280 COMPOUNDS DERIVED FROM NITRIC ACID. 



letting pure alcohol fall, in exceedingly minute drops, into nitric 

 acid, which is pure and free from nitrous compounds. With 

 each addition the acid is stirred vigorously, in order to avoid 

 any local elevation of temperature. At the same time the 

 vessel containing the acid is moved about in the water of the 

 calorimeter, so as to cause the gradual absorption of the heat 

 disengaged. 



These are essential conditions. When they are very scrupu- 

 lously observed, we succeed in avoiding all secondary reactions, 

 as well as any disengagement of nitrous vapours, and in con- 

 verting the alcohol entirely, or almost entirely, into nitric ether, 

 as we can prove by precipitating the mixture, immediately it is 

 formed, by means of water, and collecting and weighing the 

 ether produced. 



The addition of urea to the pure nitric acid does not render 

 the experiment more successful ; but it is different when a less 

 concentrated acid is used, as in the usual method of preparation 

 of nitric ether. 



The only essential condition is that the drops of alcohol 

 should be excessively small, and very rapidly mixed with the 

 mass, so as to avoid any local elevation of temperature, which 

 would promote secondary reactions. 



The experiment does not always succeed, and it is better 

 only to take into consideration the calorimetric measurements 

 got by means of a successful reaction. On some occasions 7'6, 

 on others 15 grins, of nitric acid and "84 grm. of alcohol were 

 experimented upon by the author. After the reaction, the 

 products should immediately be poured into water, otherwise 

 a secondary reaction begins to manifest itself. The latter 

 reaction is also quickly developed when pure nitric ether, pre- 

 pared beforehand, is dissolved in pure nitric acid, an operation 

 which the author was compelled to perform in the calorimeter, 

 in order to complete the data of the calculations relating to 

 the formation of nitric ether. 



2. After all calculations, it is found that the formation of 

 nitric ether 



C 2 H 6 (liquid) + HN0 3 (liquid) = C 2 H 4 (HN0 3 ) (liquid) 

 + H 2 (liquid), 



gives off -f 6'2 Cal. ; the bodies being supposed pure, separated 

 from each other, and taken at the ordinary temperature. 



The heat of solution of nitric ether in water was also 

 measured : 



C 2 H 4 (H]Sr0 3 ) (1 part) + 180 parts of water gives off + '99 ; 

 whence we get 



C 2 H 6 (in solution) + HN0 3 (in solution) = C 2 H 4 (HN0 3 ) (in 

 solution) + H 2 + water absorbs - 3 '2 Cal. 



