2 12 THE POPULAR SCIENCE MONTHLY. 



Oil our earth its furnace is the sun, and its boiler the moist lands, the 

 rivers, lakes, and oceans. But it is evident that its mode of operation 

 would not be substantially aflected if the heat were supplied not as in 

 our case from an outside source, but from the original internal heat of 

 the sun or planet itself. So, also, the essential nature of the cyclone 

 would not be altered whatever be the kind of vapor condensed, whether 

 it be of water, of iron, of copper, of gold, or of granite. The above 

 derivation of the power of the cyclone is therefore applicable through- 

 out time and space. 



For the condensation of any vapor whatever would present very 

 much the same phenomena as those with which we are familiar. Let 

 us suppose the earth of such a temperature as to keep iron in nearly 

 the same condition relatively as water is now ; that is, partly vapor 

 floating in the atmosphere, partly fluid gathered in oceans, lakes, and 

 rivers, and partly like solid snow and ice as in the colder seasons and 

 latitudes. Evaporation would go on at the surface of the fluid iron 

 until the atmosphere became nearly saturated. As soon as condensa- 

 tion began an ascending current would be formed. Toward the bot- 

 tom of this current the winds would rush in spirals just as they do 

 now. As the vapor of iron rose and came to the strata of less and less 

 pressure and temperature, it would expand, cool, and condense, and 

 descend in molten showers of liquid metal. Or, if the temperature 

 were low enough, or the summit of the storm high enough, a shower 

 of iron hail, or snow, would be the result. 



Nor need we stay our imagination here. The time was, when our 

 globe had no solid or liquid nucleus, but was wholly gaseous. It was 

 literally an atmosphere^ and nothing else. All the matter of the earth 

 then floated, a vast globular ocean of vapor. The power which kept 

 its particles apart was heat. Before these particles could come to- 

 gether and tlie solid foundations of the world be laid, it was neces- 

 sary that the heat should be got rid of. The means by which this pur- 

 pose was accomplished was mainly the cyclone. Around the limits of 

 the vaporous world radiation into empty space could go on rapidly. 

 Not so in the interior. Conduction of heat even along a bar of iron 

 is a very slow process. It is million-fold slower through gas. Hence, 

 the quickest way of carrying the heat from the interior to the summit 

 of the atmosphere, where it might escape, was, to carry up the matter 

 itself which contained a large amount of heat, either actual or poten- 

 tial. This work was accomplished by the cyclone. 



Let us endeavor to form some conception of the cyclone of primeval 

 times. Let us fancy ourselves in the solar system ere yet it became 

 separated into insulated worlds, and just as condensation is going on. 

 Gases of different specific gravities tend to intermingle even though at 

 first arranged in separate layers above one another. Many of the 

 gases would also be of nearly the same specific gravity. Hence, al- 

 though in general the denser gases would tend together toward the 



