450 T'ransactions,— Chemistry. 
The water proved to be not only a hard water in the sense of being very 
calcareous, but highly chlorinated too,—that is, one containing an alkaline 
chloride in quantity, and this fact viewed in conjunction with that of the 
imperfect operation of Clarke’s process upon it led me to suspect that 
these chlorides can exercise a very decided solvent effect upon mono- 
carbonate of lime. That they have this effect was clearly shown by an 
investigation I carried out, and the result of which I now beg to lay before 
you as follows. First let me give an may of the hard water :— 
Chloride of sodium ; x s 2. ADSIT 
Sulphate of soda . kė a c em uc PUT 
magnesia i 2 ši s .. 50 
Bi- Sables of magnesia .. e+ xs SE E uu 
lime i? i ii S ss 10:82 
Silica M T s s ss m ix D 
44-62 
On behalf of any here who may have forgotten the mode in which 
Clarke's softening process effects what is desired of it, I will shortly describe 
it, as it is necessary to remember it in order that the bearing of the 
several statements to be made here may be fully apprehended. 
This process then consists in applying lime-water to the water to be 
softened, by which all the lime existing therein in the form of bi-carbonate 
is brought into that of the mono-carbonate, and this compound being far 
less soluble in water than the original one, is in greater part precipitated. 
The full meaning of the effects I proceed to state will now be readily 
gathered. 
1.—A saturated aqueous solution of sodic chloride was mixed in equal 
volume with a strong solution of bi-earbonate of lime, and Clarke's soften- 
ing fluid was added thereto in varying quantities until quite in excess. The 
liquid remained quite clear, and no precipitate formed in twenty-four hours. 
2.—The same effects followed when either potassie or calcic chloride, 
potassie nitrate or sodic carbonate were substituted for the sodic chloride 
in experiment No. 1 
8.—The Oamaru hard water was mixed with sodic aniohide atthe rate 
of one pound to the gallon; the filtered solution when treated with lime- 
water in small or large quantity remained quite clear. 
4.—The same water was charged with a slight excess of lime-water 
alone (sodie chloride being this time omitted) when an abundant preci- 
pitate formed. This precipitate, when analyzed and the results computed 
in grains per gallon upon the water erus gave as follows :— 
Carbonate of lime >s 4D 
Carbonate of magnesia  .. m + RS ks "81 
22:56 
Ese nein E Nu tane 
