The properties of the carbon pile are mentioned here. The resistance R is approximately given in the form R=nC/Pm; where n is the number of carbon piles C & m are the constants and P is the applied force. The resistance of the carbon pile having 1/N times the above area can be calculated by the formula R= (nCN1-m) /Pm. If we decrease the compressive force from the maximum value Pmax to the lower value P. then the car bon discs expand by the amount χ. There exists the following relation between them; P=Pmax10-χ/nk, where k is a constant. And the method of measuring the resistivity, perpendicular to the surface is mentioned.