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"Determination of the optical character of a uniaxial crystal with the gypsum plate. Quartz (+)." -Johannsen, 1908

Gypsum Plate

"Determination of the optical character of a uniaxial crystal with the gypsum plate. Quartz (+)." -Johannsen,…

"Determination of the optical character of a uniaxial crystal with the gypsum plate when the center of the cross is beyond the field of the microscope. Quartz (+)." -Johannsen, 1908

Gypsum Plate

"Determination of the optical character of a uniaxial crystal with the gypsum plate when the center…

"Determination of the optical character of a uniaxial crystal with the mica plate. (a) Positive. (b) Negative." -Johannsen, 1908

Mica Plate

"Determination of the optical character of a uniaxial crystal with the mica plate. (a) Positive. (b)…