A feature of Lake Albert Edward Nyanza is the thick haze which overhangs the water during the dry season, blotting out from view the mountains.
Scale-mosses are mounted in the same way, or may be floated out in water like sea-weeds, and dried in white blotting paper under strong pressure before gumming on paper, but are best mounted as microscopic slides, care being taken to show the stipules.
When freed from excess of water it is laid on a sheet of thick white blotting-paper, and a piece of smooth washed calico is placed upon it (unwashed calico, on account of its "facing," adheres to the sea-weed).
This is interesting as an example of what was known as memoriae damnatio or the blotting out of a name on account of some dishonourable action.
Saltpetre may be made to act as a nitrite by dissolving it in water in the strength of about fifty grains to the ounce, soaking blotting-paper in the solution and letting the paper dry.