Analysis of the Chalybeate Spring at Thetford. 363 
Exp. 3.— When the water of the spring had been boiled, it 
did not produce this reddening effect with blue tincture of litmus. 
Exp. 4.—Six cubic inches of lime-water added to ten of the 
water of the chalybeate spring, produced a white precipitate, 
which disappeared by the admixture of muriatic acid. 
Exp. 5.—Crystallized hydrate of barytes produced a copious 
precipitate both in the fresh water, and in such as had been con- 
centrated by evaporation. The precipitate was not soluble in 
muriatic acid. 
Exp. 6.—Oxalate of ammonia produced much cloudiness both 
in the fresh and in the boiled water. 
Exp. 7.—Nitrate, sulphate and acetate of silver produced in 
the fresh and in the boiled water much cloudiness—which did 
not disappear by the addition of nitric acid. 
Exp. 8.—Two grains of acetate of barytes rendered eight cu- 
bic inches of the chalybeate water turbid. The filtered fluid af- 
forded with acetate of silver a copious precipitate. 
Exp. 9.— Tincture of galls produced with the fresh water a 
purple hue. Water concentrated by boiling was not affected 
by this test. 
Examination of the gaseous Contents of the Water. 
Nine hundred and twenty-four cubic inches of the chalybeate 
water were introduced at the fountain head into a retort con- 
nected with a mercurial pneumatic apparatus. The water was 
made to boil, and the gaseous products collected in the usual 
manner. 
After the apparatus had again acquired the common tempera- 
ture, barytes water indicated 48-28 cubic inches of carbonic acid 
gas, of which 12-7 are contained, therefore, in one gallon of the 
water. 
The residuary gaseous fluid, on being examined by the test of 
phosphorus, was found to be composed of 1°21 of oxygen and 
3°04 atmospheric air. 
Analysis. 
Exp. \1.—Four gallons of Thetford chalybeate water being 
evaporated in an earthenware vessel, placed in a baker’s oven, to 
dryness, afforded a brown mass of a slightly saline taste. 
Exp. 2.—This product was levigated and digested in alcohol 
filtered, and the insoluble residue put aside for further exami- 
nation. The alcoholic solution mingled with a small quantity of 
water, became turbid by the addition of sulphate of silver ; and 
phosphate of soda in combination with carbonate of ammonia 
produced with it much cloudiness. 
Exp.3.—The mass which had been repeatedly acted on by al- 
cohol was boiled first in eight parts of water, and this solution was 
put 
