_c._ In the experiments made to ascertain these properties all the salt was expended, otherwise I should have endeavoured to ascertain what quantity of gas would have been liberated by heat from a given weight; and likewise what would have been the effects of admixture of it with oil. When some of the mixed salt was mingled with oil of turpentine, part of it was dissolved, and the fluid became white; but no gas was given out. On this coarse experiment, however, I cannot place much dependance. If the combination of nitrous oxide and potash is capable of combining with oil without decomposition, barytes and strontian[159] will probably separate the oil from it, and thus it may possibly be obtained in a state of purity. [159] Unless the sum of affinity of the potash, oil, nitrous oxide, and earths, should be inch as to enable the nitrous oxide to combine with the earth, whilst the oil and alkali remained in combination, & c. In a rough experiment made on the conversion of nitrous gas into nitrous oxide, by concentrated solution of sulphite of potash with excess of alkali, very little of the nitrous oxide was absorbed. Hence it is probable that water lessens the affinity of potash for nascent nitrous oxide. VIII. _Combination of Nitrous Oxide with Soda._ The union of nitrous oxide with soda is effected in the same manner as with potash. The alkali, mingled by solution and evaporation, with either sulphite of soda, or of potash, is exposed to nitrous gas; the nitrous oxide is condensed by it at the moment of generation, and the combination effected. As far as I have been able to observe, nitrous oxide is not absorbed to so great an extent by soda, as potash. I have not yet been able to obtain the combination of nitrous oxide with soda in its pure state. To the attainment of this end, difficulties identical with those noticed in the last section present themselves. It is extremely difficult to procure the soda perfectly free from carbonic acid, and though by using sulphite of potash the sulphate formed is easily separated, yet still evaporation and crystalisation will not disengage the sulphite and carbonate from the new compound. The compound of soda and nitrous oxide, mingled with a little sulphite and carbonate of soda, was rapidly soluble, both in warm and cold water, without effervescence. Its solution, heated to ebullition, gave out no gas. The taste of the solid salt was caustic, and more acrid than that of the mixture of carbonate and sulphite of soda. When cast upon zinc in fusion, it burnt with a white flame. When heated to 400° or 500°, it gave out nitrous oxide with rapidity. Nitrous oxide was expelled from it by the sulphuric, muriatic, and carbonic acids, _I believe_, by sulphurated hydrogene.[160] [160] For when a little of the mixed salt was introduced into a solution of sulphurated hydrogene, globules of gas were given out during the solution. IX. _Combination of Nitrous Oxide with Ammoniac._