The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1866-04-16
NOTES ON SCIENCE.
MAGNEsIA oRUo1BLEs.

an exceedingly ingenious and capable man, who
is not content with examining merely what is
sent to hlm by the Government, but is himself
constantly engaged upon original researches into
the properties OF the metals and the best methods
for iusing them. We are indebted to him for our
knowledge of several oil the rare metals, and tor
economical ways in which to prepare them.
Captain Caron has recently been investigating
the origin Of the bubbles which form IN cast
steel Just as 1t is setting, and greatly deterlOrates
its value. He has propounded the theory that
the carbon of the steel and the scate of iron,
from the silica of the crucible, react upon each
other to produce the gas which occasions the
bubbles. The sllicate of IRON in state OF fusion,
by contact with the carbon OF the steel, gives
rise to carbonIc oxide gas. In order to prevent
this reaction it win be necessary to make use OF
cruCibles which contain no slllca and which
will endure high heat Saint Clair Deville has
employed crucibles OF magnesia for melting
some of the metals, and 1t Is thought that they
can be made suitable for the fusion OF steel.
Captain Caron advises all meters and refners to
try lime or magnesia crucibles as substitute
for those containing silica. All the difficulties
encountered in the preparation of the crucibles
are not yet overcome, but the question appears
to be approaching its final solution.
ETCHING ON GLASS.
To render glass opaque, the following method
is employed in the establishment of Baccara.
The object to be etched is to be immersed IN the
following magna:-one thousand parts Of water,
two hundred and fifty parts OF well-crystallized
huohydrate OF tluoride OF potassium and two
hundred and tittv parts of chloride of ammo
mum, 10 WnlCn elJnef some eulDnate OF ammo
Lila, oxaate of potassa or chloride Of zinc is to
be added. The etched surface is soon covered
with insoluble Opaque salts, and the transpa
rency of the glass destroyed
This fuoride of potassium is the salt which
DR.. Gibbs proposes to employ in the preparation
of pure oxides of some of the metals, and Its
manufacture in large quantities would be of
great service in the arts
GUIDE TO THE EXPOSITION.
Hachette & Co., of Paris, have published
10 n Universal EXnOaitinn
compiled from official documents, and gives a
foretaste OF what the commissioners propose to
accomplish. 1t may serve to show how near the
realization comes to the grand schemes proposed
by the commissioners.
TUNNEL UNDER THE ENGLISH CHANNEL.
English engineers have recently been in Paris
to obtain the authorization of the French Gov
ernment to have soundings and measurements
made on the French coast with reference to the
construction OF a tunnel from Calais to Dover.
The distance would be at least thirty miles. 1t
appears to be an impossible engineering pro-
blem, but the Mont Gents tunnel Is cited in sup
port of the feasibility OF the scheme.
There are few undertakings the success of
which would be hailed with greater satisfaction
by the travelling public than this. No traveller
to the Continent can ever forget that wretched
English Channel and the miserable little tubs of
steamboats, in which passengers are ferried
across.
ANALYSIS OF MINERAL WATERS.
DR.. Gepmann, of Syracuse, has published
some Investigations upon the subject of the due
allowance to be made for the influence of mix
lures of salts in solution upon the composition
of mineral waters In making up the results of
their analyses, chemists have hitherto been in
the habit of ASSIGNING the strongest acid to the
strongest base, without taking into consideration
the influence of mixtures upon the formation of
salts. DR.. G9pmann has shown:-l. That car
Donate of magnesia, in the presence of sulphate
of lime and tree carbonic acid, will yield sui
phate of magnesia, carbonate of lime and some
basic carbonate OF magnesia 2. That carbonate
Of magnesia sulphate of lime, free carbonic
acid, and chloride of sodium, form chloride of
magnesium, sulphate of soda, and carbonate of
lime. B. That carbonate of magnesia and
chloride of calcium mutually decompose each
other. a. That carbonate of lime and chloride
of magnesium are Indifferent in their behavior
towards each other.
If the views OF DR.. Gnpmann are correct the
analyses of mineral waters will have to be sub
jected to new arrangement founded upon the
influence OF sails in determining chemical de-
composition. This is new and important con-
trbution to the literature of mineral waters.
DR.. Chandler has remarked in long and
very able paper on the same subject, that the
temperature of the water and the pressure of
steam must be taken into account as modifying
the reactions OF the salts. The same subject
has also been ably treated by Mr.. 7. Sterry
Hunt.
HOT SUMMER.
If we examine the tables of mean temperature
for series of years, we shall find thai there is
tolerably uniform rising and descending scale.
III JDe winter De cOlu Jne summer is apt 10 Oe
hot Therefore, look out for warm weather the
coming summer, unless the meteorologsts are
at fault in their calculations.
TO EXTNGUIsH FIRES.
A large fire from petroleum was extnguished
in some vaults in Nantes by pailtul OF solu-
ton of sal ammoniac Chloride of ammonium.
Dilute aqua ammonia will serve as well. As
chloride of ammonium can be had at any time
in the lower part of the city, it could often be
employed to great advantage, and ought not to
be forgotten.
ALLOYS OF MANGANESE.
DIR. Prieger, OF Bonn, has prepared alloys of
manganese and iron and manganese and copper.
An intimate mixture of black oxide of manga
nese, powdered charcoal and iron filings or turn
ings is made in black lead crucible holding
thirty to fifty pounds. covering is made OF
contents of the crucible exposed for several
hours to white heat. On breaking the crucible
the alloy of manganese and iron will be found as
a perfectly homogeneous button. Two equva-
Tents of manganese and one equivalent of iron
give an alloy containing siXty-slX per cent. OF
manganese four of manganese and one of iron
gives about eighty per cent. OF manganese.
Both alloys are harder than the hardest steel;
they are capable OF a high polish, fuse at a red
heat, do not oxidize in the air, and only par.
TALLY in water; their color IS between that OF
steel and silver; they could be used for journal
boxes and bearings of machinery and would be
useful in aifording a method for the introduc
tion of given quantities of manganese to iron
or steel castings.
The so-called crystallized iron now employed
in the manufacture of safes owes its peculiar
properties TO the manganese contained in the
metal. In the preparation OF the iron use is
made of the iranklmite ore OF New Jersey, in
stead of the black oxide OF manganese employed
by DIR. Prieger. The alloy of manganese anC
copper is prepared in similar manner, and i
very hard. The proDerties OF this latter allol