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. CAROLINE. Indeed, I think the remedy must be nearly as bad as the disease; the oxy-muriatic acid has such a dreadfully suffocating smell. MRS. B. It is certainly extremely offensive; but by keeping the mouth shut, and wetting the nostrils with liquid ammonia, in order to neutralize the vapour as it reaches the nose, its prejudicial effects may be in some degree prevented. At any rate, however, this mode of disinfection can hardly be used in places that are inhabited. And as the vapour of nitric acid, which is scarcely less efficacious for this purpose, is not at all prejudicial, it is usually preferred on such occasions. CAROLINE. You have not told us yet what is Sir H. Davy’s new opinion respecting the nature of muriatic acid, to which you alluded a few minutes ago? MRS. B. True; I avoided noticing it then, because you could not have understood it without some previous knowledge of the oxy-muriatic acid, which I have but just introduced to your acquaintance. Sir H. Davy’s idea is that muriatic acid, instead of being a compound, consisting of an unknown basis and oxygen, is formed by the union of oxy-muriatic gas with hydrogen. EMILY. Have you not told us just now that oxy-muriatic gas was itself a compound of muriatic acid and oxygen? MRS. B. Yes; but according to Sir H. Davy’s hypothesis, oxy-muriatic gas is considered as a simple body, which contains no oxygen--as a substance of its own kind, which has a great analogy to oxygen in most of its properties, though in others it differs entirely from it. --According to this view of the subject, the name of _oxy-muriatic acid_ can no longer be proper, and therefore Sir H. Davy has adopted that of _chlorine_, or _chlorine gas_, a name which is simply expressive of its greenish colour; and in compliance with that philosopher’s theory, we have placed chlorine in our table among the simple bodies. CAROLINE. But what was Sir H. Davy’s reason for adopting an opinion so contrary to that which had hitherto prevailed? MRS. B.