294 



Mr. J. N. Lockyer. 



[Nov. 23, 



Fact. — There is a very wide difference between the spectra. 



2. Motion in the iron vapour, 

 e.g., in a spot or a prominence, 

 should be indicated by the con- 

 tortion of all the iron lines 

 equally. 



Motion should be unequally 

 indicated, because the lines are 

 due to divers constituents which 

 exist in different strata according* 

 as they can resist the higher tem- 

 peratures of the interior regions. 



Fact. — The indications show both rest and motion. 



3. The spectrum of iron in a 

 prominence should be the same as 

 the spectrum of iron in a sun- 

 spot. 



The spectrum of iron in a pro- 

 minence should be vastly different 

 from the spectrum of iron in a 

 sun-spot, because a spot is cooler 

 than a prominence. 



Fact. — The spectra are as dissimilar as those of any two elements. 



4. The spectra of spots and pro- The spectra should vary, because 

 minences should not vary with the the sun is hotter at maximum, 

 sun-spot period. 



Fact. — They do vary. 



5. The spectrum of the base of 

 the solar atmosphere should most 

 resemble the ordinary Fraunhofer 

 spectrum. 



The spectrum of the base should 

 least resemble the Fraunhofer spec- 

 trum, because at the base we only 

 get those molecules which can 

 resist the highest temperatures. 



Fact. — As a rule the lines seen at the base are either faint Fraunhofer 

 lines, or are entirely absent from the ordinary spectrum of the 



6. Qua the same element the 

 lines widest in spots should 

 always be the same. 



Qua the same element the lines 

 widest in spots should vary enor- 

 mously, because the absorbing 

 material is likely to originate in 

 and to be carried to different 

 depths. 



Fact. — There is immense variation. 



7. The spectra of prominences 

 should consist of lines familiar to 

 us in our laboratories, because 

 solar and terrestrial elements are 

 the same. 



The spectra of prominences 

 should be in most cases unfamiliar, 

 because prominences represent out- 

 pourings from a body hot enough 

 to prevent the coming together of 

 the atoms of which our chemical 

 elements are composed. 



