EMILY.
Their colours begin to fade immediately! But how does the gas produce this effect?
MRS. B.
The oxygen combines with the colouring matter of these substances, and destroys it; that is to say, destroys the property which these colours had of reflecting only one kind of rays, and renders them capable of reflecting them all, which, you know, will make them appear white. Old prints may be cleaned by this acid, for the paper will be whitened without injury to the impression, as printer’s ink is made of materials (oil and lamp black) which are not acted upon by acids.
This property of the oxy-muriatic acid has lately been employed in manufactures in a variety of bleaching processes; but for these purposes the gas must be dissolved in water, as the acid is thus rendered much milder and less powerful in its effects; for, in a gaseous state, it would destroy the texture, as well as the colour of the substance submitted to its action.
CAROLINE.
Look at the things which we put into the gas; they have now entirely lost their colour!
MRS. B.
The effect of the acid is almost completed; and, if we were to examine the quantity that remains, we should find it to consist chiefly of muriatic acid.
The oxy-muriatic acid has been used to purify the air in fever hospitals and prisons, as it burns and destroys putrid effluvia of every kind. The infection of the small-pox is likewise destroyed by this gas, and matter that has been submitted to its influence will no longer generate that disorder.