1891. J NEW YORK ACADEMY OF SCIENCES. 43 



it was never to be seen; since IStl it is never to be overlooked. 

 Wherefore ?" 



This was the statement of the case in the Selenographical Journal 

 for June 19th, 1879. Thereafter the Journal published numerous 

 drawing's showing Hyginus N. In various astronomical papers and 

 journals is to be found frequent mention of this interesting- ques- 

 tion. 



At the meeting of the Royal Astronomical Society of London, 

 in April, 1882, Mr. Nelson gave a succinct account of the observa- 

 tions made by himself and others on this portion of the moon. He 

 believes the marking new, and says: "What its real nature is — 

 whether it is a volcanic elevation, whether it is a break down, 

 whether it is a black surface, or what it is — I do not know ; but it 

 is a certain black object which was not there when I observed it 

 before 1877, when Prof. Schmidt and Dr. Klein observed it, who 

 could not have overlooked it if it had been anything as distinct as 

 it is now. Although there are very many drawings of that part of 

 the moon, there is not a single one that shows it.'" 



Although the evidence brought forward is considered very strong 

 and appears almost like proof of a change in lunar marking, yet 

 astronomers have not regarded the evidence as sufficient; the pith 

 of their oljjection being that " when your attention is directed to a 

 thinii:, the thing is easilv seen."* 



I was encouraged to take up this question by the Director of the 

 Lick Observatory, Prof. E. S. Holden, 



Knowing that the Columbia College Observatory had received 

 from Mr. Rutherfurd all his lunar photographs, most of them taken 

 before 1876, Prof. Holden suggested that we were the only persons 

 in the world who possessed the requisite material for settling the 

 question. 



Our first examination was as to whether the photographs taken 

 during the past few years show the marking Hyginus N. 



This was answered in the affirmative. The photograph taken 

 August 15th, 1888, by Prof. Holden, and the photograph by W. 

 H. Pickering in 1889, showing Hipparchus and the surrounding 

 region, seem to me to show plainly the marking. Being satisfied 

 that the marking can be photographed, I ne.xt examined a number 

 of positives made by Rutherfurd; these were sealed and could not 

 be examined as closely as desired. On the positive taken Septem- 

 ber lC)th, 1870, there appears to be a dark marking in the place 

 where Hyginus N. show^s itself in the later photographs. The 

 phase is not the best suited for such examination. This marking 

 was also seen by Mr. H. Jacoby. I find, too, in " Poetry of As- 

 tronomy," by Ru A. Proctor, on page 240. that he examined sev- 

 eral photographs of the moon by Rutherfurd. and thought he saw 

 on the positive of September 16, 1870, Hyginus N. 



1 The Observatory, No. (30, 1882, p. 102'. 



" Remark by Prest. Stone, R. A. S. Observatory, No. 60, p. 105, 



