﻿158 Intelligence and Miscellaneous Articles, 



Thus this temperature will be given by the equation 



8240-* =/(0 _ ...... (3) 



3240 + (c— c[)t 



If the gaseous mixture, instead of being originally at zero, con- 

 tained more than at zero, a quantity of heat, v, positive or negative, 

 the equations would become 



3240 + v-c't _ ftA 

 k = 3240+ { c-c<)t- M (4) 



If, instead of being dry, the mixture, before any combustion, con- 

 tained a fraction q of its weight in the state of water, we should have 



k _ 3240(l-q) + v-c't _ ( , 



k 3240 + (c-c>)t - /(0 * " * * (5) 



In these various cases nothing is ever present but aqueous vapour 

 and explosive gas ; if we suppose the former to be always the same, 

 the dissociation will only change from one case to the other by the 

 effect of temperature. The function f(f) is therefore always the 

 same. If, therefore, we place ourselves successively in different cases, 

 varying v and q (that is to say, the initial temperature and humidity) , 

 and observe the temperature of combustion, we shall deduce there- 

 from different values of f(t) ; that is to say, we shall get the law 

 which connects the tension of dissociation with the temperature 

 under the pressure in question. 



The equations (4) are equally true at any moment that the quan- 

 tity of heat v is added or deducted. They agree therefore, suppo- 

 sing v to be negative, with the successive states of the mass when it 

 cools from the maximum of temperature. We are thus led to an- 

 other method of obtaining values of f(t), — namely, observing 

 simultaneously, during the cooling of the mass, the quantities of 

 heat which it abandons and the temperatures through which it 

 passes. 



If each kilogramme of more or less hot and moist explosive gas 

 were mixed with a weighty of a gas not capable of entering into re- 

 action, and of specific heat c", we should have 



, 3240(1 -q) + y-(c'+pc") t _ f() 

 3240 + (c-c')t ~ JA) ' 



I here introduce this new function f ± (t), because we may assume, 

 until the contrary is proved, that the presence of a foreign gas modi- 

 fies the dissociation. 



It is evident that, by varying only v and q, we may determine the 

 functionj^). By subsequently varying the nature and the quan- 

 tity of the intermixed gas, we shall see how these conditions modify 

 the dissociation. 



Assuming the identity oif(t) and f^t), -we easily see that if we 

 compare two mixtures for which the temperature of total combustion 

 (that given by the ordinary formulae) is the same, but one dry and 

 containing a foreign gas such as nitrogen, the other with no 



