Hymn Lyrics Search - Name That Hymn

I found the lyrics to this old hymn on this website. Thank you!
However, I've searched all over the internet for the sheet music for it.
Does anyone know where I could find it?
The author of this old hymn is Petersen; however, it is not on his website.

The name of the old hymn I need the sheet music to is "Watchman, What of the Night?"