, Vol. 
18, August, 1896, page 688. This is a modified method, and the writer used it 
with good success. 
A number of waters have been examined by the above methods. The most 
important of these are the following: 
ie 
Water from Girard, Kan., used as a source of city supply ( parts per 100,000) : 
SHOU BLE) oso... SAK WE Poy deh, danced MAID 
Hes@xa iN lsOgre a eee Jee he oes AP 25 
CaO eg x 12155 
MgO. ee 5.70 
INGO) SCs aes tn: 2. eee 38.75 
NasCOs Seo Soe 5) ig: 
SOs . 80.68 
Ce 3g SB Oe c/o 5 Ae URE EN Ie rn 40.25 
COs, undetermined. 
