56 Transactions of the American Institute. 



SCIENTIFIC LECTURE-III. 



OlS THE BAEOMETEK. 



By Pkofessob Guyot, op Pkikceton College. 



Judge Chas. P. Dalj presided at the lecture delivered on the eve- 

 ning of December 11, 1868, and, after alluding to the lecturer's 

 eminent scientific attainments, especially as in physical geography, 

 said it afforded him great pleasure to introduce the distinguished 

 gentleman to the audience. 



Professor Guyot said : Our earth is composed of various elements, 

 as they are called — the solid, the liquid, and the gaseous ; three diff- 

 erent states of matter, which have very different functions in the whole 

 system of the globe considered as one individual. On the solid land, 

 as you are aware, are found by far the highest forms of life, whether 

 plants or animals. It is in the solid ground, also, that man produces, 

 developes, civilizes ; and there alone he can find all the elements for 

 his work. In the water, which covers three-fourths of the whole area 

 of the globe, are found organisms which are quite of a lower grade ; and 

 it is therefore in this sense a lower element. Nevertheless, you know 

 how perfectly indispensable it is for the life of the higher. The third, 

 the gaseous, which surrounds both, seems to be equally necessary for 

 both. Both animals and plants, high and low, all need the atmosphere 

 to give them power, and motion, and movement ; and it is fi-om the most 

 impalpable of all the parts of our globe that we derive the motive 

 power. The combustion which takes place within us by respiration 

 gives us animal heat — also necessary for motion. We see, therefore, 

 that this envelope which is outside our globe, is by no means unimport- 

 ant ; though it does not furnish the material elements necessary for 

 our bodies, it furnishes the power for animscting the whole. It is with 

 this atmosphere that we have to do this evening ; it is the grand 

 receptacle of all the physical influences which flow from the outside 

 and the inside of our globe, and which are the conditions or modity 

 to a great extent the life of organized beings. Hence the vast 



