242 The Eclipse of Last December. [April, 



The American photograph is shown in the second figure 

 of the illustrative plate. It will be seen that the extent of 

 the field is limited, as if by a circular stop, to a space of 

 about 12' wide all round the moon's body. Yet the V-shaped 

 gap is shown very distinctly indeed. It is to be noted, also, 

 that there are obvious traces of two other gaps, one about 

 40 round towards the left, and the other about 70 round 

 towards the right. Yet, again, it is to be noted that the 

 depression of the inner corona beneath the great V-shaped 

 gap is very distinctly indicated ; and in other respects the 

 agreement of the part of the corona shown with the indica- 

 tions in figure 9 is most remarkable. 



But now another circumstance invites our attention. The 

 American photograph shows the position of the apex of the 

 gap to have been exactly midway between two prominences. 

 The prominences are, indeed, not actually seen ; but the 

 notching of the moon's disc (caused by the eating away due 

 to their actinic energy) leaves no question as to their 

 existence there. I find two prominences indicated also in 

 this position, not only in Lord Lindsay's photographs, but 

 in some excellent drawings of the eclipse by Lieutenant 

 Watkin, R.A., Lieutenant Sidney G. Smith, R.N., and Mr. 

 Abbatt, F.R.A.S. Now here we have the means of ascer- 

 taining the real existence of this gap as a true solar pheno- 

 menon beyond all possibility of question, — if only another 

 photograph taken at a distant station shall show the gap 

 similarly placed. 



This brings me to what I take to be the crowning achieve- 

 ment of the eclipse expeditions — an achievement well worth 

 all the labour and cost which those expeditions may have 

 involved to the American, British, and Continental Govern- 

 ments and students of science. I refer to the admirable 

 photograph of the corona by Mr. Brothers, F.R.A.S., taken 

 at Syracuse, during only the last few seconds of totality — for 

 clouds rendered the first exposures relatively ineffective. Those 

 eight seconds, however, during which this photograph, the 

 fifth of the series, was exposed, sufficed to give a picture 

 whose scientific value is only surpassed by the interest 

 which attaches to the view as the first really successful 

 photographic delineation of the solar corona. 



This photograph, of which the first view in the illustrative 

 plate is a copy,* is well worth careful study. 



* Mr. Brothers writes to me that there are strange details in the negative 

 which he cannot reproduce, either in photographic copies or by draughtsman- 

 ship. Their extreme delicacy defeats all attempts to reproduce them. Even 

 the extensions seen in the plate have had te> be copied dire&ly from the 

 negative, for they are too delicate to show in ordinary photographic copies. 



