Abstract
An apparatus for in-situ observation and precise measurement of growth rate of crystals from aqueous solutions which can be used in a non-thermostated room is constructed. The apparatus consists of 1) a thermostated vessel to prepare saturated solution with temperature control within ±0.01°C, 2) a growth cell which is used on the microscope stage, and 3) temperature control units. The temperature control units are newly designed by combining the on-off and continuous regulators by which temperature is controlled with an accuracy of ±0.01°C. Even in the growth cell operated in an ordinary room where temperature fluctuates largely, the temperature in the cell could be maintained within ±0.01°C fluctuation for about 30 minutes. Examples to demonstrate the capability of the apparatus are shown for growth rate measurements of NaClO3 and KBr.