Corrugated Iron.
We have already seen that the Wasps are paper-makers. We may now see how some of the Wasps have anticipated a valuable invention of man, namely, the principle of corrugation, whereby a thin plate gains strength.
Even a sheet of paper gains great strength by corrugation, as is seen in those paper covers which are so much in use for the decoration, or rather the concealment, of flower-pots. But the best example that can be given of this principle is the Corrugated Iron, which has come so much into use for temporary buildings, such as schools, places of worship, reading-rooms, &c. It is very light and very strong, and can be used either for roof or walls with equal success.
By means of certain wasps belonging to the genus Polistes, Nature produces corrugated dwellings, which are made of very thin materials, but which are marvellously strong in proportion to their weight.
The insects belonging to this genus are all exotic, but are spread over a very large surface of the earth.
So strong are the nests made by some of these species, that they need no external covering, the corrugated paper supplying at the same time strength and warmth, the latter element being furnished by the air which is entangled between the corrugations.
There are many species of Polistes, mostly belonging to Australasia and tropical America, the latter displaying the greatest variety of form and structure in the nest.
USEFUL ARTS.
CHAPTER XV.
Electricity, Magnetism, and Galvanism mutually convertible.—The Force co-extensive with Nature.—Uses of Thunder-storms.—Languor from Want of Electricity.—Frictional and Voltaic Electricity.—Origin of the Name.—Structure of the Voltaic Pile.—A simple Example of the Pile.—Nerves of a Frog’s Leg.—The Electric Shock, and how to produce it.—The Electric Jar and Battery.—Animal Electricity.—The Torpedo and Electric Eel.—Structure of the Electric Apparatus.—The Electric Spark obtained from both Fishes.—Channels of Electricity in the Body.—The Will and the Muscles.—Electricity the conducting Agent.—The Human Body permeated by Nerves.—Telegraph Wires and the Nervous System.—Lightning and the Electric Spark.—The Electric Light and its Power.—The Fire-fly, the Glow-worm, and the luminous Inhabitants of the Sea.—Magnetism and Diamagnetism.—The Electric Telegraph and the Compass.—The Principle identical in both Instruments.