The daily exchange. [volume] (Baltimore, Md.) 1858-1861, 1858-04-09
SCIENCE AND ART

VALUABLE FRENcH DIsCOvERY.-Mr Kuhlmann of
Paris, is the discoverer of process for the forma-
ton of chlorated silver by the humid Way and
which has received the favorable attention of the
French Academy of Sciences. He fills bottle or
globe with solution of nitrate of silver and closes
the orlice with some porous body; the bottle is then
reversed and the oritice plunged in bath of chic
rohydrlc acid-taking care that no air penetrates
into the bottle containing the solution of nitrate of
sllverln such manner that the porous stopping NAV
have one side in contact with the solution of nitrate
OF silver, and the other in contact with the chlorohy
drlc acid After short time the two fluids meet; and
then there is found the top of the stopping inside
the bottle, thin layer of chloride precipita
ted. Thereacon continued slowly, and gives rise to
authorization of chloride of silver The chloride
is first white, and afterwards becomes of brown
sh violet hue, and sem-transparent. The fracture
is conchOida and vitreous; it is of soft consistency
and fusible ordinarily found chlorated silver
NJ. kuhlmann has Inferred from this discovery that
as native chloride of silver is often found with me-
alic silver, the formation of this metal results from
the reduction of portion of the chloride for it has
long been well known with what facility chloride of
silver gives up its chlorine hydrogen as the latter
is evolved.
sophical Magazine contains an interesting paper on
the beautiful art of painting in enamel, in which
the writer says that the ancient ruby glass, on
being exposed to the heat of glass kiln, preserves
its color unmpaired, while the modern suffers con-
siderable injury, and in some cases becomes almost
black. Hence the latter cannot be painted upon as
the heat required to fix the fresh color would de
stroy the beauty of the original basis. To obviate
this difficulty, the artist paints upon a piece of
plain glass the tnts and shadows neces-
sary for blending the rich ruby glow
with the other parts of the picture leaving
those parts untouched where it is desired that the
ruby should appear in undiminished brilliancy, the
ruby-glass being fixed in the picture behind the
painted piece. Colored transparent glass is appied
enamel in silver and gold biouterie, previously
bright cut IN the metal with the graver. The cuts
rejecting the rays of light from their numerous sur
races exhibit through the glass richly stained with
goid sver "copper" cobalt, &C., gorgeous display of
prlsmauc colors, varied with every change of as
pect The artist in enamel has obtained from mod
ern chemistry, preparations of the metals platinum.
uranium, and chromium, which furnish four of the
richest and most useful coors of his palette beinga
most valuable addition to the materials employed in
this art.
New SAFETY PIPE FOR STEAM BoHERs.-A new
and improved mode of applying the fusi6le plug to
steam boilers is proposed to secure the greater
certainty of its action and to remove one of the
principal causes of boiler exposons-that arising
from shortness of water. The principle upon which
the Improvement is based is that II the plug or
plugs are inserted in a small fue or pipe through
which current of the hottest gases taken immedi-
atelv from near the fire Is made to pass, such
nue or pipe being at@the same time at high
er level than the boiler surface over the fire
the fusible plugs will be melted out with great
er certainty, whilst at the same time the boil
ers, not being oyerheated will be uninjured. An
elbow pipe, four inches in diameter, is fitted to the
bottom of the boiler or to the top internal ue of
a boiler, and is made the means of carrying the
heated gases from the furnace to the side or exit
tue, the upper part of the elbow pipe being per-
torated with concal holes, five-eights of an inch
diameter, and filled with fusible metal plugs sim
ply driven in. BY this arrangement, should the
water fall below the upper surface of the pipe the
fusibe plugs, being constantly exposed to the cur
rent of the heated gases passing through it, i'm
medately melt and thus preserve the boiler from
injury.