The lower part of the tube is adapted to an orifice in the shelf of the mercurial apparatus, so as to make an angle of about 40° with the surface of the mercury. The flame of a small spirit lamp is then applied to that part of the tube containing the fluid; and after the expulsion of the gas from it, the heat is raised so as to drive out the fluid through the orifice of the tube. Thus the liberated gas is preserved in a state proper for accurate examination. Impregnated ether, during its combination with water, gives out the greater part of its nitrous oxide. During the liberation of nitrous oxide from ether, by its combination with water, a very curious phænomenon takes place. If the water employed is colored, so that it may be seen in a stratum distinct from the impregnated ether, at the point of contact a number of small spherules of fluid will be perceived, apparently repulsive both to water and ether; these spherules become gradually covered with minute globules of gas, and as this gas is liberated from their surfaces, they gradually disappear. _b._ Alcohol dissolves considerable quantities of nitrous oxide. 2 cubic inches of alcohol, at 52°, combined with 2,4 cubic inches of nitrous oxide. The alcohol thus impregnated had a taste rather sweeter than before, but in other physical properties was not perceptibly altered. Nitrous oxide is incapable of remaining in combination with this fluid at the temperature of ebullition; it is liberated from it unaltered by heat. Impregnated alcohol, during its combination with water, gives out the greater part of its combined nitrous oxide: on mingling the two fluids together, at the point of contact the alcohol becomes covered with an infinite number of small globules of gas, which continue to be generated during the whole of the combination, and in passing through the fluid render it almost opaque. _c._ The essential oils absorb nitrous oxide to a greater extent than either alcohol or ether. ,5 cubic inches of oil of carui combined with 1,2 cubic inches of nitrous oxide at 51°. The color of the oil thus impregnated was rather paler than before. Nitrous oxide is expelled unaltered from impregnated oil of carui, by heat. 1 of oil of turpentine absorbed nearly 2 of nitrous oxide, at 57°. Its properties were not sensibly altered from this combination, and the gas was expelled from it undecompounded, by heat. _d._ As well as the essential oils, the fixed oils dissolve nitrous oxide at low temperatures, whilst at high temperatures they do not remain in combination. 1 of olive oil absorbed, at 61°, 1,2 of nitrous oxide, but without undergoing any apparent physical change. III. _Action of Fluid Acids on Nitrous Oxide._ _a._ Nitrous oxide exposed to concentrated sulphuric acid, undergoes no change, and suffers no diminution, that may not be accounted for from the abstraction of a portion of its water by the acid.