278 ON THE CHANGE EFFECTED IN THE NITRATES OF POTASH AND SODA 



of the contained oxygen, afterwards restrains the evolution of a further portion, 

 until the heat is raised to a point capable of effecting such a decomposition as 

 to evolve the nitrogen and oxygen in a state of mixture. 



Having, in obtaining large quantities of oxygen, for my experiments in 

 fusing platinum, collected a great quantity of the indurated compound of hy- 

 po-nitrite and nitrate by the process above mentioned, I vs^as induced to substi- 

 tute these salts for nitrate of potash, or nitric acid, in the evolution of the liquid, 

 commonly known as nitrous, or nitric ether. When, for this object, nitric acid, 

 or, what amounts to the same thing, when a nitrate and sulphuric acid are em- 

 ployed, so as to bring free nitric acid into contact with alcohol, there must be 

 an excess of two atoms of oxygen for each atom of hypo-nitrous acid which en- 

 ters into combination with the elements of the alcohol. 



This causes a wasteful decomposition of a proportionable quantity of the 

 last mentioned material, and the generation of some impurities. This view of 

 the subject led me to infer that, to obtain pure hypo-nitrous ether with the 

 greatest economy of materials, a hypo-nitrite should be employed, with a re- 

 agent capable of liberating hypo-nitrous acid, in lieu of a nitrate or nitric acid 

 being distilled with alcohol. The result of an experiment made under this im- 

 pression justified this inference. By subjecting alcohol, mingled with a con- 

 centrated solution of a hypo-nitrite, to diluted sulphuric acid, I obtained an 

 ether, which differs from the ether ordinarily known as nitric, or nitrous ether, 

 in having a more bland and saccharine taste, milder odour, and greater vola- 

 tility. It boils below 65° F., and, by its spontaneous evaporation from the bulb 

 of a thermometer, produces a cold of 15° below zero F. Touched with the 

 finger, or tongue, it hisses as does water with a red hot iron. 



If, after having boiled for some time, it be allowed to stand for awhile at a 

 temperature below its boiling point, the boiling will recommence at a lower 

 temperature than that which was indicated by the thermometer when the boil- 

 ing ceased. 



This seems to arise from the partial resolution of the ether into an ethereal 

 gas ; which appears to be formed by the materials by which the liquid ether is 

 generated, even when refrigerated below the freezing point. I have collected 

 this aeriform ether in large quantities in bells over mercury. When subjected 

 to great pressure, it condenses, more or less, into a yellow liquid, which pro- 

 duces, when allowed to escape into the mouth or nostrils, the same impression 



