A great reference. Here's the quotation:
"The back sight I use is a straight bar of hard black rubber about thirty-five hundredths of an inch wide, perfectly level on top. Iron or bone soaked with ink will do as well; but iron should be kept corroded with tincture of iodine and then blackened withink. With such a sight and ivory on the ball in front you can swing your rifle around the horizon in the sun and see no change of light-center and not a glimmer from the bar. And you can shoot ten degrees closer to the sun’s eye with them than with any other set of open sights. The very best of all is a piece of hard soleleather, made still harder by boiling and hammering and drying in an oven. Soaked with ink, not a ray of light will this cast. It can be screwed in through a hole." (pp.357-58)
Theodore S. Van Dyke,
The Still Hunter (New York: Fords, Howard & Hulbert, 1882)
