DINITROGLYCOLIC ETHER. 421 



is to say, within the limits in which carbonic acid retains the 

 gaseous state. 



12. Pressure ab the theoretical temperature, calculated 

 according to the laws of gases 



669 atm. (l + 



15052 atm. 



n n 



or 15,534 kgm. per square centimetre. 



The permanent pressures are much lower than for nitro- 

 e thy lie ether, but the heat liberated is more than double, which 

 gives an advantage to the theoretical pressure. 



4. DINITRO-GI/TCOLIC ETHER : C 2 H2(N0 3 H) 2 . 



1. Equivalent, 152. 



2. Composition^ 



C ......... ... = 158 



H ............... = 26 



N ... .. .......... = 184 



............. ,. = 632 



1000 



This composition is very nearly the same as that of nitro- 

 methylic ether. 



3. The body is liquid. 



4. The heat of formation from the elements calculated from 

 the formula on p. 285 



C 2 (diamond) + H 4 + N 2 + 6 = C 2 H 2 (HN0 3 ) 2 (liquid) -f 66*9 CaL 



5. The heat of total combustion and the heat of explosive 

 decomposition coincide 



C 2 H 2 (N0 3 H) 2 = 2C0 2 4- 2H 2 + N a + 2591 Gal. 



at constant pressure, the water being liquid; -f- 2607 Cal. at 

 constant volume. 



For 1 kgm. we shall have 1705 Cal. at constant pressure, 

 1715 Cal. at constant volume. 



6. Volume of the permanent gases for 1 equiv., 86*9 litres 



\ ~*~ 273/' ^ e water being gaseous 111-6 litres (l + 7^); or > 



for 1 kgm., 440 litres ( 1 -f- - ) for the permanent gases, 

 \ 2if of 



734 litres (l + oijo) when the water is gaseous. 



7. Theoretical temperature 



241 - 900 = 7982 

 33-6 



