AN APPARATUS FOR THE MICRODETERMINATION OF MELTING POINTS WALTER G. JENNINGS University of California, Davis, California
A NUMBER of microscope hot stages have been proposed for the microdetermination of melting points,'.2 3,4 and several such devices are currently on the market.. A simplified apparatus described here can be constrncted at nominal cost, frequently entirely from scrap material. The apparatus illustrated was constructed from an aluminum block by machining a circular depression in the face and drilling holes as shown. A number 50 drill was used to bore holes in the ends of two 2 6 X 32 machine bolts. These were bolted in position on the Formica block and wrapped with mica tape. A 30-in. piece of 22-gage nichrome wire was wound evenly along the bolts, threaded through the holes, and the bolt. ends crimped. The resistance of this element is 2.5 ohms. I
AMDUR, I.,
AND
A circular coverslip is placed in the center depression and the sample, which can consist of a single crystal, is centered. A second coverslip is placed on top. The stage is heated by applying 6-10 volts through a variable transformer. Melting can be conveniently observed. with a polarizing microscope, or by inserting polaroid discs in the light source and eyepiece of a standard microscope.
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E. V . HJORT,Ind. Eng. Chem., Anal. Ed.,
2, 259 (1930).
CLEYENQER, J. F.,Ind. Eng. Chem., 16,854 (1924). DUNBAR, R. E., Znd. Eng. Chem., Anal. Ed., 11, 516 (1939). ' ZSCEEILE,F. P., AND J. H. WHITE,JR., Ind. Eng. Chem., a
Anal. Ed., 12,436 (1940).
VOLUME 34, NO. 2, FEBRUARY, 1957
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