252 Intelligence and Miscellaneous Articles. 



it affords the only example of a nitrate which does not yield nitric 

 acid hy the action of sulphuric acid, and at the same time give up 

 its base to this acid, more fixed and energetic than nitric acid. 



When the proportion of sulphuric apid is most diminished, opera- 

 ting, for example, with ten parts to one of nitrate of ammonia, about 

 three-fourths of the salt are decomposed into nitric acid and am- 

 monia, and one-fourth into nitrous oxide and water. By gradually 

 diminishing the proportion of sulphuric acid, but little nitrous oxide 

 is obtained, so that with one equivalent of nitrate of ammonia and 

 two equivalents of sulphuric acid,the phenomena coincide with those 

 of the decomposition of a salt by a more fixed acid. 



When a mixture of nitrate of ammonia and a large excess of sul- 

 phuric acid is heated only between about 200° and 250° Fahr. in- 

 stead of 322° Fahr., nitric acid distils, but without the production 

 of any nitrous oxide. When nitrite of ammonia is heated with a 

 great proportion of concentrated sulphuric acid, it is converted as 

 by the mere action of heat into azote and water. 



It appears from the preceding statements, that very different re- 

 sults are obtained by varying the proportions of nitrate of ammonia, 

 sulphuric acid, the quantity of water and the temperature employed. 

 — Journal de Pharmacie, t. xxvii. p. 271. 



PREPARATION OF AZOTIC GAS. BY M. PELOUZE. 



M. A. Rose has observed that monohydrated sulphuric acid com- 

 bines directly with nitric oxide, and absorbs very considerable quan- 

 tities of it. Sulphate of ammonia being heated in this compound 

 to about 322° Fahr., pure azote gas, perfectly unmixed nitrous 

 or nitric oxide, was obtained. This experiment was varied by 

 passing nitric oxide gas into concentrated sulphuric acid mixed with 

 sulphate of ammonia, and heated from about 300° Fahr. to 392°. 

 The nitric oxide was decomposed as in the preceding experiment, 

 and pure azotic gas was obtained ; it is mixed with nitric oxide only 

 when the disengagement is too rapid. M. Pelouze is of opinion 

 that this method of preparing azotic gas may be advantageously em- 

 ployed. ________ 



CONCENTRATION OF NITRIC ACID BY MEANS OF SULPHURIC 

 ACID. BY M. PELOUZE. 



It is stated in different chemical treatises, that concentrated sul- 

 phuric acid decomposes nitric acid into water, with which it com- 

 bines, and hyponitrous acid. M. Pelouze doubted the accuracy of this 

 statement, and was convinced that it was erroneous, by observing 

 nitric acid distil from a mixture of nitrate of ammonia with great ex- 

 cess of sulphuric acid at 212°. 



500 parts of concentrated sulphuric acid were mixed with 

 100 of nitric acid of specific gravity 1*448 ; the mixture was slowly 

 distilled, and yielded 88 parts of nitric acid of specific gravity 1520 ; 

 this product, freed from red vapour by a gentle heat, was mixed with 

 six and a half times its weight of concentrated sulphuric acid, un- 



