406 Dr. Andrews on the Heat developed during the Formation of the 



32. Sesquichloride of iron and water, Fcj CI3 + Aq. 



Th. air. 

 T. . 

 T. . 

 Inc. c. 

 Aq. . 

 Sn. 



Vss. . 

 Fe,Cl3 

 Heat of comb. 



Mean heat referred to chlorine in CI3 as unit, 453°. 

 Mean heat referred to iron in Fe^ as unit, 887°. 



33. On the principle just stated, we may infer, as a rude approximation, that 

 the heat disengaged during the solution of the sesquibromide of iron would be 

 (referred to the iron as unit) 837° ; and that disengaged during the solution of 

 the sesquiiodide, 682°. 



34. If we now substitute the numerical values, obtained by the preceding 

 experiments, for the known quantities in the equations given before, we shall 

 obtain 



.r = 3086° -320° ±x 

 y= 2586° — 302° ±x' 

 .r"= 1720° — 246° drx" 



y = 4921° — 887° — 788° dr y 

 y' = 3933° - 837° — 794° zb y' 

 y = 2299° — 682° — 783° ± y' 



From these equations we deduce 



w or Zn + CI = 2766° ± x 

 y or Zn + Br = 2284° ± x' 

 x" or Zn + I =z 1474° ± x" 



y orFe2+Cl3 = 3246°±Y 

 «/' or Fe^ + Br, = 2302° dr y' 

 y" or Fe^ + I3 = 834° =t y" 



(16, 20) 

 (17, 21) 

 (18, 22) 



(23, 32, 28) 

 (25, 33, 29) 

 (26, 33, 30) 



