The herald and mail. [volume] (Columbia, Tenn.) 1873-188?, 1874-10-23


no increase of heat second, that loss
OF heat always follows addition of wa
ter third, both the amount of heat and
the temperature of the fire are consid-
erbly diminished.
DETECTION OF STARCH IN MILK.-Dr,
Hagar accounts for occasional discrep-
ancles IN the statements of different
chemists in regard to the presence OF
starch In a sample of milk. by the pc
culiar property which lacteo-protein
substances possess of combining rap
idly with iodine, and thus decolOrizing
q solution of it. In consequence, no re,
action for starch is Obtainable until the
milk is saturated, in this respect, with
the iodine, and by accident q chemist
may stop short of this point, and fail to
get the reaction for starch.
SOLUBLE SEsQUIoxIDE OF IRON IN
DTENG SmK.-The injurious effect OF
the usually very acid mordants upon
the durability OF silk may be avoided
by employing the aqueous solution of
peroxide of iron, which remains in q
dialyser, supplied with bottom of an
imal membrane or parchment paper,
and filled with solution of chloride
of iron, and hoated for some time in a
vessel of water, the large part of the
hydrochloric acid passing into the wa
ter. This solution is also much more
effective than the usual iron mordsnt,
since the affinity of the iron for silk is
not weakened by an acid. In fact NOR
danting by iron salts seems itself to rest
upon dialytic process.
DIRECT PHoTOGRAPHY OF THE SOLAR
Performances Prof. Setback. of Cor
dOba, who has the use of a thirteen inch
Photographic objective, narrates his ex-
perlence IL attending the photography
OF solar protuberances by means of the
spectral line 81. gamma. According to
him, thin aver OF iodide of silver
upon plate of glass absorbs all the
violet light OF the spectrum, aud he
therefore proposes TO cover the surface
OF his lens with thin layer of the sub
stance. By means of the light that is
transmitted he would directly photo
graph the solar protuberances. His
first attempts, for many reasons have
been quite unsatisfactory but the su0.
gestion seems worthy of further develop
ment by those spectroscopists who have
greater conVeniences at their command
REGENERATION OF OIL PAINTINGS
Besides the irremediable darkening of
oil painting by age, they are also liable
to deterioration by the cracking of the
paint on severe drying, and also to loss
OF brilliancy by the formation of num-
berless small assures in the originally
transparent, heavy film of varnish upon
them. The former defect can only be
removed by the tedious filling of the
cracks with fresh paint. As a means for
remedying the latter, DIR. WeiQelt sug-
gests, as an improvement on a plan pro-
posed by Pettenkofer, that the varnish
be partially dissolved, and the assures
thus filled uD, by leading upon the pic
ture, through n gum tube, a blast of air
saturated with alcohol, by blowing it,
by means of a bellows, through a flask
contairg alcohol, and gently warmed.
EXPLOSIONS OF FTRE-DAHrP IN CoA1
MINES The subj ct of the connection
between explosions in coal mines and
the weather has attracted the attention
OF Messrs. Scott and Galloway in Eng
land during the past four years. Their
third report has recently been present
ed, covering the year 1873, from which
1T appears that the number of fatal ex-
pIoslons was ~, causing the loss of 163
lives. Of these explosions So per cent
are due to changes of barometric pres-
sure; II per cent. to great heat Oh
per cent. are not attributed 10 meteoro-
logical agencies. The number of ex-
ploslons is not found to have any appar-
ent dependence upon the direction from
which the wind blows. The results
place 1t beyond the possibility of a
doubt that the escape of fire-damp and
the consequent explosions are related
mainly to the conditions of the atmos-
pheric pressure, and that a careful watch
over the barometer is, above all. neces-
sary to each cOlliery.
The EVAPORATION OF L1oUrDs-Ste-
fan has endeavored to reduce to some
definite laws the phenomena of tbe
evaporation of liquids (especisIIy the
diffusion of vapOrs) and has made n
series of experiments principally on the
evaporation of ether. He finds that in
narrow open tubes the velocity of the
evaporation IS inversely proportional to
the distance of the surface of the H.
quld from the open end of the tube. It
is independent of the diameter of the
tube, and increases with the tempera-
ture, so far as the vapor pressure in
creases with the temperature. IF the
pressure of the vapor becomes eoual IN
that of the air, the formula given nv
Stefan shows that the liquid then boils
II the evaporation takes place in closed
tubes, bubbles 70 m and issue confirm
ally, at such rate that the times in
which equal numbers Of bubbles form
are proportional to the numbers 8. s. Z
etc. If the tube contains HYDROGEN
instead OF air, the bubbles form in one
fourth OF the time /; or, in other words.
evaporation proceeds four times as ran
idly In hydrogen as in air.
FIG CoFFEE.-A coffee substitute of
roasted figs has been in the market i,
Austria for ten years, and ia also me-
pared at present in Berlin. Recent
careful tests of it indicates that II nos
sesses more agreeable flavor than the
chlccory-substitute, and has Tins for
been brought into the market free from,
injurious authorizations, often present in
chlccory-coifee. Samples from Berlin
IN the form OF a coarse brown powder
including yellowish particles, formed
an adherng, slightly gummy mass on
Delng nightly pressed, a sweetish bitter
taste like caramel, and a CORRESPONDENCE
odor. Austrian samples. altbouob in
the main similar to the preceding were
slightly more pulverulent and of q
sourish taste, which fact, together with
the chemical analysis, rendered it prob
able that cheaper, inferior. peTbaps
even spoiled figs, had been used In rs
preparation. At the first Introduction
wonderful medicinal properties were
claimed for it in Austria, especially in
affections of the lungs, etc, and it was
recommended for nervous persons. AL
though it may be serviceabIe in sncb
cases, 1t can hardly be considered me
dlclnal, and the Berlin manufacturer
CHAINS that 1t is more wholesome than
pure cohee, simply because it is less
stimulating. In all cases n ia rooon,
mended to employ an equal quantity of
conee with the substitute, and the color
OF the product is said to be exceedinpIv
tine, as we'll as the flavor. e''
Exquisite Toilets.
Lucy Il. Hooper, in her Paris letter
to the Philadelphia Press, thus de-
scribes the dresses worn bv RIancba