HYDROGEN INTO ATOMS 



199 



TABLE XXI 



Observed and Calculated Values of Wn 



necessary to substract Wc- In the last two cohimns of Table XX are the 

 calculated values of Wc for pure nitrogen and hydrogen at pressures of 

 600 mm. These are obtained by multiplying S by the values of 92 — (pi 

 given in Tables III and IV. For the mixture of hydrogen and nitrogen Wc 

 was found by interpolating linearly between the values calculated for the 

 pure gases. By subtracting these results from the watts per cm. of Table 

 XX the values of W^ given in Table XXI as "cal." were obtained. The 

 smallness of the differences at lower temperatures shows that the heat 

 carried by convection in mixtures of gases is approximately an additive 

 function of the partial pressures (the total pressure remaining constant). 

 To calculate the values of W^ for mixtures of gases according to our 

 theory we need to start from Equation 27. From this we can eliminate 

 pi and p2 as bf ore, by means of Equation 30. The significance of P and po, 

 however, is now somewhat different, as we must proceed from this point in 

 a slightly different way. In Equation 30, P is the total pressure, and pi 

 the partial pressure of atomic hydrogen. We then have 



= /)- — 1 



po - 'Up, 



(79) 



where po is the partial pressure of molecular hydrogen before dissociation 



