The more I studied the description and the manuscript the stronger
this impression became. Then it occurred to me to inquire whether
perhaps such could have been the case. So I asked Director Weiss
whether anything was known as to the normal character of Littrow's
power of distinguishing colors. His answer was prompt and
decisive. "Oh yes, Littrow was color-blind to red. He could not
distinguish between the color of Aldebaran and the whitest star."
No further research was necessary. For half a century the
astronomical world had based an impression on the innocent but
mistaken evidence of a color-blind man--respecting the tints of
ink in a manuscript.

It has doubtless happened more than once that when an intimate
friend has suddenly and unexpectedly passed away, the reader has
ardently wished that it were possible to whisper just one word of
appreciation across the dark abyss. And so it is that I have ever
since felt that I would like greatly to tell Father Hell the story
of my work at Vienna in 1883.





XVI

THE EVOLUTION OF THE SCIENTIFIC INVESTIGATOR

[Footnote: Presidential address at the opening of the
International Congress of Arts and Science, St. Louis Exposition,
September 21: 1904.]