ROTHNEY'S SELF-ACTING THERMOSTAT.
Shirley Hibberd
<a class="external free" href="https://en.wikisource.org/wiki/Page:The_Amateur%27s_Greenhouse_and_Conservatory.djvu/38">https://en.wikisource.org/wiki/Page:The_Amateur%27s_Greenhouse_and_Conservatory.djvu/38</a>