It forms an excellent application of one of the most valuable lessons of physical science in the matter of the conservation of heat.

The Mantis has outstripped humanity in her knowledge of thermic nonconductors or insulators.
The famous physicist Rumford was responsible for a very pretty experiment designed to demonstrate the low conductivity of air where heat other than radiant heat is concerned.

The famous scientist surrounded a frozen cheese by a mass of foam consisting of well-beaten eggs.

The whole was exposed to the heat of an oven.

In a few minutes a light omelette was obtained, piping hot, but the cheese in the centre was as cold as at the outset.