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IOWA ACADEMY OF SCIENCE 
groups. Lead was determined by direct ignition in the crucible 
as the sulphate. 
.2000 g. of the lead salt gave .0200 g. water and .1154 g. PbSO^. 
Theory for CsH 50 ,NSPb. 3 H 20 Found 
Water, 10.38 per cent. 10.00 per cent. 
Lead, 39.8 per cent. 39.45 per cent. 
Acid Potassium Salt. 
NOs • CH3 • CeHs • SOsK • COOH • H^O 
This salt has been prepared in two ways; either by precipi- 
tating the silver from the silver potassium salt by dilute hydro- 
chloric acid, evaporating and crystallizing; or by recrystallizing 
the neutral potassium salt from very concentrated hydrochloric 
acid. In the latter case, unless the hydrochloric acid is strong 
in the solution, the neutral potassium salt crystallizes out again, 
probably on account of its lesser solubility in water. The acid 
potassium salt once formed, however, can be recrystallized from 
water without decomposition. It comes out of the solution in 
beautiful fine needles containing one molecule of water of crys- 
tallization. 
.1863 g. potassium acid salt gave .0107 HoO and .0490 g. K 2 SO 4 . 
.2258 g. potassium acid salt gave .0600 g. K 2 SO 4 . 
.3061 g. potassium acid salt neutralized 8.9 cc. .10676N NaOH. 
Theory for CsHsOtNSKHsO Found 
Water, 5.67 per cent. 5.74 per cent. 
Acid hydrogen, 0.315 per cent. 0.317 per cent. 
Potassium, 12.33 per cent. 11.81 - 11.92 per cent. 
The Free Acid. 
NOg • CH3 • CeHs • S63H • COOH • SHgO 
The free acid was prepared from the pure neutral silver salt 
by adding just a trifie more than the calculated amount of 
0.1 N hydrochloric acid to the water solution of the salt, boiling, 
filtering, and evaporating to a small volume. The acid crys- 
tallized from water in platelike needles strongly rosetted and 
easily broken. It had only a slight yellowish tint. It was in- 
soluble in ether, ligroin, and carbon tetrachloride. It was sol- 
uble in acetone, ethyl acetate, or glacial acetic acid. Its melt- 
ing point when it was crystallized from acetone or alcohol was 
