356 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1910. 



The atmosphere of the sun alone we may observe in its entirety 

 and in its successive layers. Our self-registering apparatus gives 

 in a few moments its general aspect and principal movements. From 

 this point of view it is better known than our own atmosphere, which 

 we may observe only in its lower portions and over a restricted re- 

 gion even with the aid of the telegraph. 



The network of convection currents and the curious filaments 

 discovered in the upper stratum may be found also upon the earth, 

 and so the study of the sun may bring us to a better knowledge of 

 our own atmosphere. 



