440 THE GEOSPHERES 



phere. Probably tbe centrosphere would not be greatly affected ; 

 yet even so slight a change in circumstance as an increase of 

 temperature by only 200° would remove the hydrosphere from 

 the earth and greatly modify the atmosphere. 



Let us next consider the effect which would follow the reduc- 

 tion of the temperature of the earth by, say, 400° F., something 

 we should have been unable to do a generation ago, but which 

 we can now do easily by reason of recent experiments and dis- 

 coveries in physics. You will remember that about a score of 

 years ago Cailletet of France and Pictet of Switzerland began 

 to liquefy different gases by the application of pressure at low 

 temperature; many of you know that this line of experimenta- 

 tion was continued by the distinguished chemist and physicist 

 of London, Dewar, Avho liquefied one gas after another until 

 every gaseous substance known to man, including hydrogen, 

 has been reduced to the liquid state ; and I am sure many of 

 3'ou know that an American, Tripler, has recently improved on 

 the work of our European cousins and has learned to liquefy 

 air in large quantities, at low cost, by the skillful application of 

 pressure and artificially reduced temperature. Tripler's work, 

 by the way, is worthy of more than passing note, for his ad- 

 vance has given mankind a new hold on the powers of nature, 

 with a promise of practical applications yielding benefits much 

 greater than were promised by electrical control when inventors 

 first began to utilize electricity for mechanical and other pur- 

 poses ; but this is a digression. Now, liquid air is a little lighter 

 than water and boils or evaporates at about 312° below zero, F. 

 So we know that if the temperature of our planet were to be 

 reduced by 400° the atmosphere would cease to exist as such 

 and would shrink to one eight-hundredth of its present bulk 

 and be converted into a hydrosphere ; we know, too, that long 

 before the reduction was completed the hydrosphere would 

 cease to exist as such and would become a part of the litho- 

 sphere, for the waters of ocean and lake would be congealed 

 (as we know from Tripler's experiments) into a dry powdery 

 mass of crystals, crumbling under blows or pressure just as 

 granite and limestone and other rocks crumble at our present 

 temperature; the waters would, become rock added to the rock 

 which now exists. By this transformation the volume of the 

 lithosphere would be augmented by that of the present oceans, 

 the present sea-level would become sea-bottom, and a lighter sea 

 of liquid air (only a dozen or a score of yards in depth) would 



