On show in London during the Physical Society's annual exhibition at the Imperial College of Science & Technology last month was a delicate device of highly specialized application. Essentially it consists of two thermometers hooked into an electric circuit. In practice one thermometer is buried just under the surface of the soil, the other supported in the air just above. The upper thermometer gives the air temperature, and since the buried one cannot be seen, a dial records the temperature differential between the two. From that the warmth of the ground can be...
To continue reading:
or
Log-In
