124 Scientific Intelligence. 
When freshly precipitated dianic acid is heated to boiling with dilute 
sulphuric acid, the milky liquid poured into a glass, and grains of dis- 
tilled zine thrown in, the dianic acid in a few moments becomes smalt 
Dianic acid appears to exist, though in a less pure state, in the tanta- 
lite from Greenland, in pyrochlore from the Ilmengebirg, and in the brown 
Wohlerite—though the author had but small quantities of these miner- 
als at his disposal. A small piece of black yttrotantalite, believed to be 
from Ytterby, gave the reaction of dianic acid. A second specimen, how- 
ever, » specific gravity of which was found to be 5°55, contained tanta- 
¢ acid. 
Titanic acid is easily distinguished from the other acids of the same 
group, by boiling it with muriatic acid and tin, and diluting the solution 
with water. The blue color then passes to rose red, and the solution re- 
tains this color several days. When dianic acid is present, the blue color 
predominates, but after standing some hours the rose color of titanic acid 
ars 
appears. 
The tantalite from Tammela, which Von Kobell terms dianite, has 4 
specific gravity of 5°5—while the other tantalites vary in density from 
7:06 to 7:5. The streak of dianite is dark grey, while that of the tanta- 
Pe 
of water at 100°C. ; by J. W. M 7.*—In Berzelius’ Traité de Chimie 
of mercury in considerable quantity at 60° to 80° C. with the vapor 
water, the more volatile substance carrying with it the less volatile, as in 
hen heated. 
1 ve been very generally noticed by the 
compilers of chemical text-books in treating of the history of mercury; 
though it is always stated that the metal is capable of volatilizing 10 4 
very slight extent, even when alone, at the common temperature 0} 
atmosphere. Some doubt toq would seem to have been thrown upon 
Stromeyer’s observation by the experiments made, under peculiar condi- 
* Communicated by the author, 
ee 
