64 T. S. Hunt on Lime and Magnesia Salts. 
§ 103. The following experiments were made in confirmation 
of those described in 1859. In the examination of the products 
obtained, acetic acid was made use of as before, but with modifi- . 
cations ($78). A dilute acid was prepared by mixing three 
measures of the glacial acid with ninety-seven of water. Of 
this liquid, containing three-hundredths of acetic acid, there 
would be required in round numbers about 44 c.c. for the solu- 
tion of one gram of dolomite, upon which the action is compar- 
atively slow at the ordinary temperature, although this same 
liquid dissolves carbonate of lime with lively effervescence. By 
dividing into two or more portions the amount of this dilute 
acid required to dissolve a given weight of a preparation of thé 
two carbonates, and keeping separate the matters dissolved by 
the successive portions, a fractional analysis of the material is 
effected, which gives results still more satisfactory than those ob- 
tained by the method described in the previous paper. 
§ 104. In § 37 it was shown the anhydrous crystalline car- 
bonate of magnesia evinces no disposition to combine with car- 
bonate of lime, and the following experiments will show that 
the crystalline sexhydrated carbonate of magnesia (§ 87) is but 
little disposed to combination. A portion of this compound 
was intimately mingled with an equivalent of precipitated car- 
nate of lime and one-fifth of an equivalent of bicarbonate of 
soda, which would at an elevated temperature furnish carbonic 
acid that might aid the reaction of the earthy carbonates. This 
mixture formed into a paste with water was heated in a closed 
tube for two hours from 120° to 180° C., and then to 180°C. 
After six hours the matter was removed, washed with water and 
magnesia, while the residue was slowly but completely soluble 
in hydrochloric acid, and was carbonate of magnesia with only 
3°2 p.c. of carbonate of lime. From this it appears that a por- 
tion of the double carbonate is formed in this experiment and 
remains mingled with resulting magnesite. In another experi- 
ment, in which no bicarbonate of soda was added, the portion 
soluble in dilute acetic acid contained 90°3 of carbonate of lime 
and the residue only 68 p. c., the remainder being carbonate of 
magnesia. The result of these experiments, like that of von 
Morlot, is thus chiefly a mixture of carbonate of lime with mag- 
ia, 
In the above asin all the experiments at temperatures over 
100° C., here described, I have made use of bronze tubes hold- 
ing about 14 c.c., with screw-caps made tight by an interposed 
disk of lead, and heated in an oil-bath. 
§ 105. It was next to be seen whether the hydrous double 
