In the Reported Investigation, Heats of Solution of Small Amounts of Pyridine Have Been Measured in Mixtures of Chloroform and Carbon Tetrachloride at 25 C. This Data Has Been Interpreted in Terms of a Complex between Chloroform and Pyridine with Simultaneous Solution for K//f and DELTA H//f Degree , using Both the Ideal Dilute Solution Approximation and a Second Approximation Which Attempts to Account for the Effects of Nonideality. the ″best″ Values Determined with the Ideal Dilute Solution Approximation Are K//f Equals 0. 28 1/mole, DELTA H//f Degree Equals Minus 3. 3 Kcal/mole; and K//f Equals 0. 28 1/mole, DELTA H//f Degree Equals Minus 2. 8 Kcal/mole Determined with the Second Approximation.