genuine. So, during my almost daily visits to the observatory, I
asked permission of the director to study Hell's manuscript, which
was deposited in the library of the institution. Permission was
freely given, and for some days I pored over the manuscript. It is
a very common experience in scientific research that a subject
which seems very unpromising when first examined may be found more
and more interesting as one looks further into it. Such was the
case here. For some time there did not seem any possibility of
deciding the question whether the record was genuine. But every
time I looked at it some new point came to light. I compared the
pages with Littrow's published description and was struck by a
seeming want of precision, especially when he spoke of the ink
with which the record had been made. Erasers were doubtless
unknown in those days--at least our astronomer had none on his
expedition--so when he found he had written the wrong word he
simply wiped the place off with, perhaps, his finger and wrote
what he wanted to say. In such a case Littrow described the matter
as erased and new matter written. When the ink flowed freely from
the quill pen it was a little dark. Then Littrow said a different
kind of ink had been used, probably after he had got back from his
journey. On the other hand, there was a very singular case in
which there had been a subsequent interlineation in ink of quite a
different tint, which Littrow said nothing about. This seemed so
curious that I wrote in my notes as follows:

"That Littrow, in arraying his proofs of Hell's forgery, should
have failed to dwell upon the obvious difference between this ink
and that with which the alterations were made leads me to suspect
a defect in his sense of color."