{819.] Scientific Inéelligence. 229 
describes in this paper, I am tempted to suspect that the chloride 
a iron is the substance possessed of this desirable property. 
robably successful results might be obtained by adding chloride 
of iron to glass already in fusion. It would be an object worth 
the while of our Staffordshire potters to try the properties of 
chloride of iron and some other metallic chlorides as paints, either 
mixed with glass in the proportions that suited best, or perhaps 
mixed with their common enamels. ‘There is every reason to 
expect that these chlorides would communicate colours different 
from the oxides of the same metals. If colours could be made 
from them for the use of the painters by uniting them with silica, 
as is the case with ultramarine, such colours would be much 
more valuable than those at present in use; because they would 
not be liable to undergo alterations from the action of the atmo- 
sphere, or the light of the sun. Our painters at present make 
use of colours possessed of so little permanency that the picture 
is scarcely calculated to outlive the artist. 
VIII. Fusion of Platinum. 
It is said that M. Prechtel, Director of the Polytechnical In- 
stitute at Vienna, has succeeded in fusing platinum by means of 
a very violent heat in very refractory crucibles. The greatest 
degree of heat which he has produced may be estimated at 180° 
Wedgewood. When platinum is thus fused, its specific gravity 
is reduced to 172. It may be scratched by aknife. It may be 
readily beat out under the blows of the hammer, and may be 
easily divided by the saw, like copper. When heated to redness 
and struck with a hammer, it scales off, and exhibits a granular 
fracture, similar to that of cast-iron. This Jeads to the opinion 
that the platinum crystallizes during its solidification. Crude 
platinum does not fuse at so low a heat as pure platinum.—(Gil- 
bert’s Annalen, Jan. 1818.) 
IX. Formation of the Vegetable Epidermis. 
Grew and Malpighi were of opinion that the epidermis of 
plants is merely a scurf formed upon the parenchyma of the bark 
by the action of the air. Mirbel has lately supported the same 
doctrine, and endeavoured to obviate the objections that natu- 
rally rise in one’s mind when such an opinion is advanced. But 
Mr. Keith has shown that some of the most formidable objec- 
tions of all have not been noticed by him. If the vegetable 
epidermis were merely the result of the action of the air upon 
the “beet te it would follow that the epidermis would never 
be formed till the part were actually exposed to the action of 
the air. But this is not the case. If we strip a rose bud, or any 
other flower bud of its covering, we shall find that every petal is 
covered with just as perfect an epidermis as those parts of the 
plant which have been exposed to the air. When the epidermis 
of the leaves or petals is rubbed off, it is never renewed. When 
the epidermis of the stems of woody plants is rubbed off, it is 
