Glossary
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analyzer
A second polarizing element inserted above a preparation. When its vibration direction is at right angles to the vibration direction of the polarizer, the field becomes black if no anisotropic specimen is on the stage.
anisotropic
A transparent particle having different refractive indices depending on the vibration direction of light.
anomolous dispersion
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aperture
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Aroclor
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beater
A device that separates the fibers of organic plant matter to make a solution with water.
Becke line
The bright halo near the boundary of a transparent particle that moves with respect to that boundardy as the microscope is focused through the best focus.
birefringence
The numerical difference in refractive indices for a substance. On a given crystal view, the interference color (retardation) between crossed polars depends on the birefringence and thickness:
Retardation (nm) = 100 x thickness (um) x birefringence
blueprint
A type of print used for copying engineering drawings and similar
material. The name is popularly applied to two separate methods, more
exactly designated as the blueprint and the whiteprint, or diazotype.
In blueprinting, the older method, the drawing to be copied, made on
translucent tracing cloth or paper, is placed in contact with paper
sensitized with a mixture of ferric ammonium citrate and potassium
ferricyanide, which is then exposed to light. In the areas of the
sensitized paper not obscured by the lines of the drawing, the light
reduces the ferric salt to the ferrous state, in which it reacts with
the potassium ferricyanide to form insoluble prussian blue. The exposed
paper is then washed in water, producing a negative in which the lines
of the drawing appear in white against a dark blue background.
Cargill meltmount 1.666
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cationic substance
Substance containing positively charged ions.
cellulose
Main part of the cell wall of a plant.
cohesion
What occurs when like substances stick together without any cementing surface.
color
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compensating filter
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conchoidal
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condenser
The lens system mounted under the stage of the microscope to furnish a cone of light to the specimen. There are two basic types of condensers: brightfield and darkfield.
condenser diaphragm
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cores
Contains the protons, neutrons, and inner electrons of an atom.
couching
The method used by hand-papermakers for transferring wet pulp from a deckle and mold to a pelon for continued drying.
cross-hairs
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crossed polars
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crystalline
A substance (usually solid but can be liquid) in which the atoms or molecules are arranged in a definate pattern that is repeated regularly in three dimensions. Crystals tend to develop forms bounded by definitely oriented plane surfaces that are harmonious with their internal structure. They may belong to any of six crystal systems: cubic, hexagonal, tetragonal, orthorhombic, monoclinic, or triclinic.
cubic
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deckle
A frame apparatus used in conjunction with a wire mesh mold to form an edge on the drying paper.
destructive interference
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dispersion
The variation of refractive index with color (or wavelength) of light. The spreading of white light into its component colors when passing through a glass prism is due to dispersion which, in turn, is due to the fact that the refractive index of transparent substances is lower for long wavelengths than for short wavelengths.
durability
The resistance to normal wear and tear.
dyes
A soluble or insoluble coloring matter.
extinction
If the orientation of the crystals that appear white or colored between crossed polars is changed by rotating the stage, all single crystals will be observed to disappear (become black) four times during complete rotation of the stagee. The positions are 90o apart; they reveal the vibration directions of each crystal. These directions will parallel the vibration directions of the two polars when the crystal is extinct.
fibrils
Small hairlike abrasions on the surface of every fiber.
floating deckle
A shaping device that gives form to the paper during the drainage process.
focal plane
A plane that is perpendicular to the axis of a lens or mirror and passes through the focus.
Hollander beater
A device that separates the fibers of organic plant matter to make a solution with water.
homogeneity
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hydration
When pulp chemically combines with water.
isotropic
Substances showing a single refractive index at a given temperature and wavelength no matter what the direction of light through the particle. They show no interference colors between crossed polars. Examples are unstrained glasses, unoriented polymers and compounds in the cubic system.
lamp iris
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malachite
mordant
A chemical that fixse a dye in or on a substance by combining with the dye to form an insoluble compound.
mounting media
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objective
A lens or system of lenses that forms an image of an object.
oblique extinction
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octaves
The principle that for every eighth element certain properties repeat.
ocular
permanence
The resistance to effects of time by internal or external factors.
pinhole camera
A (usually homemade) camera which uses the method of exposure to light through a
pinhole to form an image upon film. The image is formed when light enters the
pinhole, and is projected upside-down onto the negative.
plane polarized light
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polarization colors
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polarizer
A polarizing element which is placed below the preparation with its vibration direction preferably set in an E-W direction.
polycrystalline
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precipitated
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printmaking
An art form consisting of the production of images, usually on paper but
occasionally on fabric, parchment, plastic, or other support, by various
techniques of multiplication, under the direct supervision of or by the
hand of the artist. Such fine prints, as they are known collectively,
are considered original works of art, even though they can exist in
multiples.
refraction
The change of direction and/or velocity of light as it passes from one medium to another.
refractive indices
The ratio of the velocity of light in a vacuum to the velocity in some medium. Refractive indices generally increase with the atomic number of the constituent atoms. A high density or high atomic number elements usually results in high refractive indices.
retardation
The actual distance of one of the doubly refracted rays behind the other as they emerge from an anisotropic particle. It depends on the different in the two refractive indices, n2 - n1, and the thickness.
shape
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silver halides
A milky substance of microscopic crystlline particles, sensitive to blue and ultraviolet light. When specific dyes are added to the mixture it becomes sensitive to other colors of light. Silver-halide substance is commonly referred to as emulsion.
tearing resistance
High resistance against tearing in paper of long fibered pulp.
Tetrahedron
A four-sided, three dimensional figure used to model a molecule that contains four electron pairs.
transparency
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triads
Groups of three elements exhibiting similar properties.
vermilion
Mercuric sulfide; a brilliant red pigment used most frequently in paintings dating from the Renaissance period.
vibrational path
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