Focus; and in the path of the light is placed a glass beaker containing a dilute solution of sodium thiosulphate (hyposulphite of soda).
The hyposulphite experiment here again affords an excellent illustration.
By acting upon a solution of sodium hyposulphite with potassium bisulphate, Gernez (Compt.
Rend., 1891, 112, p. 866) is obtained by mixing a solution of sodium hyposulphite with double its volume of hydrochloric acid, filtering and extracting with chloroform; the extract yielding the variety on evaporation.
In systematic chemistry, sodium hyposulphite is a salt of hyposulphurous acid, to which Schutzenberger gave the formula H 2 S0 2, but which Bernthsen showed to be H 2 S 2 0 4.