88 T. 8S. Hunt on Lime and Magnesia Salts. 
just cited. The power of alkaline chlorids and of chlorid of 
calcium to prevent the precipitation of carbonate of lime, an 
even to dissolve it when precipitated, has already been observed 
by Berthollet and by Storer (Dictionary of Solubilities, 110), 
but the inquiry does not appear to have been pursued farther. 
In like manner the power of salts of potash, soda or magnesia to 
prevent the precipitation of magnesia by alkaline carbonates, was 
noticed by H. Rose and by Longchamp (Gmelin’s Handbook, iii, 
225). These reactions | have made the subject of careful ex- 
periments, one object of which was to determine whether hy- 
drated or anhydrous double carbonates of lime and magnesia 
of calcium are first mingled, is immediately dissolved by a solu- 
tion of sulphate of magnesia, and by operating with solutions 
of known strength, as indicated above, it is easy to obtain trans- 
parent liquids holding in a liter, besides three or four hundredths 
of hydrated sulphate of magnesia, 08 gr. and even 1-2 gr. of 
carbonate of lime, together with 1:0 gr. of carbonate of magne- 
sia, the only other substance present in the water being the chlo- 
rid of ium equivalent to these carbonates. <A solution of 
chlorid of magnesium, holding some chlorid of sodium and sul- 
hate of magnesia, in like manner dissolved 1:0 gr. of carbonate 
of lime to the liter. Such solutions have an alkaline reaction. 
t 
rod), and at the end of eight or ten days at the ordinary temper- 
ature the solution holds no more lime in solution, although still 
