Army worm is a name sometimes given to the grubs of a small black fly, very common in some European forests. In the United States the name is given to a voracious moth, common everywhere, which collects in large numbers.

One pair of rabbits can become multiplied in four years into one million two hundred and fifty thousand. They were introduced in Australia a few years ago, and now that colony ships six million rabbit skins yearly to England.

The nautical term "trade winds" applies to constant winds which blow at sea to the distance of about 30° on both sides of the equator. On the north of the equator they blow from the north-east, and on the south from the south-east.

Lead in the form of filings, under a pressure of two thousand atmospheres, or thirteen tons to the square inch, becomes compressed into a solid block, in which it is impossible to detect the slightest vestige of the original grain. Under a pressure of five thousand atmospheres it liquefies.

Below half a mile in depth the water of the ocean is intensely cold, remaining both winter and summer at a point only slightly above freezing. The contents of a trawl hauled up from the floor of the sea at the equator, will be found to include mud and ooze that is nearly freezing.

Simoom (Arab, samum, fr. samma, he poisoned) is the designation of a hot, dry wind, laden with dust and sand, which prevails in Africa and Arabia, especially at the time of the equinoxes. It originates in the sand deserts of the interior. Called Sirocco in South Italy, and Solano in Spain.

Richard Proctor, the astronomer, said that when a novelist attempts to describe a scientific phenomenon, he should take care to be exact, for people pay more attention to the descriptions of the novel than to those of the scientific text-book.

We have sixty divisions on the dials of our clocks and watches, because the old Greek astronomer, Hipparchus, who lived in the second century before Christ, used the Babylonian system of dividing time, and that system being sexagesimal.

Tin, when compressed in powder, becomes solid under a pressure of ten tons on the square inch, zinc at thirty-eight tons, antimony at thirty-eight tons, aluminum at thirty-eight tons, bismuth at thirty-eight tons, and copper at thirty-three tons.

The volume of a portion of gas varies inversely as the pressure. Thus if we double the pressure, the gas will be reduced one-half; if we treble the pressure, the volume of gas will be reduced to one-third, and so on. This is the fact which physicists term Boyle's Law.

It is believed that whales often attain the age of four hundred years. The number of years these huge creatures have lived is ascertained by counting the layers of laminae forming the horny substance known as "whalebone." These laminae increase yearly, just as the "growths" do on a tree.

Scientists say that if the bed of the Pacific ocean could be seen it would disclose to view several mountains with truncated tops scattered over it. These mountains would be perfectly bare at their bases, and all around their tops they would be covered with a beautiful growth of coral polypi.

A camel has twice the carrying power of an ox; with an ordinary load of four hundred pounds he can travel twelve to fourteen days without water, going forty miles a day. Camels are fit to work at five years old, but their strength begins to decline at twenty-five, although they live usually till forty.

Should the earth collide with another world of equal bulk, it is claimed the heat generated would be sufficient to melt, boil and completely evaporize a mass of ice seven hundred times the bulk of both the colliding worlds - in other words, an ice planet one hundred and fifty thousand miles in diameter.

Scientists use the term Choke-damp (also called after-damp or foul damp), to describe the carbonic acid gas given off by coal which accumulates in coal mines, and may suffocate those exposed to it. It is distinguished from fire-damp, the marsh gas or light carburetted hydrogen which causes the explosions.

Our atmosphere which is a gaseous compound of oxygen and nitrogen surrounding the earth, is estimated to extend for a distance of forty-five miles from the globe. It exerts a pressure of fifteen pounds to the square inch on the surface of human and other bodies, but as the pressure is balanced inside and out no inconvenience is felt.

Heredity is the term applied to the transmission to the offspring of the characteristics, mental and physical, of the parent. Such peculiarities may be imparted by the mother or by the father. The study of heredity has in recent years been much developed by Haeckel, Herbert Spencer, Huxley, Darwin, Wallace, Galton, and others When starch is carefully heated to 392° (200° C), or until vapors arise from it, it becomes soluble in cold and hot water, and loses its gelatinous character; it also has the property, when viewed by polarized light, of turning the plane of polarization to the right; hence its name of dextrine. It is often used as a substitute for gum arabic.

According to geological computation, the minimum age of the earth since the formation of the primitive soils is 21,000,000 years - 6,700,000 years for the primordial formations, 6,400,000 years for the primary age, 2,300,000 years for the secondary age, and 460,000 years for the tertiary age, and 100,000 since the appearance of man upon the globe.

Cosmos is a term used to denote the order and harmony of the universe. Originally used by Homer to denote " order " it was applied by Heraclitus and Anaxagoras to the divine order and arrangement of nature; by Plato to celestial and terrestrial order. It was further applied to the habitable world and the world generally as an orderly system.

In geography the basin of a river is the whole tract of country drained by that river. The line or boundary which separates one river-basin from another is called the watershed. By tracing these watersheds, the whole of a country or continent may be divided into a number of distinct basins; the basin of a lake or sea being made up of the basins of all the rivers that flow into it.