Finally, to prove that the substance remaining on the filter was none other than hydrated sesqui-oxide of iron (rust), we have treated some of it with hydrochloric acid; it dissolved completely, and the solution presented a greenish-yellow color; the other part, treated by the prussiate
of potash, produced an abundant precipitate of Prussian blue.
Additionally, a new entry in Chemical Cuisine for Yellow prussiate
of soda stated the anti-caking agent, used by salt manufacturers, is safe, despite the fact that the ingredient contains cyanide.
Then, chemicals like silico aluminate, potassium iodide, tri-calcium phosphate, magnesium carbonate, sodium bicarbonate and yellow prussiate
of soda are added.