Nitrate of soda, Peruvian guano and superphosphate of lime in the form of bones dissolved by sulphuric acid were now added to the list of manures, and the practice of analysing soils became more general.
It dissolves in strong nitric acid with the formation of the nitrate and sulphate, and also in hot concentrated hydrochloric acid.
In the first group, we have to notice the titration of a cyanide with silver nitrate, when a milkiness shows how far the reaction has gone; the titration of iron with permanganate, when the faint pink colour shows that all the iron is oxidized.
The halogens may be estimated by ignition with quicklime, or by heating with nitric acid and silver nitrate in a sealed tube.
By treating blue ultramarine with silver nitrate solution, "silverultramarine" is obtained as a yellow powder.
