MILLER— SPROUL OBSERVATORY ECLIPSE EXPEDITION. 279 



streamers and they all possess this property. This may be inter- 

 preted to mean that this mechanical theory of the corona is wrong 

 or that there are other forces acting on these particles than the at- 

 tractive forces of the sun, and of a repulsive pressure that varies 

 inversely as the square of the distance from the sun's center. It is 

 easy to conceive of many forces such as resistance to motion by 

 gases or that the particles at greatest extension of the streamer were 

 lighter than those forming the part of the streamer measured. 



We attempted also to apply Bigelow's earlier theory to the for- 

 mation of these streamers. Miss Smedley was able to show that if 

 this (Bigelow) theory is true that these magnetic forces alone could 

 produce no streamer of the form described in Figure 4 ; that is, that 

 the vectorial angle of the radius vector from the center of the sun 

 to any point P on the streamer either constantly decreases or con- 

 stantly increases as P is moved along the streamer away from the 

 sun. 



Another phenomena which seems very exceptional in the case 

 of this eclipse occurs in connection with the polar rays. In almost 

 no case are the polar rays arranged exactly symmetrical with regard 

 to the axis of rotation of the sun. But in most coronas the vectorial 

 angle of a point p decreases as it moves out along a streamer on the 

 west side of the axis of rotation ; while for those on the east side the 

 vectorial angles increase ; that is, these rays are gently curved away 

 from the axis, but. as I have said, not exactly in a symmetrical way. 

 All these things can be produced under the assumption of the me- 

 chanical theory ; but in this eclipse the vectorial angle decreases as P 

 moves out along the streamer whether it is on the east or on the 

 west side of the axis of rotation, and this is true not only of the 

 rays around the north, but also around the south poles. I have not 

 had time to investigate whether or not this is possible under the 

 mechanical theory. 



It seems probable to me that the long graceful streamers of the 

 corona, at least the part of them that is at some distance from the 

 sun are largely the product of mechanical influences. The sugges- 

 tions made by JNIr. Lampland in the preceding paper that of certain 

 prominences the inner arches seem to circle around the prominence 

 while the outer arches were pointed, is in my opinion very signifi- 



