Theory of the Formation sf Ether, ^^. jpj 



would be out of place in this memoir, correfpond perfeaiy with the rcfult afforded by the 

 theory. 



The foregoing are the effefts producxd by a combination of alcohol and Sulphuric acid, 

 fpontaneouny produced without foreign heat. Let ui in the next place obferve how this 

 combination is effcftcd when caloric is added. The phenomena are then very different, 

 though fome of the refults are the fame. 



In the firfl: place we muft obferve, that a combination of fulphuric acid and alcohol in 

 ct^ual parts does not boil at lefs than 78 degrees of temperature, while that of alcohol alone 

 b^ils at 64. Now fince ebullition does not take place till the higher temperature, it is clear 

 that the alcohol is retained by the affinity of the fulphuric acid^^ which fixes it more conC- 

 derably. Let us alfo confider that organic bodies, or their immediate produds, expofed to 

 a lively brifk heat, without the poffibility of efcaping fpeedily enough from its aftion, fuffer 

 a partial or total decompofition, according to the degree of temperature. Alcohol under- 

 goes this laa alteration when paffed through an ignited tube of porcelain. By this fudden 

 decompofition it is converted into water, carbonic acid, and carbone. The reafon, there- 

 fore, why alcohol is not decompofed when it is fubmltted alone to heat in the ordinary ap- 

 paratus for diftillation, is, that the temperature at which it rifes in vapours is not capable 

 of effeding the reparation of its principles; but when it is fixed by the fulphuric acid or 

 any other body, the elevated temperature it undergoes without the poffibility of difengage- 

 ment from its combination is fuificient to effect a commencement of decompofition, in 

 which ether and water are formed, and carbone is depofited. Nothing more therefore 

 happens to the alcohol in thefe circumltances than what takes place in the diftillation of 

 every other vegetable matter in which water, oil, acid, and coal are afforded. 



Hence it may be conceived that the nature of the produfts of the decompofition of alcohof 

 muft vary according to the different degrees of heat, and this explains why at a certain 

 period no more ether is formed but the fweet oil of wine and acetous acid. \n fad, when 

 the greateft quantity of the alcohol has been changed into ether, the mixture become's more 

 denfe, and the heat which it acquires previous to ebullition is more confiderable. The af- 

 fmity of the acid for alcohol being increafed, the principles of this acid become feparated -. 

 fo that, on the one hand, itsoxygene fcizeslhe hydrogene and forms much water, which is 

 gradually volatilized; while, on the other, the ether retaining a greater quantity of carbone, 

 •with which at that temperature it can rife, affords the fweet oil of wine. This laa ought,' 

 therefore, to be confidered as an ether containing an extraordinary portion of carbone, which 

 gives it more denfity, lefs volatility, and a lemon-yellow colour. 



During the formation of the fweet oil of wine, the quantity of carbone which is preci- 

 pitated is no longer in the fame proportion as during the- formation of ether. 



What we have here ftated concerning the manner in which ether is formed by the fimul- 

 tancous aftion of the fulphuric acid and heat, appears fo conformable to truth, that nearly 

 tlie fame effeds may be produced by a cauftic fixed alkali. In this cafe alfo a kind of 

 ether and a fweet oil of wnne are volatilized, and coal is precipitated. It is therefore only 

 by fixing the alcohol that the fulphuric acid permits the caloric to operate a fort of decom- 

 porfition. It may ^;lfo be urged as a proof of this affcrtion, that the fulphuric acid, which 

 has ferrcd to make ether as fal- as the period at which the fweet oil of wine begins to appear 

 is capable of faturating the fame quantity of alkali as before its mixture with the alcohol. 

 VoT.:I.— December 1797. 3E yif\x\\ 



