Pantelegraphy.
A system of telegraphy for transmitting designs, maps, drawing, and the
like by telegraphy. (See Telegraphy, Facsimile.)
Paper Filaments.
Filaments of carbon for incandescent lamps made from paper.
This is one of the earliest materials practically used. The paper is cut
out of proper shape, and is carbonized in a close vessel, while embedded
in powdered charcoal or some other form of carbon to absolutely cut off
access of air. It is then placed in the lamp chamber and flashed or
subjected to the regular treatment.
Parabola.
A curve; one of the conic sections. It is approximately represented by a
small arc of a circle, but if extended becomes rapidly deeper than a
half circle.
If, from a point within called the focus, lines are drawn to the curve
and then other lines are drawn from these points parallel to the axis,
the angles of incidence will he equal to the angles of reflection as
referred to tangents at the points where the lines touch the curve.
[Transcriber's note; The general equation of a parabola is
A*x^2 + B*x*y + C*y^2 + D*x + E*y + F = 0
such that B^2 = 4*A*C, all of the coefficients are real, and A and C are
not zero. A parabola positioned at the origin and symmetrical on the y
axis is simplified to y = a*x^2 ]
Parabolic Reflector.
A reflector for a light, a paraboloid or surface of revolution whose
section is a parabola. A light placed at its focus has its rays
reflected parallel to each other.
Examples of parabolic reflectors are seen in electric search lights and
in locomotive head-lights. They are employed in electric search lights.
The arc light must be of such construction as to maintain its ignited
points always at the same point, the focus of the paraboloid.
Paraffine. v.
To coat or saturate with paraffine wax. Paper may be paraffined by
dipping in the wax, or by being sprinkled with fragments of wax,
subsequently melted in with a hot iron or otherwise. The tops of battery
carbons are often paraffined to prevent the acid from rising in the
pores by capillary attraction and rusting the connections.