566 SCIENTIFIC RECREATIONS. 



When we speak of " crust" of the earth, we do not simply mean the 

 exterior layer of gravel, clay, or stone. The crust is a thick one, and our 

 crust extends just so far as we can cut into it. The surface of the sea can 

 scarcely be termed a crust, but we must penetrate that ever-moving liquid 

 boundary, and touch upon (and examine) what lies down below far beyond 

 the "full fathom five" of the lead line. In this study we must not forget 

 our Book of Nature, which is always open and inviting us to read. We 

 shall see how things are produced, and how our physical surroundings will 

 continue to be produced until the age of miracles returns, and Providence 

 sees fit to interfere with the otherwise immutable laws which He in His 

 wisdom has laid down for the universe. 



It will be of no use to go back into space and imagine the world a 

 red-hot fragment of matter, whirling through the heaven around the sun 

 which, as a larger aggregation of burning atoms, kept it, as it now keeps it, 

 in its place. The earth was a globe of liquid fire, or in gaseous state, and 

 the atoms gradually cooled on the surface ; the fire is still under our feet. 

 The outer part would by degrees lose all its heat, while the interior remained 

 hot ; the planet must then have been surrounded by a steamy atmosphere, 

 and enveloped in vapours condensed from the air through which no light 

 of the sun could by any appreciable degree penetrate. 



We can give an example of this, and it will be seen how the surface of 

 the earth gradually became formed from the vaporous condition. If any 

 one will take the pains to evaporate any saline solution in a capsule till it 

 is about to crystallise, and observe attentively the pellicle of salt as it forms 

 on the surface ; first a partial film will show itself in a few places, floating 

 about and joining with others, then when nearly the whole surface is coated, 

 it will break up in some places and sink into the liquid beneath, another 

 pellicle will form and join with the remains of the first, and as this thickens 

 it will push up ridges and inequalities of the surface from openings and 

 fissures in which little jets of steam and fluid will escape ; these little ridges 

 are chains of mountains, the little jets of steam those volcanic eruptions 

 which were at that period so frequent, the surface of the capsule is the 

 surface of the earth, and the five minutes which the observer has contem- 

 plated it, a million years. 



The next effect of the cooling of the earth would be the gradual 

 condensation of the vapour of water with which it was surrounded ; this 

 falling upon the earth formed seas and oceans, leaving only the higher 

 portions exposed above its level. The clearing up of the dense dark clouds 

 for the first time let in upon the earth's surface the glorious and vivifying rays 

 of the sun, and this great effect possibly accords with the earliest record in 

 . the Bible of the acts of creation : " And God said, let there be light, and 

 there was light." 



This clearing up of the vapours and the subsequent rain no doubt gave 

 rise to terribly grand electrical phenomena thunderings and lightnings. By 

 degrees the waters got their own way, and then many changes took place, 



