Scientific Intelligence—Geology. 367 
several parts, makes in a few days so many entire polypi. Curious 
phenomena are produced when a crystal is transferred from one 
solution to another. 2 
4. Natural Deposit of Saltpetre.—Professor W. H. Ellet, of the 
United States, reports that there has been discovered in Bradford 
County, Pennsylvania, a regular vein of nitre, believed to be 
unique in its character. The nitre occurs as a solid and uncrystal- 
line deposit in the horizontal seams of a sandstone rock, and in 
veins proceeding from them at different angles; and the rock itself, 
which is quite porous, is abundantly charged with the same material. 
The nitre itself is very pure, containing more traces of nitrate of 
lime and magnesia. The sandstone in which it occurs is siliceous, 
containing a little carbonate of lime, and a notable quantity of sili- 
cate of potash. (The Dublin Monthly Journal of Industrial Pro- 
gress, No. viii., p. 242.) 
0. Artificial Formation of Minerals by Igneous Action.—Pro- 
fessor Hausmann, of Gottingen, has recently published a memoir on 
the formation of minerals in and about furnaces, by furnace action. 
He enumerates the following varieties observed by him: silver, lead, 
copper, iron, bismuth, lead-glance, blende, oxide of zinc, red copper 
“ore, iron-glance, magnetic iron-ore, crysolite, pyroxene containing 
alumina, Humboldtite, orthoclase, lead-vitriol, and arseniate of nickel 
brown, yellow, green, and black blende were observed formed in the 
furnaces of Lauten Valley, Hartz, in regular octahedrons and dode- 
cahedrons ; also in lamellar and radiated concretions. Lead-glance, 
he says, is often formed by sublimations in the chimneys of furnaces, 
and the crystals are cubical with the usual cleavage ; and crystals of 
magnetic iron sometimes incrust cavities in the stone or brick work 
of the furnaces. 
6. The Use of the Microscope to Mineralogists.—M. Dufour 
has made an important microscopical discovery that will be found 
useful in many circumstances. He has shown that an imponderable 
quantity of a substance can be crystallized, and that the crystals so 
obtained are quite characteristic of the substances. For example, 
he crystallized imponderable quantities of sugar, chloride of sodium, 
of arsenic, and of mercury, and the crystals obtained were quite 
characteristic of these substances. The mineralogist and toxicologist 
may find this process extremely valuable when the substance for 
examination is too small to be submitted to tests.—(L’ Institute, 
No. 1067.) 
GEOLOGY. 
7. Earthquake Indicator—M. Ratio-Menton, a gentleman 
connected with: the French diplomatic corps in the Argentine Re- 
public, has recently communicated to the Paris Academy of Sciences, 
in a letter addressed to the French Minister of Foreign Affairs, a 
