b. I introduced into a vessel containing 30 grains of platina, 2050 grains of aqua regia, composed of equal parts, by weight, of concentrated nitric acid of 1,43, and muriatic acid of 1,16. At the common temperature, that is, 49°, no action between the acid and platina appeared to take place. On the application of the heat of a spirit lamp, the solution gradually became yellow red, and gas was given out with rapidity. Some of this gas received in a jar filled with warm water, appeared of a bright yellow color. On agitation, the greater part of it was absorbed by the water, and the remainder extinguished flame. When it was received over mercury, it acted upon it with great rapidity, and formed on the surface a white crust.
As the process of solution advanced, the color of the acid changed to dark red, at the same time that the production of gas was much increased; more than 40 cubic inches were soon collected in the water apparatus.
Different portions of the gas were examined, it exhibited the following properties:
1. Its color was orange red,[148] and its smell exactly resembled that of oxygenated muriatic acid.
2. When agitated in boiled water, it was rapidly absorbed, leaving a residuum of rather more than one twelfth.
3. The taper burnt in it with increased brilliancy, the flame being long, and deep red at the edges.
4. Iron introduced into it ignited, burnt with a dull red light.
5. Green vegetables exposed to it were instantly rendered white.
6. It underwent no diminution, mingled with atmospheric air.
7. When mingled with nitrous gas, it gave dense red vapor, and rapid diminution.