1891. | NEW YORK ACADEMY OF SCIENCES. 43 
it was never to be seen; since 1877 it is never to be overlooked. 
Wherefore ?” 
This was the statement of the case in the Selenographical Journal 
for June 19th, 1879. Thereafter the Jowrnal published numerous 
drawings 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. Neison 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 
itis now. Although there are very many drawings of that part of 
the moon, there is not a single one that shows it. mn 
Although the evidence br ought 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 objection being that ‘“‘when your attention is directed to a 
thing, the thing is easily seen.’” 
I was encouraged to take up this question by the Director of the 
Lick Observatory, Prof. E. 8. 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 phctograph 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 next 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 16th, 1870, there appears to be a dark marking in the place 
where Hyginus N. shows 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 R. A. Proctor, on page 240, that he examined sey- 
eral photographs of the moon by Rutherfurd, and thought he saw 
on the positive of September 16, 1870, Hyginus N. 
1 The Observatory, No. 60, 1882, p. 102. 
* Remark by Prest. Stone, R. A. S. Observatory, No. 60, p. 105. 
