SUMMARY OF RESULTS AND SUGGESTIONS. 153 



9. These include several showing the coronal rays to a greater 

 distance from the sun than they have ever been photographed 

 before. 



10. And cast fresh light upon their structure. 



11. Beside restoring the credit of many old drawings of 

 eclipses, which had been supposed untrustworthy because of 

 their want of resemblance to the photographs. 



12. The wide range of exposures employed furnishes a most 

 valuable guide as to the exposures to be employed in future 

 eclipses. 



13. The corona has been definitely photographed during the 

 partial phase. 



14. In several different and independent ways a measure has 

 been obtained of the total illumination given by the corona. 



The chief suggestions as to future work arising from these 

 results appear to group themselves under the following principal 

 heads : 



Drawings of the corona. 

 Spectroscopic observations. 



The proper exposure to be given to photographs of the 

 corona. 



Photographs during the partial phase. 

 Determinations of the brightness of the corona. 



HINTS FOR MAKING DRAWINGS OF THE CORONA.* 



1 . The party should consist of at least five persons ; four to 

 sketch details of single quadrants, and one (the leader) to sketch 

 rapidly the general features of the corona. The leader will then 

 be able to correct and supplement the work of the quadrant 

 sketchers, when producing the combined sketch. This must 

 be done on the same day, immediately after the eclipse, and in 

 consultation with the whole party ; and all the drawings should 

 be photographed as soon as completed. The drawings them- 

 selves, even if faulty, should not be touched after completion. 



2. The party should practise together beforehand, each one 

 sketching his own proper quadrant from a corona-drawing 

 suspended at the angular height of the sun. The time of 

 exposure of the drawing should be slightly less than the known 

 duration of the eclipse. By rotating the drawing it may be 

 made to serve for four sketches. The drawing must be well 

 illuminated and clear ; but must not be large. The sun and 

 moon are small objects to the eye, and a large drawing would 

 not give useful practice. 



3. Experience shows that Mr. Green's suggestion as to 



* By H. Keatley Moore. 



