The new dominion. [volume] (Morgantown, W. Va.) 1876-1904, 1878-06-08
Scientific.

One of the most curious recent appli-
cations of photography is its possible
adaptation to the discovery of disease.
Vogel mentions case where the face of
the sitter appeared in the portrait COW
cred with spots, although none were
visible on the skin. On the day follow
ing that on which the picture was taken,
an eruption did appear, and the person
afterward died of varioloid. The feeble
yellow of the incipent pustules had
and the disease had shown itself to the
camera before it had been recognized by
the doctors.
The repeated applications in copper
or brass, of alternate washes of dilute
acetic acid and exposure to the fumes of
ammonia will give very antique look
ing green bronze; but quick mode of
producing similar appearance is often
desirable To this end the articles may
be immersed in a solution of one part
of perchloride of iron in two parts of
water. The tone assumed darkens with
the length of immersion. Or the articles
may be boiled in strong solution of
nitrate of copper. Or, lastly, they may
nitrate of iron, and two ounces hypo-
sulphite of soda in one pint of water.
Washing, drying and furnishing COM
plete the process.
NM. Marcker and Berthold, of Paris,
have lately made some suggestive an
nouncements as to the permeability to
gases and vapors, of various materials
used for building purposes. They claim
as the result of their experimental re.
search that when dry bricks, sandstones
tufa, mortar and cements permit vapors
to pass through them, while granite,
porphyry, slate, alabaster and limestone
are practically quite impermeable. II
will be inferred from these statements
therefore, that the cementing of cellar
| floors, ETC., or laying them with bricks
erably increase the wholesomeness of g
dwelling exposed to dangerous gaseous
exbalations from sewers and the like
does not afford complete protection
Whitewash applied to wall, though il
exerts for considerable time a purify
ing chemical influence, does not aforc
nearly so good protection against {
passage of gases and vapors as a couple
of coats of oil paint, while thick glazec
wall paper reduces the permeability Of
mortar nearly forty per cent
| A pulley over twentyfour inches II
diameter should be built on spider
all under that size can be made on {
wood center-piece about two inches
thick, having a cast-iron fange, say
eight inches in diameter, for a twenty
inch pulley, with hub and boss abou
three inches long. Four bolt hole
should be made through the fange fo
boiling to wood center. The latte
should be a nice fit on the shaft, with
key seat the same as for an iron pulley
After preparing the center-piece by
planning smooth and straight, make
templet, the length being about one
sixth or one-eighth of the diameter ant
two inches wide By this mark out tn,
the amount of stuff for the required
width of face. The lumber should b,
about seven-eighths or one inch thick
sawed out to the same circle as center
piece. Plane straight and smooth, anC
make the butt joints a perfect fit: glu,
and nail on. If fange is desired OF
each edge to keep the bolt from runnin.
off, make the'outside layer little wider
and allow it to lap over the face. Pu
the pulley into lathe and turn it up
Thus made, it will be durable and will
| not easily break