ACM - 52301-ST-5 Models: TECHNOCRACY PVT. LTD. Weiber thermograph is usually with a pen that records temperature on a revolving cylinder. The pen is at the end of a lever that is controlled by a bi-metal strip of temperature-sensitive metal which bends as the temperature changes. Our Weiber Thermo hygrographs are used to produce a continuous record of the variation of both the temperature and relative humidity of the atmosphere against time, by drawing colored traces on a chart. Product Overview: