Immagini

DESCRIPTION

Exhibit 759 is a Babinet goniometer used in mineralogy and in optics for measuring the angles of crystals; also the dihedral angle between the sides of a prism using the method of the angle of minimum deviation; also the index of refraction of glass as well as spectroscopic measurements. It consists of a graduated horizontal circle rotatable around its axis, supported by a brass column on a tripod with leveling screws.

To measure the dihedral angle of a prism, start by positioning the prism at the center on the rotatable disk supported by the same column. Below the circle there is the support for the collimator. Above the circle there is the support for the telescope positionable with a micrometric screw and legible using the vernier having sensitivity of 30". To effect the measurement shine on one face of the prism a beam of monochromatic light. Now adjust the telescope so that the image of the slit coincides with the reticule in the telescope. Note the position of the telescope and rotate the prism until the second face of the dihedral coincides again with the reticule in the telescope. The angle of the prism is the angle read on the vernier?

ISCRIZIONI

1. Sui raggi è scritto il nome del costrittore: "F. Pellin Paris"

BIBLIOGRAPHY

• [1] URL [ http://it.wikipedia.org/wiki/Jacques_Babinet ]

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