PRESSURE OF EXPLODED BLASTING GELATIN. 443 



The explosion produces 



177CO 2 + 143H 2 + 81N 2 . 



7. The heat liberated by its explosion is equal to 19381 

 Cal. (gaseous water) ]or 2241 Gal. (liquid water) ; or, for 1 kgm., 

 1535 Cal. (gaseous water), or 1761 Cal. (liquid water). 



8. Eeduced volume of the gases = 8950 litres (gaseous water) 

 or 5759 litres (liquid water) ; or, for 1 kgm., 709 litres (gaseous 

 water), or 456 litres (liquid water). 



9. The permanent pressure (liquid water) = - : , with 



n 0*41 

 the usual reservations. 



10. The theoretical pressure = 1 , value nearly 



Tit 



identical with that of nitroglycerin (p. 425). 



It might have been supposed that the pressure and the heat 

 developed would have been greater owing to the complete 

 utilisation of the oxygen, but there is a compensation on account 

 of the greater loss of energy which takes place at the outset in 

 the union of the elements, and afterwards in the combination of 

 nitric acid with the cellulose, which liberates 11*4 Cal. per 

 equivalent of fixed acid instead of 4'9 Cal. liberated in the case 

 of nitroglycerin (see p. 282). 



Hence it will be seen that blasting gelatin considerably sur- 

 passes ordinary dynamite in the ratio of 19 : 14 according to 

 theory. The ratio of the actual effects of the two substances has 

 been estimated by Hess, by the aid of practical tests based 

 on the rupture of strong pieces of wood. It has been found to 

 approach the numbers 78 : 56, which notably are in accord. 



