452 proceedings of the american academy. 



Summary of Results. 



1. The equilibrium pressure of carbon monoxide in the reaction 



CaO + 3 C =t CaC 2 x CO 



was measured at 1475° and 1445°. The results were in good thermo- 

 dynamic agreement. 



2. A little below 1445° C. the pressure becomes too small to meas- 

 ure; a little above 1475° decomposition of calcium carbide into 1 its 

 elements prevents measurement of equilibrium. 



3. With the aid of the heat of the reaction the vapor pressure curve 

 at higher temperatures was computed which cannot be realized experi- 

 mentally on account of the decomposition of calcium carbide. 



4. The free energy increases of the reaction 



CaO + 3 C = CaC 2 + CO 



at 1475° is +23700 calories. 



Electrochemical Laboratory, Rogers Laboratory of Physics, 

 Massachusetts Institute of Technology, 

 Boston, Mass. 



