57 o TEE POPULAR SCIENCE MONTHLY 



SCENERY, SOIL AND THE ATMOSPHERE 



By Professor ALBERT PERRY BRIGHAM 



COLGATE UNIVERSITY 



THE atmosphere is commonly considered as a body of gases sur- 

 rounding the globe, but hardly as a part of our sphere. We must, 

 however, look upon it as being of the very substance of our earth, an 

 integral part of the planet as truly as the waters or the solid crust. The 

 geologist and the geographer, indeed, habitually speak of three envelopes 

 of the globe, the atmosphere, the hydrosphere and the lithosphere. 

 A certain assemblage of gases, all of which may be found in the waters 

 and the rocks, remains in a more attenuated condition as the outer part 

 of the earth. The degree of attenuation increases as we go from the 

 surface of the solid part. Whether the atmosphere actually ceases a 

 few hundred miles, or some hundreds of thousands of miles, from the 

 lithosphere is not important to our present purpose, for its effective 

 work is done within a few miles of altitude. 



Looking at the atmosphere as a whole, its calms are exceptional and 

 its movements are the rule. We may find the gentle breeze, the cyclonic 

 wind or the resistless tornado, but always activity. These movements 

 do not tamely confine themselves to horizontal paths, but the gases rise 

 and plunge, pursue broad curves and narrow spirals, and would present, 

 to an eye that could see them from above, a tumult, like the sea in 

 storm. If we add to these mechanical operations the efficient chemical 

 functions of the atmosphere, we shall be ready to agree that it is one of 

 the most powerful agencies that help to mold the form and fashion the 

 quality of the outer parts of our planet. 



We well understand that all organic life is dependent on the atmos- 

 phere for its existence, and that interchange of materials is constant. 

 The forms of the land are nearly as dependent upon this medium as 

 are those of life. Manhattan Island was once a mountainous tract. 

 The first making of the rocks that composed it was conditioned by an 

 atmosphere. The forces that filed it down to its present forms and 

 heights could not have worked without the gaseous envelope. The 

 channels that invite ships to its water line are an indirect product of 

 atmospheric activity. Indeed, the Palisades Ridge, and the submergence 

 of the coast line are the only features of your inorganic environment 

 that have chiefly been due to underground forces. 



The atmosphere is interwoven with all forces operating on or near 

 the surface. Other, or subterranean, energy could produce but a few 

 types of form. We might have great and swelling ridges or domes, or 

 cliffs due to faulting, involving fracture and dislocation, or volcanic 

 cones, streams or sheet outflows. For such initial forms, apart from an 



