Mineral Point tribune. (Mineral Point, Wis.) 1869-1938, 1877-05-16
MECHANICAL AND SCIENTIFIC.

AT recent meeting of the French
Academy, Nj. de Romilly called atten-
| ton to some remarkable effects OBJ
tanned by suspension of water sucked
up into bell jar closed below by a
tissue with wide meshes. In one
arrangement, the net being metallic,
the suspended water could even be
boiled by heat applied below.
Careful experiments indicate that
dark-colored substances absorb and
emit odors to greater extent than
those which are light-colored
With knowledge of this fact. nurses
should invariably dress in light colors.
y black cotton dress is bad, a black
wool one worse, a black silk worst Of
all. As black is the most absorbent
and most emissiye of odorous and
other eifluvia, physicians should dis
card dress of that color on account of
danger to themselves and PATIENTS
Chicago Journal.
"A curious discovery regarding the
production of heat in metals is de-
scribed by NJ. Oliver in Complies Rem
dtts. a square bar of steel, fifteen
nm. in width and seventy to eighty
ctm. in length, being seized with the
two hands, placed at one end and at
the middle of the bar, while the other
end IS held firmly against an emery
wheel rotating rapidly, a considerable
degree OF heat Is soon generated ut the
rubbed end, and is strongly felt at the
opposite end but not in the middle OF
the bar. This shows that, in certain
cases heat is not communicated in
metals from one part to that next it.
Friction tapers are now made in
England from a mixture of one ounce
saltpeter. one-half ounce powdered
orris root, one-eighth ounce minium,
and one ounce phosphorus; on the lat
ter being dissolved, one to two ounces
of castor-oil are added, the quantity
varying according to the resultant
tenacity of tlexibility required. After
all the ingredients are well incorpo-
rated, chloride of sulphur is added in
the proportion Of from ten to fifteen
parts of liquid chloride of sulphur to
every hundred parts of oil; the whole
is now agitated quickly and shaped
into the form required, either by mold
ing. pressing, cutting or drawing
M. Parone, of Turin, proposes u
very simple method, as compared with
any others now in use, for rendering
textures thoroughly waterproof. The
plan is to dissolve in fourteen pints of
water heated to about 1870 degrees
Fahrenheit, ten and one-half pounds
of gum lac, and shaking the liquid till
the gum lac is completely dissolved.
1t is then removed from the fire, and
to the mixture is added, in small guam
titles at time, twenty-one pounds of
powdered alum, the whole being
shaken till the alum is dissolved. The
liquid thickens, forming an insoluple
| al..mina soap which remains closely
incorporated with the gelatiuc and
| gum lac. 1t is spread over the tex
lures with brush.
The French gutta- percha, for
which so much superiority is claimed
by its manufacturers. is bleached by
dissolying the material in twenty times
its weight of boiling benZole, to which
is added plaster of the best q lality,
the mixture being agitated from time
to time. By reposing for two days,
the plaster is deposited, and carries
down with it all the impurities of the
gutta- percha, insolnble in benzole.
The clear liquid, decanted, is intro
| duced by small portions at time into
twice its volume of alcohol, 90 per
cent, continual agitation being prac-
| ticed. During this operation the
gutta-percha is precipitated in the
state of pasty mass, perfectly white
in its appearance. The desiccation of
the gutta-percha, after it has been
purified, requires Il thorough exposure
to the air, though the process is accel-
Grated by trituration in "A mortar, thus
liberating the moisture which it re-
tains.