( 337 ) 
calculated, assuming the residue to be the monohydrate”, without 
proving that this was really the case by separate experiments [| 
first made sure of this point. 
a. Of a solution containing 57.20 grams of ZnSO, to 100 grams 
of water, 5.9390 grams were evaporated. 
The weight of the residue after 24 hours was 2.3986 grams. 
Assuming that the composition of the residue was ZnSO,.1 1,0 
the original solution must have contained 57.20 grams Zn SO, to 
100 grams of water. 
After remaining seven days and nights on the water bath the 
Zn SO,.1 HO lost 3,8 mgrms., or 1/, pCt. of its weight. 
b. Of a solution containing 65.84 grams of Zn SO, to 100 grams 
of water, 6.9124 grams were evaporated. 
After 16 hours the residue weighed 3.0506 grams. 
From this 65.84 grams Zn SO, to 100 grams water is calculated. 
After remaining for eight days and nights on the water-bath the 
residue had lost 4 mgrms. or 1, pCt. of its weight. 
The method adopted is therefore quite trustworthy. 
All the measurements were made with the temperatures rising, 
that is to say the salt and water were maintained for a long time 
at a lower temperature than that at which the solubility was to be 
determined. This was necessary since I had observed that the very 
viscid solutions readily remain in a supersaturated condition. 
di: VE Lin eG 
Solubility of ANSO. m0. | Solubility of Zn SO,. 6 H,O. 
Ist Deter- | 2nd Deter- E wi Ist Deter- | 2nd Deter- 
Temp. 
= 
bd . . . 
mination. | mination. = mination. | mination. 
BARNES 
CALLENDAR 
and 
BARNES 
CALLENDAR 
and 
gel 47.11 47.C7 | 47.09) 46.96 — 54.20 54.20 — 
1596 50.83 50.94 | 50.88) 50.74 57.09 57.20 57.15) — 
25°.0 57.04 57.87 57.90) 57.95 63.74 — 63.74) 63.74* 
80° .0 — — — 61.92 65.50 65.84 65.82| 65.65* 
35°.0 66.59 66.63 66.61} 66.61 67.99 — 67.99| 67.94* 
— 5° 39.33 39.27 | 39.30) — 47.08 — 47.08; — 
0°.1 41 . 94 41.92 | 41.93) 41.85 49.53 49 . 44 49.48) — 
-— 70.08 70.08} 70.02* 
39°.0 70.00 70 09 | 70.05) 70.05 
All the figures are grams of Zn SO, in 100 grams of water. 
24* 
