16 J, M. Ordway on Nitrates, | 
have here put down the lowest point at which each of the salts. 
tried has actually been observed to remain liquid without any 
special precautions being taken to retard the crystallization. — 
-With some few of the nitrates it makes a difference in this re _ 
| 
nitric acid. In only two cases, has the same base been found — 
capable of forming two different crystallized nitrates. | 
SEXHYDRATES, 
Nitrate of Magnesia, Mg 8 t1,.—This salt melts at 194° F. The — 
liquid has been cooled to 188°. It boils at 290°. . 
Vhen the heating is continued, the salt remains liquid and _ 
clear till about five equivalents of water and a little of the acid — 
are expelled. The residue is not entirely soluble. It becomes — 
hot in recombining with water. x 4 
_ Nitrate of Zinc, tn & 1,,—Melts at 974° F. It has been cooled 
in the liquid form to 87°. It boils at 268°. 3 
Some of the melted erystals, on continued boiling, remained 
thin and clear till 42 p.c. of the weight was gone. The residue 
hardened to a vitreous mass on cooling, which had a composition 
