A clamping screw can lock the axis of the graduated circle and the crystal holder for either independent or simultaneous rotation.
These instruments include a horizontal graduated circle with a centering and adjusting crystal holder suspended below instead of being positioned above (Fig.
This three-circle goniometer--the largest ever constructed--likewise had a suspended crystal holder and was suitable for Kohlrausch studies.
The complexly constructed crystal holder replaced the small button that usually rests on top of the goniometer head and permitted unlimited manipulations of the crystal.
It consisted of two parts: the simple C-shaped crystal holder was connected directly onto the top of the goniometer head.
Flower holder by Skinmarket, Swarovski pink crystal holder
by Alex & Ani, sequin holders by Claire's
Its most important innovations were that (1) the crystal holder
was mounted on a circular plate with degree markings so that the horizontal direction and vectoral difference in hardness was measurable; (2) the base of the crystal holder
was no longer moved by hand but by a screw mechanism, allowing uniform movement under the scratch point; (3) the various weights were placed on a small pan directly over the scratch point; and (4) the height of the balance beam was adjustable by means of a screw mechanism, and an eccentric disc served to restrain the beam when in an unweighted condition.
By means of an adjustment mechanism (shown in the drawing on the right), and with the help of a guide rail for the crystal holder, the crystal edge to be measured can be oriented exactly horizontal and parallel to the axis of the semicircle.
In the center of the circle, two nested cylindrical axes are found, one joined firmly with the crystal holder, the other with an indicator with a vernier mounted at its end.
The goniometer has a vertical graduated circle, a fine adjustment and vernier read-out, and an adjustment device for the crystal holder.
A stirrup-shaped crystal holder is attached to one end of the rod, and on the other is a radial indicator with a vernier [ILLUSTRATION FOR FIGURE 25 OMITTED].
The guests' tables were decorated with pink flower arrangements, tea-light candles in crystal holders
, and at each seat was a black or white cloth napkin monogrammed with an embroidered "D" on it.