PRESSURE OF EXPLODED NITROGEN SULPHIDE. 403 



to the gaseous state, lastly from the gaseous state developed 

 towards 448, in which sulphur has a density treble its theo- 

 retical density, to the state in which it resumes its normal 

 density. This calculation cannot be performed solely upon the 

 basis of experimental data, which are partly wanting. We 

 have shown how they can be compensated for, up to a certain 

 point (p. 27). The reader will there find the data for the 

 calculation, of which the results will simply be given here. 



4. The theoretical temperature developed by the explosion 

 of nitrogen sulphide may be estimated at 4375. 



5. Let us now estimate the pressures. 



Take first the permanent pressure, that is, the pressure after 

 cooling, the explosion having taken place in a constant capacity. 

 For a density of charge equal to unity, the pressure at would 

 be 242'6 atm., if the volume occupied by the sulphur were 

 nil. But one litre in reality contains 340 c.c. of solid sulphur ; 

 the permanent pressure will therefore become 367'6 atm. ; or 

 390 kgm. per square centimetre, admitting Mariotte's law. 



If the nitrogen sulphide had exploded in an entirely filled 

 capacity, that is to say in its own volume, one kgm. would 

 occupy only 450 c.c. After explosion, the volume of the solid 

 sulphur being deducted, there would remain 110 c.c. for the 

 nitrogen; which would bring the theoretical pressure to 

 2205'6 atm., or 2340 kgm. per square centimetre. 



In general, one kgm. of this substance enclosed in a capacity 



of n litres, that is to say, supposing the density of charge to be -, 



n 

 the permanent pressure per square centimetre will be 



250*4 kgm. 

 n - 0-340 * 



a theoretical value which will be the nearer the real one the 

 greater n is. 



6. The calculation of the pressures developed at the moment 

 of explosion is more hypothetical ; we shall, however, refer to it 

 as a term of comparison (see p> 28). This calculation should 

 be performed on the supposition of the sulphur being gaseous at 

 the time of the explosion. The pressure developed will then 

 be, for a density of charge equal to unity 



485-2 atm. (l -f^). 

 Supposing t = 4375, as has been said above, 



17>0 ' 



and the above product becomes 8246 atm. ; or 8555 kgm. per 

 square centimetre. 



2 D 2 



