8) ) 2.8 EIGURE 2.26 shows a Boyle's law prosinxeter normally wed to determine grain volume in routine core analysis. The operation of the instrument is as follows: The sample is placed in the sample clumber and vented to the atmosphere The sample chamber is sealed The reference chamber is pressurized by means of helium. The shut-off valve is closed Once the system comes to equilibrium the souge pressure in the reference changer P) in recorded The three-way valve is opened between the reference chamber and the sample chuber. . Once the system is re-equilibrated the grase pressure (P) is recorded The instrument was calibrated with steel spheres with the results shown in TABLEZIA Sphere Diameter PE (cm) (psig) (psig) 5.816 100 70 5.523 100 50 4.680 100 30 TABLE 2.10 - Calibration data for Boyles law Porosimeter P24 . GAMES MISS b. Plot an appropriate calibration curve for the porosimeter