Because, instead of becoming, like other acids, more dense, and more acid by an addition of oxygen, it is rendered on the contrary more volatile, more pungent, but less acid, and less absorbable by water. These circumstances, therefore, seem to indicate the propriety of making an exception to the nomenclature. The highest degree of oxygenation of this acid has been distinguished by the additional epithet of _oxygenated_, or, for the sake of brevity, _oxy_, so that it is called the _oxygenated_, or _oxy-muriatic acid_. This likewise exists in a gaseous form, at the temperature of the atmosphere; it is also susceptible of being absorbed by water, and can be congealed, or solidified, by a certain degree of cold. EMILY. And how do you obtain the oxy-muriatic acid? MRS. B. In various ways; but it may be most conveniently obtained by distilling liquid muriatic acid over oxyd of manganese, which supplies the acid with the additional oxygen. One part of the acid being put into a retort, with two parts of the oxyd of manganese, and the heat of a lamp applied, the gas is soon disengaged, and may be received over water, as it is but sparingly absorbed by it. --I have collected some in this jar-- CAROLINE. It is not invisible, like the generality of gases; for it is of a yellowish colour. MRS. B. The muriatic acid extinguishes flame, whilst, on the contrary, the oxy-muriatic makes the flame larger, and gives it a dark red colour. Can you account for this difference in the two acids? EMILY. Yes, I think so; the muriatic acid will not supply the flame with the oxygen necessary for its support; but when this acid is further oxygenated, it will part with its additional quantity of oxygen, and in this way support combustion. MRS. B. That is exactly the case; indeed the oxygen added to the muriatic acid, adheres so slightly to it, that it is separated by mere exposure to the sun’s rays. This acid is decomposed also by combustible bodies, many of which it burns, and actually inflames, without any previous increase of temperature. CAROLINE. That is extraordinary, indeed! I hope you mean to indulge us with some of these experiments? MRS. B. I have prepared several glass jars of oxy-muriatic acid gas for that purpose. In the first we shall introduce some Dutch gold leaf. --Do you observe that it takes fire? EMILY. Yes, indeed it does--how wonderful it is! It became immediately red hot, but was soon smothered in a thick vapour. CAROLINE. What a disagreeable smell! MRS. B. We shall try the same experiment with phosphorus in another jar of this acid. --You had better keep your handkerchief to your nose when I open it--now let us drop into it this little piece of phosphorus-- CAROLINE. It burns really; and almost as brilliantly as in oxygen gas! But, what is most extraordinary, these combustions take place without the metal or phosphorus being previously lighted, or even in the least heated. MRS. B.