A bimetallic strip is not used in a rotary thermometer. Instead, liquid-in-glass thermometers utilize the expansion and contraction of a liquid, typically mercury or alcohol, to indicate temperature.

Here's why a bimetallic strip wouldn't work in a rotary thermometer:

* Rotary thermometers rely on liquid expansion: The core principle of a rotary thermometer is that a liquid's volume changes with temperature. This change is then translated into a rotation of a pointer.

* Bimetallic strips rely on differential expansion: A bimetallic strip consists of two different metals with different coefficients of thermal expansion. When heated, one metal expands more than the other, causing the strip to bend. This bending motion is typically used in thermostats or other mechanical devices, not rotary thermometers.

In short: Rotary thermometers use liquid expansion, while bimetallic strips use differential expansion. They are two distinct mechanisms for measuring temperature and aren't interchangeable in these types of thermometers.