NITKOMANNITE. 



283 



and Vieille obtained under these conditions, for 100 volumes of 



gas 



NO 48-2 



CO 35-9 



C0 2 12-7 

 H 1-6 



N 1-3 



CH 4 



0-3 



These conditions are similar to those under which a mining 

 charge, simply ignited by the cap, burns away slowly under a 

 low pressure ; this is called a miss-fire. 



3. Nitromannite, C 6 H 2 (HN0 3 ) 6 = 452 grins. 



1. This substance was prepared by means of nitrosulphuric 

 acid. The reaction is slow and somewhat prolonged. One grm. 

 of mannite and 30 grms. of acid liquid were operated upon. 

 Assuming the reaction to have been complete, the numbers that 

 were observed gave + 23*5 Gal. for the reaction 



C 6 H 14 6 + 6HN0 3 = C 6 H 2 (HN0 3 ) e + 6H 2 0, 



or -f- 3 '92 Gal. per equivalent of fixed nitric acid. 



2. The heat of formation of nitromannite from its elements is 

 calculated from the above figures, together with the heat of 

 formation of mannite, as deduced from its heat of combustion 

 (760 Gal.), which was obtained by M. Eechenberg. We thus 

 find 



C 6 (diamond) -f H 8 -f N 6 -f 18 gives off + 156-5 Gal. for 

 452 grms. 



Sarrau and Vieille deduced from the heat of combustion 

 of nitromannite itself its heat of formation, + 165*1 Gal. for 

 452 grms., a value sufficiently close to the above if we take 

 into account the heats of combustion given below; for the 

 difference between the heats of combustion calculated and those 

 found by experiment does not amount to one-hundredth. 



The heat of combustion of nitromannite is the same as its heat 

 of decomposition, this substance containing, like nitroglycerin, 

 an excess of oxygen 



C 6 H 2 (HN0 3 ) 6 = 6C0 2 + 4H 2 +*N a + 2 . 



This reaction gives off, according to calculation, 564 -f- 276 

 - 1561 = + 683-9 Gal. for 452 grms. 



Sarrau and Vieille found directly 678'5 Gal., or, for 1 grm., 

 1501 cal. 



4. Heat of Formation of Nitric Ethers in general 



1. It is desirable to treat here of ethers formed from true 

 alcohols, which have simple functions (p. 268). 



