A Microchamber for Low Temperatures ZAEOJ HARVALIK, St. Ambmse College, Davenport, Iowa
I
N ANALYTICAL and preparative chemical work it is often necessary to use fractional crystallization by low temperatures and to determine the physical constants of the crystals frozen out. The microchamher described (Figures 1and 2) makes i t possible to observe through the microscope any' object under the influence of low temperatures in the range of +SOo to -180" C. It can he attached to every type of microscope and can be used for any chemical and biological work where low temperatures are required (f, 8, 3, 6, Y,9,13,14, I R ) .
The microchamber shown in Figure 3 is used on a microscope with illumination from above. The chamber shown in Figure 4 is for microscopes with illumination from below. To attach the microchamher to this type of microscope, the condenser and the mirror must be taken off. The Zumination of the sample in the chamber is provided by a Luoite rod of givenshape (f5).
Description of Microchamber The microchamher is based upon the fact that objects in rooms surrounded by walls at constant temperature get the same temperature as the walls. A constant temperature is maintained by circulating liquids around them. A copper rod shaped as in Figure 3,10, is surrounded by a metal tube, 20, which has two openings. 21. 22. in its side w d s for the ~
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enables better circulation of the' rnrl
iO1. The copper ring insulatks the sample against t & & a i i ~ ~ fluences from above and maintains a constant temperature in the chamber ( 1 2 ) . The chamber and its accessories are protected by a metal np Bakelite covering to avoid thermal losses. This covering, 31, is attached to a metal tube, 30; by cork insulation, 24. Tube 30 itself serves as a means of attaching the whole chamber to the microscope stage by a bayonette lock to a plate, 32, which is screwed, 33, on the miokoscope stage, 40. The space between the sample and the objective should be
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50,da:
,---the overEo
