What do they look like?

Yellow para-realgar with traces of red realgar
© Larry Carr

White arsenic salts visible on a taxidermised bird
© Birmingham Museums Trust

Bottle of iron, arsenic and digitalin tablets, London, 1916-1940
© The Board of Trustees of the Science Museum

Powder spray for Paris green, France, 1925-1935
© The Board of Trustees of the Science Museum